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提交 1867fa64 编写于 作者: G Greg Kroah-Hartman
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Staging: zcache: delete it 

Dan Magenheimer says that it is now safe to delete zcache, so quick,
before he changes his mind, drop the thing on the floor and run
screaming away.
Signed-off-by: NDan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
上级 d178a07c
隐藏空白更改
内联 并排
Showing with 0 addition and 3073 deletion
drivers/staging/Kconfig
浏览文件 @ 1867fa64
......@@ -74,8 +74,6 @@ source "drivers/staging/iio/Kconfig"
source "drivers/staging/zram/Kconfig"
source "drivers/staging/zcache/Kconfig"
source "drivers/staging/zsmalloc/Kconfig"
source "drivers/staging/wlags49_h2/Kconfig"
......
drivers/staging/Makefile
浏览文件 @ 1867fa64
......@@ -31,7 +31,6 @@ obj-$(CONFIG_VME_BUS) += vme/
obj-$(CONFIG_DX_SEP) += sep/
obj-$(CONFIG_IIO) += iio/
obj-$(CONFIG_ZRAM) += zram/
obj-$(CONFIG_ZCACHE) += zcache/
obj-$(CONFIG_ZSMALLOC) += zsmalloc/
obj-$(CONFIG_WLAGS49_H2) += wlags49_h2/
obj-$(CONFIG_WLAGS49_H25) += wlags49_h25/
......
drivers/staging/zcache/Kconfig 已删除 100644 → 0
浏览文件 @ d178a07c
config ZCACHE
bool "Dynamic compression of swap pages and clean pagecache pages"
depends on (CLEANCACHE || FRONTSWAP) && CRYPTO=y && ZSMALLOC=y
select CRYPTO_LZO
default n
help
Zcache doubles RAM efficiency while providing a significant
performance boosts on many workloads. Zcache uses
compression and an in-kernel implementation of transcendent
memory to store clean page cache pages and swap in RAM,
providing a noticeable reduction in disk I/O.
drivers/staging/zcache/Makefile 已删除 100644 → 0
浏览文件 @ d178a07c
zcache-y := zcache-main.o tmem.o
obj-$(CONFIG_ZCACHE) += zcache.o
drivers/staging/zcache/tmem.c 已删除 100644 → 0
浏览文件 @ d178a07c
/*
* In-kernel transcendent memory (generic implementation)
*
* Copyright (c) 2009-2011, Dan Magenheimer, Oracle Corp.
*
* The primary purpose of Transcendent Memory ("tmem") is to map object-oriented
* "handles" (triples containing a pool id, and object id, and an index), to
* pages in a page-accessible memory (PAM). Tmem references the PAM pages via
* an abstract "pampd" (PAM page-descriptor), which can be operated on by a
* set of functions (pamops). Each pampd contains some representation of
* PAGE_SIZE bytes worth of data. Tmem must support potentially millions of
* pages and must be able to insert, find, and delete these pages at a
* potential frequency of thousands per second concurrently across many CPUs,
* (and, if used with KVM, across many vcpus across many guests).
* Tmem is tracked with a hierarchy of data structures, organized by
* the elements in a handle-tuple: pool_id, object_id, and page index.
* One or more "clients" (e.g. guests) each provide one or more tmem_pools.
* Each pool, contains a hash table of rb_trees of tmem_objs. Each
* tmem_obj contains a radix-tree-like tree of pointers, with intermediate
* nodes called tmem_objnodes. Each leaf pointer in this tree points to
* a pampd, which is accessible only through a small set of callbacks
* registered by the PAM implementation (see tmem_register_pamops). Tmem
* does all memory allocation via a set of callbacks registered by the tmem
* host implementation (e.g. see tmem_register_hostops).
*/
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include "tmem.h"
/* data structure sentinels used for debugging... see tmem.h */
#define POOL_SENTINEL 0x87658765
#define OBJ_SENTINEL 0x12345678
#define OBJNODE_SENTINEL 0xfedcba09
/*
* A tmem host implementation must use this function to register callbacks
* for memory allocation.
*/
static struct tmem_hostops tmem_hostops;
static void tmem_objnode_tree_init(void);
void tmem_register_hostops(struct tmem_hostops *m)
{
tmem_objnode_tree_init();
tmem_hostops = *m;
}
/*
* A tmem host implementation must use this function to register
* callbacks for a page-accessible memory (PAM) implementation
*/
static struct tmem_pamops tmem_pamops;
void tmem_register_pamops(struct tmem_pamops *m)
{
tmem_pamops = *m;
}
/*
* Oid's are potentially very sparse and tmem_objs may have an indeterminately
* short life, being added and deleted at a relatively high frequency.
* So an rb_tree is an ideal data structure to manage tmem_objs. But because
* of the potentially huge number of tmem_objs, each pool manages a hashtable
* of rb_trees to reduce search, insert, delete, and rebalancing time.
* Each hashbucket also has a lock to manage concurrent access.
*
* The following routines manage tmem_objs. When any tmem_obj is accessed,
* the hashbucket lock must be held.
*/
static struct tmem_obj
*__tmem_obj_find(struct tmem_hashbucket*hb, struct tmem_oid *oidp,
struct rb_node **parent, struct rb_node ***link)
{
struct rb_node *_parent = NULL, **rbnode;
struct tmem_obj *obj = NULL;
rbnode = &hb->obj_rb_root.rb_node;
while (*rbnode) {
BUG_ON(RB_EMPTY_NODE(*rbnode));
_parent = *rbnode;
obj = rb_entry(*rbnode, struct tmem_obj,
rb_tree_node);
switch (tmem_oid_compare(oidp, &obj->oid)) {
case 0: /* equal */
goto out;
case -1:
rbnode = &(*rbnode)->rb_left;
break;
case 1:
rbnode = &(*rbnode)->rb_right;
break;
}
}
if (parent)
*parent = _parent;
if (link)
*link = rbnode;
obj = NULL;
out:
return obj;
}
/* searches for object==oid in pool, returns locked object if found */
static struct tmem_obj *tmem_obj_find(struct tmem_hashbucket *hb,
struct tmem_oid *oidp)
{
return __tmem_obj_find(hb, oidp, NULL, NULL);
}
static void tmem_pampd_destroy_all_in_obj(struct tmem_obj *);
/* free an object that has no more pampds in it */
static void tmem_obj_free(struct tmem_obj *obj, struct tmem_hashbucket *hb)
{
struct tmem_pool *pool;
BUG_ON(obj == NULL);
ASSERT_SENTINEL(obj, OBJ);
BUG_ON(obj->pampd_count > 0);
pool = obj->pool;
BUG_ON(pool == NULL);
if (obj->objnode_tree_root != NULL) /* may be "stump" with no leaves */
tmem_pampd_destroy_all_in_obj(obj);
BUG_ON(obj->objnode_tree_root != NULL);
BUG_ON((long)obj->objnode_count != 0);
atomic_dec(&pool->obj_count);
BUG_ON(atomic_read(&pool->obj_count) < 0);
INVERT_SENTINEL(obj, OBJ);
obj->pool = NULL;
tmem_oid_set_invalid(&obj->oid);
rb_erase(&obj->rb_tree_node, &hb->obj_rb_root);
}
/*
* initialize, and insert an tmem_object_root (called only if find failed)
*/
static void tmem_obj_init(struct tmem_obj *obj, struct tmem_hashbucket *hb,
struct tmem_pool *pool,
struct tmem_oid *oidp)
{
struct rb_root *root = &hb->obj_rb_root;
struct rb_node **new = NULL, *parent = NULL;
BUG_ON(pool == NULL);
atomic_inc(&pool->obj_count);
obj->objnode_tree_height = 0;
obj->objnode_tree_root = NULL;
obj->pool = pool;
obj->oid = *oidp;
obj->objnode_count = 0;
obj->pampd_count = 0;
(*tmem_pamops.new_obj)(obj);
SET_SENTINEL(obj, OBJ);
if (__tmem_obj_find(hb, oidp, &parent, &new))
BUG();
rb_link_node(&obj->rb_tree_node, parent, new);
rb_insert_color(&obj->rb_tree_node, root);
}
/*
* Tmem is managed as a set of tmem_pools with certain attributes, such as
* "ephemeral" vs "persistent". These attributes apply to all tmem_objs
* and all pampds that belong to a tmem_pool. A tmem_pool is created
* or deleted relatively rarely (for example, when a filesystem is
* mounted or unmounted.
*/
/* flush all data from a pool and, optionally, free it */
static void tmem_pool_flush(struct tmem_pool *pool, bool destroy)
{
struct rb_node *rbnode;
struct tmem_obj *obj;
struct tmem_hashbucket *hb = &pool->hashbucket[0];
int i;
BUG_ON(pool == NULL);
for (i = 0; i < TMEM_HASH_BUCKETS; i++, hb++) {
spin_lock(&hb->lock);
rbnode = rb_first(&hb->obj_rb_root);
while (rbnode != NULL) {
obj = rb_entry(rbnode, struct tmem_obj, rb_tree_node);
rbnode = rb_next(rbnode);
tmem_pampd_destroy_all_in_obj(obj);
tmem_obj_free(obj, hb);
(*tmem_hostops.obj_free)(obj, pool);
}
spin_unlock(&hb->lock);
}
if (destroy)
list_del(&pool->pool_list);
}
/*
* A tmem_obj contains a radix-tree-like tree in which the intermediate
* nodes are called tmem_objnodes. (The kernel lib/radix-tree.c implementation
* is very specialized and tuned for specific uses and is not particularly
* suited for use from this code, though some code from the core algorithms has
* been reused, thus the copyright notices below). Each tmem_objnode contains
* a set of pointers which point to either a set of intermediate tmem_objnodes
* or a set of of pampds.
*
* Portions Copyright (C) 2001 Momchil Velikov
* Portions Copyright (C) 2001 Christoph Hellwig
* Portions Copyright (C) 2005 SGI, Christoph Lameter <clameter@sgi.com>
*/
struct tmem_objnode_tree_path {
struct tmem_objnode *objnode;
int offset;
};
/* objnode height_to_maxindex translation */
static unsigned long tmem_objnode_tree_h2max[OBJNODE_TREE_MAX_PATH + 1];
static void tmem_objnode_tree_init(void)
{
unsigned int ht, tmp;
for (ht = 0; ht < ARRAY_SIZE(tmem_objnode_tree_h2max); ht++) {
tmp = ht * OBJNODE_TREE_MAP_SHIFT;
if (tmp >= OBJNODE_TREE_INDEX_BITS)
tmem_objnode_tree_h2max[ht] = ~0UL;
else
tmem_objnode_tree_h2max[ht] =
(~0UL >> (OBJNODE_TREE_INDEX_BITS - tmp - 1)) >> 1;
}
}
static struct tmem_objnode *tmem_objnode_alloc(struct tmem_obj *obj)
{
struct tmem_objnode *objnode;
ASSERT_SENTINEL(obj, OBJ);
BUG_ON(obj->pool == NULL);
ASSERT_SENTINEL(obj->pool, POOL);
objnode = (*tmem_hostops.objnode_alloc)(obj->pool);
if (unlikely(objnode == NULL))
goto out;
objnode->obj = obj;
SET_SENTINEL(objnode, OBJNODE);
memset(&objnode->slots, 0, sizeof(objnode->slots));
objnode->slots_in_use = 0;
obj->objnode_count++;
out:
return objnode;
}
static void tmem_objnode_free(struct tmem_objnode *objnode)
{
struct tmem_pool *pool;
int i;
BUG_ON(objnode == NULL);
for (i = 0; i < OBJNODE_TREE_MAP_SIZE; i++)
BUG_ON(objnode->slots[i] != NULL);
ASSERT_SENTINEL(objnode, OBJNODE);
INVERT_SENTINEL(objnode, OBJNODE);
BUG_ON(objnode->obj == NULL);
ASSERT_SENTINEL(objnode->obj, OBJ);
pool = objnode->obj->pool;
BUG_ON(pool == NULL);
ASSERT_SENTINEL(pool, POOL);
objnode->obj->objnode_count--;
objnode->obj = NULL;
(*tmem_hostops.objnode_free)(objnode, pool);
}
/*
* lookup index in object and return associated pampd (or NULL if not found)
*/
static void **__tmem_pampd_lookup_in_obj(struct tmem_obj *obj, uint32_t index)
{
unsigned int height, shift;
struct tmem_objnode **slot = NULL;
BUG_ON(obj == NULL);
ASSERT_SENTINEL(obj, OBJ);
BUG_ON(obj->pool == NULL);
ASSERT_SENTINEL(obj->pool, POOL);
height = obj->objnode_tree_height;
if (index > tmem_objnode_tree_h2max[obj->objnode_tree_height])
goto out;
if (height == 0 && obj->objnode_tree_root) {
slot = &obj->objnode_tree_root;
goto out;
}
shift = (height-1) * OBJNODE_TREE_MAP_SHIFT;
slot = &obj->objnode_tree_root;
while (height > 0) {
if (*slot == NULL)
goto out;
slot = (struct tmem_objnode **)
((*slot)->slots +
((index >> shift) & OBJNODE_TREE_MAP_MASK));
shift -= OBJNODE_TREE_MAP_SHIFT;
height--;
}
out:
return slot != NULL ? (void **)slot : NULL;
}
static void *tmem_pampd_lookup_in_obj(struct tmem_obj *obj, uint32_t index)
{
struct tmem_objnode **slot;
slot = (struct tmem_objnode **)__tmem_pampd_lookup_in_obj(obj, index);
return slot != NULL ? *slot : NULL;
}
static void *tmem_pampd_replace_in_obj(struct tmem_obj *obj, uint32_t index,
void *new_pampd)
{
struct tmem_objnode **slot;
void *ret = NULL;
slot = (struct tmem_objnode **)__tmem_pampd_lookup_in_obj(obj, index);
if ((slot != NULL) && (*slot != NULL)) {
void *old_pampd = *(void **)slot;
*(void **)slot = new_pampd;
(*tmem_pamops.free)(old_pampd, obj->pool, NULL, 0);
ret = new_pampd;
}
return ret;
}
static int tmem_pampd_add_to_obj(struct tmem_obj *obj, uint32_t index,
void *pampd)
{
int ret = 0;
struct tmem_objnode *objnode = NULL, *newnode, *slot;
unsigned int height, shift;
int offset = 0;
/* if necessary, extend the tree to be higher */
if (index > tmem_objnode_tree_h2max[obj->objnode_tree_height]) {
height = obj->objnode_tree_height + 1;
if (index > tmem_objnode_tree_h2max[height])
while (index > tmem_objnode_tree_h2max[height])
height++;
if (obj->objnode_tree_root == NULL) {
obj->objnode_tree_height = height;
goto insert;
}
do {
newnode = tmem_objnode_alloc(obj);
if (!newnode) {
ret = -ENOMEM;
goto out;
}
newnode->slots[0] = obj->objnode_tree_root;
newnode->slots_in_use = 1;
obj->objnode_tree_root = newnode;
obj->objnode_tree_height++;
} while (height > obj->objnode_tree_height);
}
insert:
slot = obj->objnode_tree_root;
height = obj->objnode_tree_height;
shift = (height-1) * OBJNODE_TREE_MAP_SHIFT;
while (height > 0) {
if (slot == NULL) {
/* add a child objnode. */
slot = tmem_objnode_alloc(obj);
if (!slot) {
ret = -ENOMEM;
goto out;
}
if (objnode) {
objnode->slots[offset] = slot;
objnode->slots_in_use++;
} else
obj->objnode_tree_root = slot;
}
/* go down a level */
offset = (index >> shift) & OBJNODE_TREE_MAP_MASK;
objnode = slot;
slot = objnode->slots[offset];
shift -= OBJNODE_TREE_MAP_SHIFT;
height--;
}
BUG_ON(slot != NULL);
if (objnode) {
objnode->slots_in_use++;
objnode->slots[offset] = pampd;
} else
obj->objnode_tree_root = pampd;
obj->pampd_count++;
out:
return ret;
}
static void *tmem_pampd_delete_from_obj(struct tmem_obj *obj, uint32_t index)
{
struct tmem_objnode_tree_path path[OBJNODE_TREE_MAX_PATH + 1];
struct tmem_objnode_tree_path *pathp = path;
struct tmem_objnode *slot = NULL;
unsigned int height, shift;
int offset;
BUG_ON(obj == NULL);
ASSERT_SENTINEL(obj, OBJ);
BUG_ON(obj->pool == NULL);
ASSERT_SENTINEL(obj->pool, POOL);
height = obj->objnode_tree_height;
if (index > tmem_objnode_tree_h2max[height])
goto out;
slot = obj->objnode_tree_root;
if (height == 0 && obj->objnode_tree_root) {
obj->objnode_tree_root = NULL;
goto out;
}
shift = (height - 1) * OBJNODE_TREE_MAP_SHIFT;
pathp->objnode = NULL;
do {
if (slot == NULL)
goto out;
pathp++;
offset = (index >> shift) & OBJNODE_TREE_MAP_MASK;
pathp->offset = offset;
pathp->objnode = slot;
slot = slot->slots[offset];
shift -= OBJNODE_TREE_MAP_SHIFT;
height--;
} while (height > 0);
if (slot == NULL)
goto out;
while (pathp->objnode) {
pathp->objnode->slots[pathp->offset] = NULL;
pathp->objnode->slots_in_use--;
if (pathp->objnode->slots_in_use) {
if (pathp->objnode == obj->objnode_tree_root) {
while (obj->objnode_tree_height > 0 &&
obj->objnode_tree_root->slots_in_use == 1 &&
obj->objnode_tree_root->slots[0]) {
struct tmem_objnode *to_free =
obj->objnode_tree_root;
obj->objnode_tree_root =
to_free->slots[0];
obj->objnode_tree_height--;
to_free->slots[0] = NULL;
to_free->slots_in_use = 0;
tmem_objnode_free(to_free);
}
}
goto out;
}
tmem_objnode_free(pathp->objnode); /* 0 slots used, free it */
pathp--;
}
obj->objnode_tree_height = 0;
obj->objnode_tree_root = NULL;
out:
if (slot != NULL)
obj->pampd_count--;
BUG_ON(obj->pampd_count < 0);
return slot;
}
/* recursively walk the objnode_tree destroying pampds and objnodes */
static void tmem_objnode_node_destroy(struct tmem_obj *obj,
struct tmem_objnode *objnode,
unsigned int ht)
{
int i;
if (ht == 0)
return;
for (i = 0; i < OBJNODE_TREE_MAP_SIZE; i++) {
if (objnode->slots[i]) {
if (ht == 1) {
obj->pampd_count--;
(*tmem_pamops.free)(objnode->slots[i],
obj->pool, NULL, 0);
objnode->slots[i] = NULL;
continue;
}
tmem_objnode_node_destroy(obj, objnode->slots[i], ht-1);
tmem_objnode_free(objnode->slots[i]);
objnode->slots[i] = NULL;
}
}
}
static void tmem_pampd_destroy_all_in_obj(struct tmem_obj *obj)
{
if (obj->objnode_tree_root == NULL)
return;
if (obj->objnode_tree_height == 0) {
obj->pampd_count--;
(*tmem_pamops.free)(obj->objnode_tree_root, obj->pool, NULL, 0);
} else {
tmem_objnode_node_destroy(obj, obj->objnode_tree_root,
obj->objnode_tree_height);
tmem_objnode_free(obj->objnode_tree_root);
obj->objnode_tree_height = 0;
}
obj->objnode_tree_root = NULL;
(*tmem_pamops.free_obj)(obj->pool, obj);
}
/*
* Tmem is operated on by a set of well-defined actions:
* "put", "get", "flush", "flush_object", "new pool" and "destroy pool".
* (The tmem ABI allows for subpages and exchanges but these operations
* are not included in this implementation.)
*
* These "tmem core" operations are implemented in the following functions.
*/
/*
* "Put" a page, e.g. copy a page from the kernel into newly allocated
* PAM space (if such space is available). Tmem_put is complicated by
* a corner case: What if a page with matching handle already exists in
* tmem? To guarantee coherency, one of two actions is necessary: Either
* the data for the page must be overwritten, or the page must be
* "flushed" so that the data is not accessible to a subsequent "get".
* Since these "duplicate puts" are relatively rare, this implementation
* always flushes for simplicity.
*/
int tmem_put(struct tmem_pool *pool, struct tmem_oid *oidp, uint32_t index,
char *data, size_t size, bool raw, bool ephemeral)
{
struct tmem_obj *obj = NULL, *objfound = NULL, *objnew = NULL;
void *pampd = NULL, *pampd_del = NULL;
int ret = -ENOMEM;
struct tmem_hashbucket *hb;
hb = &pool->hashbucket[tmem_oid_hash(oidp)];
spin_lock(&hb->lock);
obj = objfound = tmem_obj_find(hb, oidp);
if (obj != NULL) {
pampd = tmem_pampd_lookup_in_obj(objfound, index);
if (pampd != NULL) {
/* if found, is a dup put, flush the old one */
pampd_del = tmem_pampd_delete_from_obj(obj, index);
BUG_ON(pampd_del != pampd);
(*tmem_pamops.free)(pampd, pool, oidp, index);
if (obj->pampd_count == 0) {
objnew = obj;
objfound = NULL;
}
pampd = NULL;
}
} else {
obj = objnew = (*tmem_hostops.obj_alloc)(pool);
if (unlikely(obj == NULL)) {
ret = -ENOMEM;
goto out;
}
tmem_obj_init(obj, hb, pool, oidp);
}
BUG_ON(obj == NULL);
BUG_ON(((objnew != obj) && (objfound != obj)) || (objnew == objfound));
pampd = (*tmem_pamops.create)(data, size, raw, ephemeral,
obj->pool, &obj->oid, index);
if (unlikely(pampd == NULL))
goto free;
ret = tmem_pampd_add_to_obj(obj, index, pampd);
if (unlikely(ret == -ENOMEM))
/* may have partially built objnode tree ("stump") */
goto delete_and_free;
goto out;
delete_and_free:
(void)tmem_pampd_delete_from_obj(obj, index);
free:
if (pampd)
(*tmem_pamops.free)(pampd, pool, NULL, 0);
if (objnew) {
tmem_obj_free(objnew, hb);
(*tmem_hostops.obj_free)(objnew, pool);
}
out:
spin_unlock(&hb->lock);
return ret;
}
/*
* "Get" a page, e.g. if one can be found, copy the tmem page with the
* matching handle from PAM space to the kernel. By tmem definition,
* when a "get" is successful on an ephemeral page, the page is "flushed",
* and when a "get" is successful on a persistent page, the page is retained
* in tmem. Note that to preserve
* coherency, "get" can never be skipped if tmem contains the data.
* That is, if a get is done with a certain handle and fails, any
* subsequent "get" must also fail (unless of course there is a
* "put" done with the same handle).
*/
int tmem_get(struct tmem_pool *pool, struct tmem_oid *oidp, uint32_t index,
char *data, size_t *size, bool raw, int get_and_free)
{
struct tmem_obj *obj;
void *pampd;
bool ephemeral = is_ephemeral(pool);
int ret = -1;
struct tmem_hashbucket *hb;
bool free = (get_and_free == 1) || ((get_and_free == 0) && ephemeral);
bool lock_held = false;
hb = &pool->hashbucket[tmem_oid_hash(oidp)];
spin_lock(&hb->lock);
lock_held = true;
obj = tmem_obj_find(hb, oidp);
if (obj == NULL)
goto out;
if (free)
pampd = tmem_pampd_delete_from_obj(obj, index);
else
pampd = tmem_pampd_lookup_in_obj(obj, index);
if (pampd == NULL)
goto out;
if (free) {
if (obj->pampd_count == 0) {
tmem_obj_free(obj, hb);
(*tmem_hostops.obj_free)(obj, pool);
obj = NULL;
}
}
if (tmem_pamops.is_remote(pampd)) {
lock_held = false;
spin_unlock(&hb->lock);
}
if (free)
ret = (*tmem_pamops.get_data_and_free)(
data, size, raw, pampd, pool, oidp, index);
else
ret = (*tmem_pamops.get_data)(
data, size, raw, pampd, pool, oidp, index);
if (ret < 0)
goto out;
ret = 0;
out:
if (lock_held)
spin_unlock(&hb->lock);
return ret;
}
/*
* If a page in tmem matches the handle, "flush" this page from tmem such
* that any subsequent "get" does not succeed (unless, of course, there
* was another "put" with the same handle).
*/
int tmem_flush_page(struct tmem_pool *pool,
struct tmem_oid *oidp, uint32_t index)
{
struct tmem_obj *obj;
void *pampd;
int ret = -1;
struct tmem_hashbucket *hb;
hb = &pool->hashbucket[tmem_oid_hash(oidp)];
spin_lock(&hb->lock);
obj = tmem_obj_find(hb, oidp);
if (obj == NULL)
goto out;
pampd = tmem_pampd_delete_from_obj(obj, index);
if (pampd == NULL)
goto out;
(*tmem_pamops.free)(pampd, pool, oidp, index);
if (obj->pampd_count == 0) {
tmem_obj_free(obj, hb);
(*tmem_hostops.obj_free)(obj, pool);
}
ret = 0;
out:
spin_unlock(&hb->lock);
return ret;
}
/*
* If a page in tmem matches the handle, replace the page so that any
* subsequent "get" gets the new page. Returns 0 if
* there was a page to replace, else returns -1.
*/
int tmem_replace(struct tmem_pool *pool, struct tmem_oid *oidp,
uint32_t index, void *new_pampd)
{
struct tmem_obj *obj;
int ret = -1;
struct tmem_hashbucket *hb;
hb = &pool->hashbucket[tmem_oid_hash(oidp)];
spin_lock(&hb->lock);
obj = tmem_obj_find(hb, oidp);
if (obj == NULL)
goto out;
new_pampd = tmem_pampd_replace_in_obj(obj, index, new_pampd);
ret = (*tmem_pamops.replace_in_obj)(new_pampd, obj);
out:
spin_unlock(&hb->lock);
return ret;
}
/*
* "Flush" all pages in tmem matching this oid.
*/
int tmem_flush_object(struct tmem_pool *pool, struct tmem_oid *oidp)
{
struct tmem_obj *obj;
struct tmem_hashbucket *hb;
int ret = -1;
hb = &pool->hashbucket[tmem_oid_hash(oidp)];
spin_lock(&hb->lock);
obj = tmem_obj_find(hb, oidp);
if (obj == NULL)
goto out;
tmem_pampd_destroy_all_in_obj(obj);
tmem_obj_free(obj, hb);
(*tmem_hostops.obj_free)(obj, pool);
ret = 0;
out:
spin_unlock(&hb->lock);
return ret;
}
/*
* "Flush" all pages (and tmem_objs) from this tmem_pool and disable
* all subsequent access to this tmem_pool.
*/
int tmem_destroy_pool(struct tmem_pool *pool)
{
int ret = -1;
if (pool == NULL)
goto out;
tmem_pool_flush(pool, 1);
ret = 0;
out:
return ret;
}
static LIST_HEAD(tmem_global_pool_list);
/*
* Create a new tmem_pool with the provided flag and return
* a pool id provided by the tmem host implementation.
*/
void tmem_new_pool(struct tmem_pool *pool, uint32_t flags)
{
int persistent = flags & TMEM_POOL_PERSIST;
int shared = flags & TMEM_POOL_SHARED;
struct tmem_hashbucket *hb = &pool->hashbucket[0];
int i;
for (i = 0; i < TMEM_HASH_BUCKETS; i++, hb++) {
hb->obj_rb_root = RB_ROOT;
spin_lock_init(&hb->lock);
}
INIT_LIST_HEAD(&pool->pool_list);
atomic_set(&pool->obj_count, 0);
SET_SENTINEL(pool, POOL);
list_add_tail(&pool->pool_list, &tmem_global_pool_list);
pool->persistent = persistent;
pool->shared = shared;
}
drivers/staging/zcache/tmem.h 已删除 100644 → 0
浏览文件 @ d178a07c
/*
* tmem.h
*
* Transcendent memory
*
* Copyright (c) 2009-2011, Dan Magenheimer, Oracle Corp.
*/
#ifndef _TMEM_H_
#define _TMEM_H_
#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/hash.h>
#include <linux/atomic.h>
/*
* These are pre-defined by the Xen<->Linux ABI
*/
#define TMEM_PUT_PAGE 4
#define TMEM_GET_PAGE 5
#define TMEM_FLUSH_PAGE 6
#define TMEM_FLUSH_OBJECT 7
#define TMEM_POOL_PERSIST 1
#define TMEM_POOL_SHARED 2
#define TMEM_POOL_PRECOMPRESSED 4
#define TMEM_POOL_PAGESIZE_SHIFT 4
#define TMEM_POOL_PAGESIZE_MASK 0xf
#define TMEM_POOL_RESERVED_BITS 0x00ffff00
/*
* sentinels have proven very useful for debugging but can be removed
* or disabled before final merge.
*/
#define SENTINELS
#ifdef SENTINELS
#define DECL_SENTINEL uint32_t sentinel;
#define SET_SENTINEL(_x, _y) (_x->sentinel = _y##_SENTINEL)
#define INVERT_SENTINEL(_x, _y) (_x->sentinel = ~_y##_SENTINEL)
#define ASSERT_SENTINEL(_x, _y) WARN_ON(_x->sentinel != _y##_SENTINEL)
#define ASSERT_INVERTED_SENTINEL(_x, _y) WARN_ON(_x->sentinel != ~_y##_SENTINEL)
#else
#define DECL_SENTINEL
#define SET_SENTINEL(_x, _y) do { } while (0)
#define INVERT_SENTINEL(_x, _y) do { } while (0)
#define ASSERT_SENTINEL(_x, _y) do { } while (0)
#define ASSERT_INVERTED_SENTINEL(_x, _y) do { } while (0)
#endif
#define ASSERT_SPINLOCK(_l) lockdep_assert_held(_l)
/*
* A pool is the highest-level data structure managed by tmem and
* usually corresponds to a large independent set of pages such as
* a filesystem. Each pool has an id, and certain attributes and counters.
* It also contains a set of hash buckets, each of which contains an rbtree
* of objects and a lock to manage concurrency within the pool.
*/
#define TMEM_HASH_BUCKET_BITS 8
#define TMEM_HASH_BUCKETS (1<<TMEM_HASH_BUCKET_BITS)
struct tmem_hashbucket {
struct rb_root obj_rb_root;
spinlock_t lock;
};
struct tmem_pool {
void *client; /* "up" for some clients, avoids table lookup */
struct list_head pool_list;
uint32_t pool_id;
bool persistent;
bool shared;
atomic_t obj_count;
atomic_t refcount;
struct tmem_hashbucket hashbucket[TMEM_HASH_BUCKETS];
DECL_SENTINEL
};
#define is_persistent(_p) (_p->persistent)
#define is_ephemeral(_p) (!(_p->persistent))
/*
* An object id ("oid") is large: 192-bits (to ensure, for example, files
* in a modern filesystem can be uniquely identified).
*/
struct tmem_oid {
uint64_t oid[3];
};
static inline void tmem_oid_set_invalid(struct tmem_oid *oidp)
{
oidp->oid[0] = oidp->oid[1] = oidp->oid[2] = -1UL;
}
static inline bool tmem_oid_valid(struct tmem_oid *oidp)
{
return oidp->oid[0] != -1UL || oidp->oid[1] != -1UL ||
oidp->oid[2] != -1UL;
}
static inline int tmem_oid_compare(struct tmem_oid *left,
struct tmem_oid *right)
{
int ret;
if (left->oid[2] == right->oid[2]) {
if (left->oid[1] == right->oid[1]) {
if (left->oid[0] == right->oid[0])
ret = 0;
else if (left->oid[0] < right->oid[0])
ret = -1;
else
return 1;
} else if (left->oid[1] < right->oid[1])
ret = -1;
else
ret = 1;
} else if (left->oid[2] < right->oid[2])
ret = -1;
else
ret = 1;
return ret;
}
static inline unsigned tmem_oid_hash(struct tmem_oid *oidp)
{
return hash_long(oidp->oid[0] ^ oidp->oid[1] ^ oidp->oid[2],
TMEM_HASH_BUCKET_BITS);
}
/*
* A tmem_obj contains an identifier (oid), pointers to the parent
* pool and the rb_tree to which it belongs, counters, and an ordered
* set of pampds, structured in a radix-tree-like tree. The intermediate
* nodes of the tree are called tmem_objnodes.
*/
struct tmem_objnode;
struct tmem_obj {
struct tmem_oid oid;
struct tmem_pool *pool;
struct rb_node rb_tree_node;
struct tmem_objnode *objnode_tree_root;
unsigned int objnode_tree_height;
unsigned long objnode_count;
long pampd_count;
void *extra; /* for private use by pampd implementation */
DECL_SENTINEL
};
#define OBJNODE_TREE_MAP_SHIFT 6
#define OBJNODE_TREE_MAP_SIZE (1UL << OBJNODE_TREE_MAP_SHIFT)
#define OBJNODE_TREE_MAP_MASK (OBJNODE_TREE_MAP_SIZE-1)
#define OBJNODE_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long))
#define OBJNODE_TREE_MAX_PATH \
(OBJNODE_TREE_INDEX_BITS/OBJNODE_TREE_MAP_SHIFT + 2)
struct tmem_objnode {
struct tmem_obj *obj;
DECL_SENTINEL
void *slots[OBJNODE_TREE_MAP_SIZE];
unsigned int slots_in_use;
};
/* pampd abstract datatype methods provided by the PAM implementation */
struct tmem_pamops {
void *(*create)(char *, size_t, bool, int,
struct tmem_pool *, struct tmem_oid *, uint32_t);
int (*get_data)(char *, size_t *, bool, void *, struct tmem_pool *,
struct tmem_oid *, uint32_t);
int (*get_data_and_free)(char *, size_t *, bool, void *,
struct tmem_pool *, struct tmem_oid *,
uint32_t);
void (*free)(void *, struct tmem_pool *, struct tmem_oid *, uint32_t);
void (*free_obj)(struct tmem_pool *, struct tmem_obj *);
bool (*is_remote)(void *);
void (*new_obj)(struct tmem_obj *);
int (*replace_in_obj)(void *, struct tmem_obj *);
};
extern void tmem_register_pamops(struct tmem_pamops *m);
/* memory allocation methods provided by the host implementation */
struct tmem_hostops {
struct tmem_obj *(*obj_alloc)(struct tmem_pool *);
void (*obj_free)(struct tmem_obj *, struct tmem_pool *);
struct tmem_objnode *(*objnode_alloc)(struct tmem_pool *);
void (*objnode_free)(struct tmem_objnode *, struct tmem_pool *);
};
extern void tmem_register_hostops(struct tmem_hostops *m);
/* core tmem accessor functions */
extern int tmem_put(struct tmem_pool *, struct tmem_oid *, uint32_t index,
char *, size_t, bool, bool);
extern int tmem_get(struct tmem_pool *, struct tmem_oid *, uint32_t index,
char *, size_t *, bool, int);
extern int tmem_replace(struct tmem_pool *, struct tmem_oid *, uint32_t index,
void *);
extern int tmem_flush_page(struct tmem_pool *, struct tmem_oid *,
uint32_t index);
extern int tmem_flush_object(struct tmem_pool *, struct tmem_oid *);
extern int tmem_destroy_pool(struct tmem_pool *);
extern void tmem_new_pool(struct tmem_pool *, uint32_t);
#endif /* _TMEM_H */
drivers/staging/zcache/zcache-main.c 已删除 100644 → 0
浏览文件 @ d178a07c
/*
* zcache.c
*
* Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp.
* Copyright (c) 2010,2011, Nitin Gupta
*
* Zcache provides an in-kernel "host implementation" for transcendent memory
* and, thus indirectly, for cleancache and frontswap. Zcache includes two
* page-accessible memory [1] interfaces, both utilizing the crypto compression
* API:
* 1) "compression buddies" ("zbud") is used for ephemeral pages
* 2) zsmalloc is used for persistent pages.
* Xvmalloc (based on the TLSF allocator) has very low fragmentation
* so maximizes space efficiency, while zbud allows pairs (and potentially,
* in the future, more than a pair of) compressed pages to be closely linked
* so that reclaiming can be done via the kernel's physical-page-oriented
* "shrinker" interface.
*
* [1] For a definition of page-accessible memory (aka PAM), see:
* http://marc.info/?l=linux-mm&m=127811271605009
*/
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/highmem.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/math64.h>
#include <linux/crypto.h>
#include <linux/string.h>
#include <linux/idr.h>
#include "tmem.h"
#include "../zsmalloc/zsmalloc.h"
#ifdef CONFIG_CLEANCACHE
#include <linux/cleancache.h>
#endif
#ifdef CONFIG_FRONTSWAP
#include <linux/frontswap.h>
#endif
#if 0
/* this is more aggressive but may cause other problems? */
#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
#else
#define ZCACHE_GFP_MASK \
(__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
#endif
#define MAX_CLIENTS 16
#define LOCAL_CLIENT ((uint16_t)-1)
MODULE_LICENSE("GPL");
struct zcache_client {
struct idr tmem_pools;
struct zs_pool *zspool;
bool allocated;
atomic_t refcount;
};
static struct zcache_client zcache_host;
static struct zcache_client zcache_clients[MAX_CLIENTS];
static inline uint16_t get_client_id_from_client(struct zcache_client *cli)
{
BUG_ON(cli == NULL);
if (cli == &zcache_host)
return LOCAL_CLIENT;
return cli - &zcache_clients[0];
}
static struct zcache_client *get_zcache_client(uint16_t cli_id)
{
if (cli_id == LOCAL_CLIENT)
return &zcache_host;
if ((unsigned int)cli_id < MAX_CLIENTS)
return &zcache_clients[cli_id];
return NULL;
}
static inline bool is_local_client(struct zcache_client *cli)
{
return cli == &zcache_host;
}
/* crypto API for zcache */
#define ZCACHE_COMP_NAME_SZ CRYPTO_MAX_ALG_NAME
static char zcache_comp_name[ZCACHE_COMP_NAME_SZ];
static struct crypto_comp * __percpu *zcache_comp_pcpu_tfms;
enum comp_op {
ZCACHE_COMPOP_COMPRESS,
ZCACHE_COMPOP_DECOMPRESS
};
static inline int zcache_comp_op(enum comp_op op,
const u8 *src, unsigned int slen,
u8 *dst, unsigned int *dlen)
{
struct crypto_comp *tfm;
int ret;
BUG_ON(!zcache_comp_pcpu_tfms);
tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, get_cpu());
BUG_ON(!tfm);
switch (op) {
case ZCACHE_COMPOP_COMPRESS:
ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
break;
case ZCACHE_COMPOP_DECOMPRESS:
ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
break;
default:
ret = -EINVAL;
}
put_cpu();
return ret;
}
/**********
* Compression buddies ("zbud") provides for packing two (or, possibly
* in the future, more) compressed ephemeral pages into a single "raw"
* (physical) page and tracking them with data structures so that
* the raw pages can be easily reclaimed.
*
* A zbud page ("zbpg") is an aligned page containing a list_head,
* a lock, and two "zbud headers". The remainder of the physical
* page is divided up into aligned 64-byte "chunks" which contain
* the compressed data for zero, one, or two zbuds. Each zbpg
* resides on: (1) an "unused list" if it has no zbuds; (2) a
* "buddied" list if it is fully populated with two zbuds; or
* (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
* the one unbuddied zbud uses. The data inside a zbpg cannot be
* read or written unless the zbpg's lock is held.
*/
#define ZBH_SENTINEL 0x43214321
#define ZBPG_SENTINEL 0xdeadbeef
#define ZBUD_MAX_BUDS 2
struct zbud_hdr {
uint16_t client_id;
uint16_t pool_id;
struct tmem_oid oid;
uint32_t index;
uint16_t size; /* compressed size in bytes, zero means unused */
DECL_SENTINEL
};
struct zbud_page {
struct list_head bud_list;
spinlock_t lock;
struct zbud_hdr buddy[ZBUD_MAX_BUDS];
DECL_SENTINEL
/* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
};
#define CHUNK_SHIFT 6
#define CHUNK_SIZE (1 << CHUNK_SHIFT)
#define CHUNK_MASK (~(CHUNK_SIZE-1))
#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
CHUNK_MASK) >> CHUNK_SHIFT)
#define MAX_CHUNK (NCHUNKS-1)
static struct {
struct list_head list;
unsigned count;
} zbud_unbuddied[NCHUNKS];
/* list N contains pages with N chunks USED and NCHUNKS-N unused */
/* element 0 is never used but optimizing that isn't worth it */
static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
struct list_head zbud_buddied_list;
static unsigned long zcache_zbud_buddied_count;
/* protects the buddied list and all unbuddied lists */
static DEFINE_SPINLOCK(zbud_budlists_spinlock);
static LIST_HEAD(zbpg_unused_list);
static unsigned long zcache_zbpg_unused_list_count;
/* protects the unused page list */
static DEFINE_SPINLOCK(zbpg_unused_list_spinlock);
static atomic_t zcache_zbud_curr_raw_pages;
static atomic_t zcache_zbud_curr_zpages;
static unsigned long zcache_zbud_curr_zbytes;
static unsigned long zcache_zbud_cumul_zpages;
static unsigned long zcache_zbud_cumul_zbytes;
static unsigned long zcache_compress_poor;
static unsigned long zcache_mean_compress_poor;
/* forward references */
static void *zcache_get_free_page(void);
static void zcache_free_page(void *p);
/*
* zbud helper functions
*/
static inline unsigned zbud_max_buddy_size(void)
{
return MAX_CHUNK << CHUNK_SHIFT;
}
static inline unsigned zbud_size_to_chunks(unsigned size)
{
BUG_ON(size == 0 || size > zbud_max_buddy_size());
return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
}
static inline int zbud_budnum(struct zbud_hdr *zh)
{
unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
struct zbud_page *zbpg = NULL;
unsigned budnum = -1U;
int i;
for (i = 0; i < ZBUD_MAX_BUDS; i++)
if (offset == offsetof(typeof(*zbpg), buddy[i])) {
budnum = i;
break;
}
BUG_ON(budnum == -1U);
return budnum;
}
static char *zbud_data(struct zbud_hdr *zh, unsigned size)
{
struct zbud_page *zbpg;
char *p;
unsigned budnum;
ASSERT_SENTINEL(zh, ZBH);
budnum = zbud_budnum(zh);
BUG_ON(size == 0 || size > zbud_max_buddy_size());
zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
ASSERT_SPINLOCK(&zbpg->lock);
p = (char *)zbpg;
if (budnum == 0)
p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
CHUNK_MASK);
else if (budnum == 1)
p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
return p;
}
/*
* zbud raw page management
*/
static struct zbud_page *zbud_alloc_raw_page(void)
{
struct zbud_page *zbpg = NULL;
struct zbud_hdr *zh0, *zh1;
bool recycled = 0;
/* if any pages on the zbpg list, use one */
spin_lock(&zbpg_unused_list_spinlock);
if (!list_empty(&zbpg_unused_list)) {
zbpg = list_first_entry(&zbpg_unused_list,
struct zbud_page, bud_list);
list_del_init(&zbpg->bud_list);
zcache_zbpg_unused_list_count--;
recycled = 1;
}
spin_unlock(&zbpg_unused_list_spinlock);
if (zbpg == NULL)
/* none on zbpg list, try to get a kernel page */
zbpg = zcache_get_free_page();
if (likely(zbpg != NULL)) {
INIT_LIST_HEAD(&zbpg->bud_list);
zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
spin_lock_init(&zbpg->lock);
if (recycled) {
ASSERT_INVERTED_SENTINEL(zbpg, ZBPG);
SET_SENTINEL(zbpg, ZBPG);
BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
} else {
atomic_inc(&zcache_zbud_curr_raw_pages);
INIT_LIST_HEAD(&zbpg->bud_list);
SET_SENTINEL(zbpg, ZBPG);
zh0->size = 0; zh1->size = 0;
tmem_oid_set_invalid(&zh0->oid);
tmem_oid_set_invalid(&zh1->oid);
}
}
return zbpg;
}
static void zbud_free_raw_page(struct zbud_page *zbpg)
{
struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
ASSERT_SENTINEL(zbpg, ZBPG);
BUG_ON(!list_empty(&zbpg->bud_list));
ASSERT_SPINLOCK(&zbpg->lock);
BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
INVERT_SENTINEL(zbpg, ZBPG);
spin_unlock(&zbpg->lock);
spin_lock(&zbpg_unused_list_spinlock);
list_add(&zbpg->bud_list, &zbpg_unused_list);
zcache_zbpg_unused_list_count++;
spin_unlock(&zbpg_unused_list_spinlock);
}
/*
* core zbud handling routines
*/
static unsigned zbud_free(struct zbud_hdr *zh)
{
unsigned size;
ASSERT_SENTINEL(zh, ZBH);
BUG_ON(!tmem_oid_valid(&zh->oid));
size = zh->size;
BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
zh->size = 0;
tmem_oid_set_invalid(&zh->oid);
INVERT_SENTINEL(zh, ZBH);
zcache_zbud_curr_zbytes -= size;
atomic_dec(&zcache_zbud_curr_zpages);
return size;
}
static void zbud_free_and_delist(struct zbud_hdr *zh)
{
unsigned chunks;
struct zbud_hdr *zh_other;
unsigned budnum = zbud_budnum(zh), size;
struct zbud_page *zbpg =
container_of(zh, struct zbud_page, buddy[budnum]);
spin_lock(&zbud_budlists_spinlock);
spin_lock(&zbpg->lock);
if (list_empty(&zbpg->bud_list)) {
/* ignore zombie page... see zbud_evict_pages() */
spin_unlock(&zbpg->lock);
spin_unlock(&zbud_budlists_spinlock);
return;
}
size = zbud_free(zh);
ASSERT_SPINLOCK(&zbpg->lock);
zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
if (zh_other->size == 0) { /* was unbuddied: unlist and free */
chunks = zbud_size_to_chunks(size) ;
BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
list_del_init(&zbpg->bud_list);
zbud_unbuddied[chunks].count--;
spin_unlock(&zbud_budlists_spinlock);
zbud_free_raw_page(zbpg);
} else { /* was buddied: move remaining buddy to unbuddied list */
chunks = zbud_size_to_chunks(zh_other->size) ;
list_del_init(&zbpg->bud_list);
zcache_zbud_buddied_count--;
list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
zbud_unbuddied[chunks].count++;
spin_unlock(&zbud_budlists_spinlock);
spin_unlock(&zbpg->lock);
}
}
static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id,
struct tmem_oid *oid,
uint32_t index, struct page *page,
void *cdata, unsigned size)
{
struct zbud_hdr *zh0, *zh1, *zh = NULL;
struct zbud_page *zbpg = NULL, *ztmp;
unsigned nchunks;
char *to;
int i, found_good_buddy = 0;
nchunks = zbud_size_to_chunks(size) ;
for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
spin_lock(&zbud_budlists_spinlock);
if (!list_empty(&zbud_unbuddied[i].list)) {
list_for_each_entry_safe(zbpg, ztmp,
&zbud_unbuddied[i].list, bud_list) {
if (spin_trylock(&zbpg->lock)) {
found_good_buddy = i;
goto found_unbuddied;
}
}
}
spin_unlock(&zbud_budlists_spinlock);
}
/* didn't find a good buddy, try allocating a new page */
zbpg = zbud_alloc_raw_page();
if (unlikely(zbpg == NULL))
goto out;
/* ok, have a page, now compress the data before taking locks */
spin_lock(&zbud_budlists_spinlock);
spin_lock(&zbpg->lock);
list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
zbud_unbuddied[nchunks].count++;
zh = &zbpg->buddy[0];
goto init_zh;
found_unbuddied:
ASSERT_SPINLOCK(&zbpg->lock);
zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
ASSERT_SENTINEL(zh0, ZBH);
zh = zh1;
} else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
ASSERT_SENTINEL(zh1, ZBH);
zh = zh0;
} else
BUG();
list_del_init(&zbpg->bud_list);
zbud_unbuddied[found_good_buddy].count--;
list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
zcache_zbud_buddied_count++;
init_zh:
SET_SENTINEL(zh, ZBH);
zh->size = size;
zh->index = index;
zh->oid = *oid;
zh->pool_id = pool_id;
zh->client_id = client_id;
to = zbud_data(zh, size);
memcpy(to, cdata, size);
spin_unlock(&zbpg->lock);
spin_unlock(&zbud_budlists_spinlock);
zbud_cumul_chunk_counts[nchunks]++;
atomic_inc(&zcache_zbud_curr_zpages);
zcache_zbud_cumul_zpages++;
zcache_zbud_curr_zbytes += size;
zcache_zbud_cumul_zbytes += size;
out:
return zh;
}
static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
{
struct zbud_page *zbpg;
unsigned budnum = zbud_budnum(zh);
unsigned int out_len = PAGE_SIZE;
char *to_va, *from_va;
unsigned size;
int ret = 0;
zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
spin_lock(&zbpg->lock);
if (list_empty(&zbpg->bud_list)) {
/* ignore zombie page... see zbud_evict_pages() */
ret = -EINVAL;
goto out;
}
ASSERT_SENTINEL(zh, ZBH);
BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
to_va = kmap_atomic(page);
size = zh->size;
from_va = zbud_data(zh, size);
ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, from_va, size,
to_va, &out_len);
BUG_ON(ret);
BUG_ON(out_len != PAGE_SIZE);
kunmap_atomic(to_va);
out:
spin_unlock(&zbpg->lock);
return ret;
}
/*
* The following routines handle shrinking of ephemeral pages by evicting
* pages "least valuable" first.
*/
static unsigned long zcache_evicted_raw_pages;
static unsigned long zcache_evicted_buddied_pages;
static unsigned long zcache_evicted_unbuddied_pages;
static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
uint16_t poolid);
static void zcache_put_pool(struct tmem_pool *pool);
/*
* Flush and free all zbuds in a zbpg, then free the pageframe
*/
static void zbud_evict_zbpg(struct zbud_page *zbpg)
{
struct zbud_hdr *zh;
int i, j;
uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS];
uint32_t index[ZBUD_MAX_BUDS];
struct tmem_oid oid[ZBUD_MAX_BUDS];
struct tmem_pool *pool;
ASSERT_SPINLOCK(&zbpg->lock);
BUG_ON(!list_empty(&zbpg->bud_list));
for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
zh = &zbpg->buddy[i];
if (zh->size) {
client_id[j] = zh->client_id;
pool_id[j] = zh->pool_id;
oid[j] = zh->oid;
index[j] = zh->index;
j++;
zbud_free(zh);
}
}
spin_unlock(&zbpg->lock);
for (i = 0; i < j; i++) {
pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
if (pool != NULL) {
tmem_flush_page(pool, &oid[i], index[i]);
zcache_put_pool(pool);
}
}
ASSERT_SENTINEL(zbpg, ZBPG);
spin_lock(&zbpg->lock);
zbud_free_raw_page(zbpg);
}
/*
* Free nr pages. This code is funky because we want to hold the locks
* protecting various lists for as short a time as possible, and in some
* circumstances the list may change asynchronously when the list lock is
* not held. In some cases we also trylock not only to avoid waiting on a
* page in use by another cpu, but also to avoid potential deadlock due to
* lock inversion.
*/
static void zbud_evict_pages(int nr)
{
struct zbud_page *zbpg;
int i;
/* first try freeing any pages on unused list */
retry_unused_list:
spin_lock_bh(&zbpg_unused_list_spinlock);
if (!list_empty(&zbpg_unused_list)) {
/* can't walk list here, since it may change when unlocked */
zbpg = list_first_entry(&zbpg_unused_list,
struct zbud_page, bud_list);
list_del_init(&zbpg->bud_list);
zcache_zbpg_unused_list_count--;
atomic_dec(&zcache_zbud_curr_raw_pages);
spin_unlock_bh(&zbpg_unused_list_spinlock);
zcache_free_page(zbpg);
zcache_evicted_raw_pages++;
if (--nr <= 0)
goto out;
goto retry_unused_list;
}
spin_unlock_bh(&zbpg_unused_list_spinlock);
/* now try freeing unbuddied pages, starting with least space avail */
for (i = 0; i < MAX_CHUNK; i++) {
retry_unbud_list_i:
spin_lock_bh(&zbud_budlists_spinlock);
if (list_empty(&zbud_unbuddied[i].list)) {
spin_unlock_bh(&zbud_budlists_spinlock);
continue;
}
list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
if (unlikely(!spin_trylock(&zbpg->lock)))
continue;
list_del_init(&zbpg->bud_list);
zbud_unbuddied[i].count--;
spin_unlock(&zbud_budlists_spinlock);
zcache_evicted_unbuddied_pages++;
/* want budlists unlocked when doing zbpg eviction */
zbud_evict_zbpg(zbpg);
local_bh_enable();
if (--nr <= 0)
goto out;
goto retry_unbud_list_i;
}
spin_unlock_bh(&zbud_budlists_spinlock);
}
/* as a last resort, free buddied pages */
retry_bud_list:
spin_lock_bh(&zbud_budlists_spinlock);
if (list_empty(&zbud_buddied_list)) {
spin_unlock_bh(&zbud_budlists_spinlock);
goto out;
}
list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
if (unlikely(!spin_trylock(&zbpg->lock)))
continue;
list_del_init(&zbpg->bud_list);
zcache_zbud_buddied_count--;
spin_unlock(&zbud_budlists_spinlock);
zcache_evicted_buddied_pages++;
/* want budlists unlocked when doing zbpg eviction */
zbud_evict_zbpg(zbpg);
local_bh_enable();
if (--nr <= 0)
goto out;
goto retry_bud_list;
}
spin_unlock_bh(&zbud_budlists_spinlock);
out:
return;
}
static void __init zbud_init(void)
{
int i;
INIT_LIST_HEAD(&zbud_buddied_list);
for (i = 0; i < NCHUNKS; i++)
INIT_LIST_HEAD(&zbud_unbuddied[i].list);
}
#ifdef CONFIG_SYSFS
/*
* These sysfs routines show a nice distribution of how many zbpg's are
* currently (and have ever been placed) in each unbuddied list. It's fun
* to watch but can probably go away before final merge.
*/
static int zbud_show_unbuddied_list_counts(char *buf)
{
int i;
char *p = buf;
for (i = 0; i < NCHUNKS; i++)
p += sprintf(p, "%u ", zbud_unbuddied[i].count);
return p - buf;
}
static int zbud_show_cumul_chunk_counts(char *buf)
{
unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
unsigned long total_chunks_lte_42 = 0;
char *p = buf;
for (i = 0; i < NCHUNKS; i++) {
p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
chunks += zbud_cumul_chunk_counts[i];
total_chunks += zbud_cumul_chunk_counts[i];
sum_total_chunks += i * zbud_cumul_chunk_counts[i];
if (i == 21)
total_chunks_lte_21 = total_chunks;
if (i == 32)
total_chunks_lte_32 = total_chunks;
if (i == 42)
total_chunks_lte_42 = total_chunks;
}
p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
chunks == 0 ? 0 : sum_total_chunks / chunks);
return p - buf;
}
#endif
/**********
* This "zv" PAM implementation combines the slab-based zsmalloc
* with the crypto compression API to maximize the amount of data that can
* be packed into a physical page.
*
* Zv represents a PAM page with the index and object (plus a "size" value
* necessary for decompression) immediately preceding the compressed data.
*/
#define ZVH_SENTINEL 0x43214321
struct zv_hdr {
uint32_t pool_id;
struct tmem_oid oid;
uint32_t index;
size_t size;
DECL_SENTINEL
};
/* rudimentary policy limits */
/* total number of persistent pages may not exceed this percentage */
static unsigned int zv_page_count_policy_percent = 75;
/*
* byte count defining poor compression; pages with greater zsize will be
* rejected
*/
static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
/*
* byte count defining poor *mean* compression; pages with greater zsize
* will be rejected until sufficient better-compressed pages are accepted
* driving the mean below this threshold
*/
static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
static atomic_t zv_curr_dist_counts[NCHUNKS];
static atomic_t zv_cumul_dist_counts[NCHUNKS];
static unsigned long zv_create(struct zs_pool *pool, uint32_t pool_id,
struct tmem_oid *oid, uint32_t index,
void *cdata, unsigned clen)
{
struct zv_hdr *zv;
u32 size = clen + sizeof(struct zv_hdr);
int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
unsigned long handle = 0;
BUG_ON(!irqs_disabled());
BUG_ON(chunks >= NCHUNKS);
handle = zs_malloc(pool, size);
if (!handle)
goto out;
atomic_inc(&zv_curr_dist_counts[chunks]);
atomic_inc(&zv_cumul_dist_counts[chunks]);
zv = zs_map_object(pool, handle, ZS_MM_WO);
zv->index = index;
zv->oid = *oid;
zv->pool_id = pool_id;
zv->size = clen;
SET_SENTINEL(zv, ZVH);
memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
zs_unmap_object(pool, handle);
out:
return handle;
}
static void zv_free(struct zs_pool *pool, unsigned long handle)
{
unsigned long flags;
struct zv_hdr *zv;
uint16_t size;
int chunks;
zv = zs_map_object(pool, handle, ZS_MM_RW);
ASSERT_SENTINEL(zv, ZVH);
size = zv->size + sizeof(struct zv_hdr);
INVERT_SENTINEL(zv, ZVH);
zs_unmap_object(pool, handle);
chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
BUG_ON(chunks >= NCHUNKS);
atomic_dec(&zv_curr_dist_counts[chunks]);
local_irq_save(flags);
zs_free(pool, handle);
local_irq_restore(flags);
}
static void zv_decompress(struct page *page, unsigned long handle)
{
unsigned int clen = PAGE_SIZE;
char *to_va;
int ret;
struct zv_hdr *zv;
zv = zs_map_object(zcache_host.zspool, handle, ZS_MM_RO);
BUG_ON(zv->size == 0);
ASSERT_SENTINEL(zv, ZVH);
to_va = kmap_atomic(page);
ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, (char *)zv + sizeof(*zv),
zv->size, to_va, &clen);
kunmap_atomic(to_va);
zs_unmap_object(zcache_host.zspool, handle);
BUG_ON(ret);
BUG_ON(clen != PAGE_SIZE);
}
#ifdef CONFIG_SYSFS
/*
* show a distribution of compression stats for zv pages.
*/
static int zv_curr_dist_counts_show(char *buf)
{
unsigned long i, n, chunks = 0, sum_total_chunks = 0;
char *p = buf;
for (i = 0; i < NCHUNKS; i++) {
n = atomic_read(&zv_curr_dist_counts[i]);
p += sprintf(p, "%lu ", n);
chunks += n;
sum_total_chunks += i * n;
}
p += sprintf(p, "mean:%lu\n",
chunks == 0 ? 0 : sum_total_chunks / chunks);
return p - buf;
}
static int zv_cumul_dist_counts_show(char *buf)
{
unsigned long i, n, chunks = 0, sum_total_chunks = 0;
char *p = buf;
for (i = 0; i < NCHUNKS; i++) {
n = atomic_read(&zv_cumul_dist_counts[i]);
p += sprintf(p, "%lu ", n);
chunks += n;
sum_total_chunks += i * n;
}
p += sprintf(p, "mean:%lu\n",
chunks == 0 ? 0 : sum_total_chunks / chunks);
return p - buf;
}
/*
* setting zv_max_zsize via sysfs causes all persistent (e.g. swap)
* pages that don't compress to less than this value (including metadata
* overhead) to be rejected. We don't allow the value to get too close
* to PAGE_SIZE.
*/
static ssize_t zv_max_zsize_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", zv_max_zsize);
}
static ssize_t zv_max_zsize_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned long val;
int err;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = kstrtoul(buf, 10, &val);
if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
return -EINVAL;
zv_max_zsize = val;
return count;
}
/*
* setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap)
* pages that don't compress to less than this value (including metadata
* overhead) to be rejected UNLESS the mean compression is also smaller
* than this value. In other words, we are load-balancing-by-zsize the
* accepted pages. Again, we don't allow the value to get too close
* to PAGE_SIZE.
*/
static ssize_t zv_max_mean_zsize_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", zv_max_mean_zsize);
}
static ssize_t zv_max_mean_zsize_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned long val;
int err;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = kstrtoul(buf, 10, &val);
if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
return -EINVAL;
zv_max_mean_zsize = val;
return count;
}
/*
* setting zv_page_count_policy_percent via sysfs sets an upper bound of
* persistent (e.g. swap) pages that will be retained according to:
* (zv_page_count_policy_percent * totalram_pages) / 100)
* when that limit is reached, further puts will be rejected (until
* some pages have been flushed). Note that, due to compression,
* this number may exceed 100; it defaults to 75 and we set an
* arbitary limit of 150. A poor choice will almost certainly result
* in OOM's, so this value should only be changed prudently.
*/
static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", zv_page_count_policy_percent);
}
static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned long val;
int err;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = kstrtoul(buf, 10, &val);
if (err || (val == 0) || (val > 150))
return -EINVAL;
zv_page_count_policy_percent = val;
return count;
}
static struct kobj_attribute zcache_zv_max_zsize_attr = {
.attr = { .name = "zv_max_zsize", .mode = 0644 },
.show = zv_max_zsize_show,
.store = zv_max_zsize_store,
};
static struct kobj_attribute zcache_zv_max_mean_zsize_attr = {
.attr = { .name = "zv_max_mean_zsize", .mode = 0644 },
.show = zv_max_mean_zsize_show,
.store = zv_max_mean_zsize_store,
};
static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = {
.attr = { .name = "zv_page_count_policy_percent",
.mode = 0644 },
.show = zv_page_count_policy_percent_show,
.store = zv_page_count_policy_percent_store,
};
#endif
/*
* zcache core code starts here
*/
/* useful stats not collected by cleancache or frontswap */
static unsigned long zcache_flush_total;
static unsigned long zcache_flush_found;
static unsigned long zcache_flobj_total;
static unsigned long zcache_flobj_found;
static unsigned long zcache_failed_eph_puts;
static unsigned long zcache_failed_pers_puts;
/*
* Tmem operations assume the poolid implies the invoking client.
* Zcache only has one client (the kernel itself): LOCAL_CLIENT.
* RAMster has each client numbered by cluster node, and a KVM version
* of zcache would have one client per guest and each client might
* have a poolid==N.
*/
static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
{
struct tmem_pool *pool = NULL;
struct zcache_client *cli = NULL;
cli = get_zcache_client(cli_id);
if (!cli)
goto out;
atomic_inc(&cli->refcount);
pool = idr_find(&cli->tmem_pools, poolid);
if (pool != NULL)
atomic_inc(&pool->refcount);
out:
return pool;
}
static void zcache_put_pool(struct tmem_pool *pool)
{
struct zcache_client *cli = NULL;
if (pool == NULL)
BUG();
cli = pool->client;
atomic_dec(&pool->refcount);
atomic_dec(&cli->refcount);
}
int zcache_new_client(uint16_t cli_id)
{
struct zcache_client *cli;
int ret = -1;
cli = get_zcache_client(cli_id);
if (cli == NULL)
goto out;
if (cli->allocated)
goto out;
cli->allocated = 1;
#ifdef CONFIG_FRONTSWAP
cli->zspool = zs_create_pool("zcache", ZCACHE_GFP_MASK);
if (cli->zspool == NULL)
goto out;
idr_init(&cli->tmem_pools);
#endif
ret = 0;
out:
return ret;
}
/* counters for debugging */
static unsigned long zcache_failed_get_free_pages;
static unsigned long zcache_failed_alloc;
static unsigned long zcache_put_to_flush;
/*
* for now, used named slabs so can easily track usage; later can
* either just use kmalloc, or perhaps add a slab-like allocator
* to more carefully manage total memory utilization
*/
static struct kmem_cache *zcache_objnode_cache;
static struct kmem_cache *zcache_obj_cache;
static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
static unsigned long zcache_curr_obj_count_max;
static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
static unsigned long zcache_curr_objnode_count_max;
/*
* to avoid memory allocation recursion (e.g. due to direct reclaim), we
* preload all necessary data structures so the hostops callbacks never
* actually do a malloc
*/
struct zcache_preload {
void *page;
struct tmem_obj *obj;
int nr;
struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
};
static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
static int zcache_do_preload(struct tmem_pool *pool)
{
struct zcache_preload *kp;
struct tmem_objnode *objnode;
struct tmem_obj *obj;
void *page;
int ret = -ENOMEM;
if (unlikely(zcache_objnode_cache == NULL))
goto out;
if (unlikely(zcache_obj_cache == NULL))
goto out;
/* IRQ has already been disabled. */
kp = &__get_cpu_var(zcache_preloads);
while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
objnode = kmem_cache_alloc(zcache_objnode_cache,
ZCACHE_GFP_MASK);
if (unlikely(objnode == NULL)) {
zcache_failed_alloc++;
goto out;
}
kp->objnodes[kp->nr++] = objnode;
}
if (!kp->obj) {
obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
if (unlikely(obj == NULL)) {
zcache_failed_alloc++;
goto out;
}
kp->obj = obj;
}
if (!kp->page) {
page = (void *)__get_free_page(ZCACHE_GFP_MASK);
if (unlikely(page == NULL)) {
zcache_failed_get_free_pages++;
goto out;
}
kp->page = page;
}
ret = 0;
out:
return ret;
}
static void *zcache_get_free_page(void)
{
struct zcache_preload *kp;
void *page;
kp = &__get_cpu_var(zcache_preloads);
page = kp->page;
BUG_ON(page == NULL);
kp->page = NULL;
return page;
}
static void zcache_free_page(void *p)
{
free_page((unsigned long)p);
}
/*
* zcache implementation for tmem host ops
*/
static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
{
struct tmem_objnode *objnode = NULL;
unsigned long count;
struct zcache_preload *kp;
kp = &__get_cpu_var(zcache_preloads);
if (kp->nr <= 0)
goto out;
objnode = kp->objnodes[kp->nr - 1];
BUG_ON(objnode == NULL);
kp->objnodes[kp->nr - 1] = NULL;
kp->nr--;
count = atomic_inc_return(&zcache_curr_objnode_count);
if (count > zcache_curr_objnode_count_max)
zcache_curr_objnode_count_max = count;
out:
return objnode;
}
static void zcache_objnode_free(struct tmem_objnode *objnode,
struct tmem_pool *pool)
{
atomic_dec(&zcache_curr_objnode_count);
BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
kmem_cache_free(zcache_objnode_cache, objnode);
}
static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
{
struct tmem_obj *obj = NULL;
unsigned long count;
struct zcache_preload *kp;
kp = &__get_cpu_var(zcache_preloads);
obj = kp->obj;
BUG_ON(obj == NULL);
kp->obj = NULL;
count = atomic_inc_return(&zcache_curr_obj_count);
if (count > zcache_curr_obj_count_max)
zcache_curr_obj_count_max = count;
return obj;
}
static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
{
atomic_dec(&zcache_curr_obj_count);
BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
kmem_cache_free(zcache_obj_cache, obj);
}
static struct tmem_hostops zcache_hostops = {
.obj_alloc = zcache_obj_alloc,
.obj_free = zcache_obj_free,
.objnode_alloc = zcache_objnode_alloc,
.objnode_free = zcache_objnode_free,
};
/*
* zcache implementations for PAM page descriptor ops
*/
static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
static unsigned long zcache_curr_eph_pampd_count_max;
static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
static unsigned long zcache_curr_pers_pampd_count_max;
/* forward reference */
static int zcache_compress(struct page *from, void **out_va, unsigned *out_len);
static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
struct tmem_pool *pool, struct tmem_oid *oid,
uint32_t index)
{
void *pampd = NULL, *cdata;
unsigned clen;
int ret;
unsigned long count;
struct page *page = (struct page *)(data);
struct zcache_client *cli = pool->client;
uint16_t client_id = get_client_id_from_client(cli);
unsigned long zv_mean_zsize;
unsigned long curr_pers_pampd_count;
u64 total_zsize;
if (eph) {
ret = zcache_compress(page, &cdata, &clen);
if (ret == 0)
goto out;
if (clen == 0 || clen > zbud_max_buddy_size()) {
zcache_compress_poor++;
goto out;
}
pampd = (void *)zbud_create(client_id, pool->pool_id, oid,
index, page, cdata, clen);
if (pampd != NULL) {
count = atomic_inc_return(&zcache_curr_eph_pampd_count);
if (count > zcache_curr_eph_pampd_count_max)
zcache_curr_eph_pampd_count_max = count;
}
} else {
curr_pers_pampd_count =
atomic_read(&zcache_curr_pers_pampd_count);
if (curr_pers_pampd_count >
(zv_page_count_policy_percent * totalram_pages) / 100)
goto out;
ret = zcache_compress(page, &cdata, &clen);
if (ret == 0)
goto out;
/* reject if compression is too poor */
if (clen > zv_max_zsize) {
zcache_compress_poor++;
goto out;
}
/* reject if mean compression is too poor */
if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
total_zsize = zs_get_total_size_bytes(cli->zspool);
zv_mean_zsize = div_u64(total_zsize,
curr_pers_pampd_count);
if (zv_mean_zsize > zv_max_mean_zsize) {
zcache_mean_compress_poor++;
goto out;
}
}
pampd = (void *)zv_create(cli->zspool, pool->pool_id,
oid, index, cdata, clen);
if (pampd == NULL)
goto out;
count = atomic_inc_return(&zcache_curr_pers_pampd_count);
if (count > zcache_curr_pers_pampd_count_max)
zcache_curr_pers_pampd_count_max = count;
}
out:
return pampd;
}
/*
* fill the pageframe corresponding to the struct page with the data
* from the passed pampd
*/
static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
void *pampd, struct tmem_pool *pool,
struct tmem_oid *oid, uint32_t index)
{
int ret = 0;
BUG_ON(is_ephemeral(pool));
zv_decompress((struct page *)(data), (unsigned long)pampd);
return ret;
}
/*
* fill the pageframe corresponding to the struct page with the data
* from the passed pampd
*/
static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw,
void *pampd, struct tmem_pool *pool,
struct tmem_oid *oid, uint32_t index)
{
BUG_ON(!is_ephemeral(pool));
if (zbud_decompress((struct page *)(data), pampd) < 0)
return -EINVAL;
zbud_free_and_delist((struct zbud_hdr *)pampd);
atomic_dec(&zcache_curr_eph_pampd_count);
return 0;
}
/*
* free the pampd and remove it from any zcache lists
* pampd must no longer be pointed to from any tmem data structures!
*/
static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
struct tmem_oid *oid, uint32_t index)
{
struct zcache_client *cli = pool->client;
if (is_ephemeral(pool)) {
zbud_free_and_delist((struct zbud_hdr *)pampd);
atomic_dec(&zcache_curr_eph_pampd_count);
BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0);
} else {
zv_free(cli->zspool, (unsigned long)pampd);
atomic_dec(&zcache_curr_pers_pampd_count);
BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0);
}
}
static void zcache_pampd_free_obj(struct tmem_pool *pool, struct tmem_obj *obj)
{
}
static void zcache_pampd_new_obj(struct tmem_obj *obj)
{
}
static int zcache_pampd_replace_in_obj(void *pampd, struct tmem_obj *obj)
{
return -1;
}
static bool zcache_pampd_is_remote(void *pampd)
{
return 0;
}
static struct tmem_pamops zcache_pamops = {
.create = zcache_pampd_create,
.get_data = zcache_pampd_get_data,
.get_data_and_free = zcache_pampd_get_data_and_free,
.free = zcache_pampd_free,
.free_obj = zcache_pampd_free_obj,
.new_obj = zcache_pampd_new_obj,
.replace_in_obj = zcache_pampd_replace_in_obj,
.is_remote = zcache_pampd_is_remote,
};
/*
* zcache compression/decompression and related per-cpu stuff
*/
static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
#define ZCACHE_DSTMEM_ORDER 1
static int zcache_compress(struct page *from, void **out_va, unsigned *out_len)
{
int ret = 0;
unsigned char *dmem = __get_cpu_var(zcache_dstmem);
char *from_va;
BUG_ON(!irqs_disabled());
if (unlikely(dmem == NULL))
goto out; /* no buffer or no compressor so can't compress */
*out_len = PAGE_SIZE << ZCACHE_DSTMEM_ORDER;
from_va = kmap_atomic(from);
mb();
ret = zcache_comp_op(ZCACHE_COMPOP_COMPRESS, from_va, PAGE_SIZE, dmem,
out_len);
BUG_ON(ret);
*out_va = dmem;
kunmap_atomic(from_va);
ret = 1;
out:
return ret;
}
static int zcache_comp_cpu_up(int cpu)
{
struct crypto_comp *tfm;
tfm = crypto_alloc_comp(zcache_comp_name, 0, 0);
if (IS_ERR(tfm))
return NOTIFY_BAD;
*per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = tfm;
return NOTIFY_OK;
}
static void zcache_comp_cpu_down(int cpu)
{
struct crypto_comp *tfm;
tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu);
crypto_free_comp(tfm);
*per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = NULL;
}
static int zcache_cpu_notifier(struct notifier_block *nb,
unsigned long action, void *pcpu)
{
int ret, cpu = (long)pcpu;
struct zcache_preload *kp;
switch (action) {
case CPU_UP_PREPARE:
ret = zcache_comp_cpu_up(cpu);
if (ret != NOTIFY_OK) {
pr_err("zcache: can't allocate compressor transform\n");
return ret;
}
per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
GFP_KERNEL | __GFP_REPEAT, ZCACHE_DSTMEM_ORDER);
break;
case CPU_DEAD:
case CPU_UP_CANCELED:
zcache_comp_cpu_down(cpu);
free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
ZCACHE_DSTMEM_ORDER);
per_cpu(zcache_dstmem, cpu) = NULL;
kp = &per_cpu(zcache_preloads, cpu);
while (kp->nr) {
kmem_cache_free(zcache_objnode_cache,
kp->objnodes[kp->nr - 1]);
kp->objnodes[kp->nr - 1] = NULL;
kp->nr--;
}
if (kp->obj) {
kmem_cache_free(zcache_obj_cache, kp->obj);
kp->obj = NULL;
}
if (kp->page) {
free_page((unsigned long)kp->page);
kp->page = NULL;
}
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block zcache_cpu_notifier_block = {
.notifier_call = zcache_cpu_notifier
};
#ifdef CONFIG_SYSFS
#define ZCACHE_SYSFS_RO(_name) \
static ssize_t zcache_##_name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
return sprintf(buf, "%lu\n", zcache_##_name); \
} \
static struct kobj_attribute zcache_##_name##_attr = { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = zcache_##_name##_show, \
}
#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
static ssize_t zcache_##_name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
} \
static struct kobj_attribute zcache_##_name##_attr = { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = zcache_##_name##_show, \
}
#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
static ssize_t zcache_##_name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
return _func(buf); \
} \
static struct kobj_attribute zcache_##_name##_attr = { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = zcache_##_name##_show, \
}
ZCACHE_SYSFS_RO(curr_obj_count_max);
ZCACHE_SYSFS_RO(curr_objnode_count_max);
ZCACHE_SYSFS_RO(flush_total);
ZCACHE_SYSFS_RO(flush_found);
ZCACHE_SYSFS_RO(flobj_total);
ZCACHE_SYSFS_RO(flobj_found);
ZCACHE_SYSFS_RO(failed_eph_puts);
ZCACHE_SYSFS_RO(failed_pers_puts);
ZCACHE_SYSFS_RO(zbud_curr_zbytes);
ZCACHE_SYSFS_RO(zbud_cumul_zpages);
ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
ZCACHE_SYSFS_RO(zbud_buddied_count);
ZCACHE_SYSFS_RO(zbpg_unused_list_count);
ZCACHE_SYSFS_RO(evicted_raw_pages);
ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
ZCACHE_SYSFS_RO(evicted_buddied_pages);
ZCACHE_SYSFS_RO(failed_get_free_pages);
ZCACHE_SYSFS_RO(failed_alloc);
ZCACHE_SYSFS_RO(put_to_flush);
ZCACHE_SYSFS_RO(compress_poor);
ZCACHE_SYSFS_RO(mean_compress_poor);
ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
zbud_show_unbuddied_list_counts);
ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
zbud_show_cumul_chunk_counts);
ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts,
zv_curr_dist_counts_show);
ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts,
zv_cumul_dist_counts_show);
static struct attribute *zcache_attrs[] = {
&zcache_curr_obj_count_attr.attr,
&zcache_curr_obj_count_max_attr.attr,
&zcache_curr_objnode_count_attr.attr,
&zcache_curr_objnode_count_max_attr.attr,
&zcache_flush_total_attr.attr,
&zcache_flobj_total_attr.attr,
&zcache_flush_found_attr.attr,
&zcache_flobj_found_attr.attr,
&zcache_failed_eph_puts_attr.attr,
&zcache_failed_pers_puts_attr.attr,
&zcache_compress_poor_attr.attr,
&zcache_mean_compress_poor_attr.attr,
&zcache_zbud_curr_raw_pages_attr.attr,
&zcache_zbud_curr_zpages_attr.attr,
&zcache_zbud_curr_zbytes_attr.attr,
&zcache_zbud_cumul_zpages_attr.attr,
&zcache_zbud_cumul_zbytes_attr.attr,
&zcache_zbud_buddied_count_attr.attr,
&zcache_zbpg_unused_list_count_attr.attr,
&zcache_evicted_raw_pages_attr.attr,
&zcache_evicted_unbuddied_pages_attr.attr,
&zcache_evicted_buddied_pages_attr.attr,
&zcache_failed_get_free_pages_attr.attr,
&zcache_failed_alloc_attr.attr,
&zcache_put_to_flush_attr.attr,
&zcache_zbud_unbuddied_list_counts_attr.attr,
&zcache_zbud_cumul_chunk_counts_attr.attr,
&zcache_zv_curr_dist_counts_attr.attr,
&zcache_zv_cumul_dist_counts_attr.attr,
&zcache_zv_max_zsize_attr.attr,
&zcache_zv_max_mean_zsize_attr.attr,
&zcache_zv_page_count_policy_percent_attr.attr,
NULL,
};
static struct attribute_group zcache_attr_group = {
.attrs = zcache_attrs,
.name = "zcache",
};
#endif /* CONFIG_SYSFS */
/*
* When zcache is disabled ("frozen"), pools can be created and destroyed,
* but all puts (and thus all other operations that require memory allocation)
* must fail. If zcache is unfrozen, accepts puts, then frozen again,
* data consistency requires all puts while frozen to be converted into
* flushes.
*/
static bool zcache_freeze;
/*
* zcache shrinker interface (only useful for ephemeral pages, so zbud only)
*/
static int shrink_zcache_memory(struct shrinker *shrink,
struct shrink_control *sc)
{
int ret = -1;
int nr = sc->nr_to_scan;
gfp_t gfp_mask = sc->gfp_mask;
if (nr >= 0) {
if (!(gfp_mask & __GFP_FS))
/* does this case really need to be skipped? */
goto out;
zbud_evict_pages(nr);
}
ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
out:
return ret;
}
static struct shrinker zcache_shrinker = {
.shrink = shrink_zcache_memory,
.seeks = DEFAULT_SEEKS,
};
/*
* zcache shims between cleancache/frontswap ops and tmem
*/
static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
uint32_t index, struct page *page)
{
struct tmem_pool *pool;
int ret = -1;
BUG_ON(!irqs_disabled());
pool = zcache_get_pool_by_id(cli_id, pool_id);
if (unlikely(pool == NULL))
goto out;
if (!zcache_freeze && zcache_do_preload(pool) == 0) {
/* preload does preempt_disable on success */
ret = tmem_put(pool, oidp, index, (char *)(page),
PAGE_SIZE, 0, is_ephemeral(pool));
if (ret < 0) {
if (is_ephemeral(pool))
zcache_failed_eph_puts++;
else
zcache_failed_pers_puts++;
}
} else {
zcache_put_to_flush++;
if (atomic_read(&pool->obj_count) > 0)
/* the put fails whether the flush succeeds or not */
(void)tmem_flush_page(pool, oidp, index);
}
zcache_put_pool(pool);
out:
return ret;
}
static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
uint32_t index, struct page *page)
{
struct tmem_pool *pool;
int ret = -1;
unsigned long flags;
size_t size = PAGE_SIZE;
local_irq_save(flags);
pool = zcache_get_pool_by_id(cli_id, pool_id);
if (likely(pool != NULL)) {
if (atomic_read(&pool->obj_count) > 0)
ret = tmem_get(pool, oidp, index, (char *)(page),
&size, 0, is_ephemeral(pool));
zcache_put_pool(pool);
}
local_irq_restore(flags);
return ret;
}
static int zcache_flush_page(int cli_id, int pool_id,
struct tmem_oid *oidp, uint32_t index)
{
struct tmem_pool *pool;
int ret = -1;
unsigned long flags;
local_irq_save(flags);
zcache_flush_total++;
pool = zcache_get_pool_by_id(cli_id, pool_id);
if (likely(pool != NULL)) {
if (atomic_read(&pool->obj_count) > 0)
ret = tmem_flush_page(pool, oidp, index);
zcache_put_pool(pool);
}
if (ret >= 0)
zcache_flush_found++;
local_irq_restore(flags);
return ret;
}
static int zcache_flush_object(int cli_id, int pool_id,
struct tmem_oid *oidp)
{
struct tmem_pool *pool;
int ret = -1;
unsigned long flags;
local_irq_save(flags);
zcache_flobj_total++;
pool = zcache_get_pool_by_id(cli_id, pool_id);
if (likely(pool != NULL)) {
if (atomic_read(&pool->obj_count) > 0)
ret = tmem_flush_object(pool, oidp);
zcache_put_pool(pool);
}
if (ret >= 0)
zcache_flobj_found++;
local_irq_restore(flags);
return ret;
}
static int zcache_destroy_pool(int cli_id, int pool_id)
{
struct tmem_pool *pool = NULL;
struct zcache_client *cli;
int ret = -1;
if (pool_id < 0)
goto out;
cli = get_zcache_client(cli_id);
if (cli == NULL)
goto out;
atomic_inc(&cli->refcount);
pool = idr_find(&cli->tmem_pools, pool_id);
if (pool == NULL)
goto out;
idr_remove(&cli->tmem_pools, pool_id);
/* wait for pool activity on other cpus to quiesce */
while (atomic_read(&pool->refcount) != 0)
;
atomic_dec(&cli->refcount);
local_bh_disable();
ret = tmem_destroy_pool(pool);
local_bh_enable();
kfree(pool);
pr_info("zcache: destroyed pool id=%d, cli_id=%d\n",
pool_id, cli_id);
out:
return ret;
}
static int zcache_new_pool(uint16_t cli_id, uint32_t flags)
{
int poolid = -1;
struct tmem_pool *pool;
struct zcache_client *cli = NULL;
int r;
cli = get_zcache_client(cli_id);
if (cli == NULL)
goto out;
atomic_inc(&cli->refcount);
pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC);
if (pool == NULL) {
pr_info("zcache: pool creation failed: out of memory\n");
goto out;
}
do {
r = idr_pre_get(&cli->tmem_pools, GFP_ATOMIC);
if (r != 1) {
kfree(pool);
pr_info("zcache: pool creation failed: out of memory\n");
goto out;
}
r = idr_get_new(&cli->tmem_pools, pool, &poolid);
} while (r == -EAGAIN);
if (r) {
pr_info("zcache: pool creation failed: error %d\n", r);
kfree(pool);
goto out;
}
atomic_set(&pool->refcount, 0);
pool->client = cli;
pool->pool_id = poolid;
tmem_new_pool(pool, flags);
pr_info("zcache: created %s tmem pool, id=%d, client=%d\n",
flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
poolid, cli_id);
out:
if (cli != NULL)
atomic_dec(&cli->refcount);
return poolid;
}
/**********
* Two kernel functionalities currently can be layered on top of tmem.
* These are "cleancache" which is used as a second-chance cache for clean
* page cache pages; and "frontswap" which is used for swap pages
* to avoid writes to disk. A generic "shim" is provided here for each
* to translate in-kernel semantics to zcache semantics.
*/
#ifdef CONFIG_CLEANCACHE
static void zcache_cleancache_put_page(int pool_id,
struct cleancache_filekey key,
pgoff_t index, struct page *page)
{
u32 ind = (u32) index;
struct tmem_oid oid = *(struct tmem_oid *)&key;
if (likely(ind == index))
(void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index, page);
}
static int zcache_cleancache_get_page(int pool_id,
struct cleancache_filekey key,
pgoff_t index, struct page *page)
{
u32 ind = (u32) index;
struct tmem_oid oid = *(struct tmem_oid *)&key;
int ret = -1;
if (likely(ind == index))
ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index, page);
return ret;
}
static void zcache_cleancache_flush_page(int pool_id,
struct cleancache_filekey key,
pgoff_t index)
{
u32 ind = (u32) index;
struct tmem_oid oid = *(struct tmem_oid *)&key;
if (likely(ind == index))
(void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind);
}
static void zcache_cleancache_flush_inode(int pool_id,
struct cleancache_filekey key)
{
struct tmem_oid oid = *(struct tmem_oid *)&key;
(void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
}
static void zcache_cleancache_flush_fs(int pool_id)
{
if (pool_id >= 0)
(void)zcache_destroy_pool(LOCAL_CLIENT, pool_id);
}
static int zcache_cleancache_init_fs(size_t pagesize)
{
BUG_ON(sizeof(struct cleancache_filekey) !=
sizeof(struct tmem_oid));
BUG_ON(pagesize != PAGE_SIZE);
return zcache_new_pool(LOCAL_CLIENT, 0);
}
static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
{
/* shared pools are unsupported and map to private */
BUG_ON(sizeof(struct cleancache_filekey) !=
sizeof(struct tmem_oid));
BUG_ON(pagesize != PAGE_SIZE);
return zcache_new_pool(LOCAL_CLIENT, 0);
}
static struct cleancache_ops zcache_cleancache_ops = {
.put_page = zcache_cleancache_put_page,
.get_page = zcache_cleancache_get_page,
.invalidate_page = zcache_cleancache_flush_page,
.invalidate_inode = zcache_cleancache_flush_inode,
.invalidate_fs = zcache_cleancache_flush_fs,
.init_shared_fs = zcache_cleancache_init_shared_fs,
.init_fs = zcache_cleancache_init_fs
};
struct cleancache_ops zcache_cleancache_register_ops(void)
{
struct cleancache_ops old_ops =
cleancache_register_ops(&zcache_cleancache_ops);
return old_ops;
}
#endif
#ifdef CONFIG_FRONTSWAP
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
static int zcache_frontswap_poolid = -1;
/*
* Swizzling increases objects per swaptype, increasing tmem concurrency
* for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
* Setting SWIZ_BITS to 27 basically reconstructs the swap entry from
* frontswap_load(), but has side-effects. Hence using 8.
*/
#define SWIZ_BITS 8
#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
#define iswiz(_ind) (_ind >> SWIZ_BITS)
static inline struct tmem_oid oswiz(unsigned type, u32 ind)
{
struct tmem_oid oid = { .oid = { 0 } };
oid.oid[0] = _oswiz(type, ind);
return oid;
}
static int zcache_frontswap_store(unsigned type, pgoff_t offset,
struct page *page)
{
u64 ind64 = (u64)offset;
u32 ind = (u32)offset;
struct tmem_oid oid = oswiz(type, ind);
int ret = -1;
unsigned long flags;
BUG_ON(!PageLocked(page));
if (likely(ind64 == ind)) {
local_irq_save(flags);
ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid,
&oid, iswiz(ind), page);
local_irq_restore(flags);
}
return ret;
}
/* returns 0 if the page was successfully gotten from frontswap, -1 if
* was not present (should never happen!) */
static int zcache_frontswap_load(unsigned type, pgoff_t offset,
struct page *page)
{
u64 ind64 = (u64)offset;
u32 ind = (u32)offset;
struct tmem_oid oid = oswiz(type, ind);
int ret = -1;
BUG_ON(!PageLocked(page));
if (likely(ind64 == ind))
ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid,
&oid, iswiz(ind), page);
return ret;
}
/* flush a single page from frontswap */
static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
{
u64 ind64 = (u64)offset;
u32 ind = (u32)offset;
struct tmem_oid oid = oswiz(type, ind);
if (likely(ind64 == ind))
(void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid,
&oid, iswiz(ind));
}
/* flush all pages from the passed swaptype */
static void zcache_frontswap_flush_area(unsigned type)
{
struct tmem_oid oid;
int ind;
for (ind = SWIZ_MASK; ind >= 0; ind--) {
oid = oswiz(type, ind);
(void)zcache_flush_object(LOCAL_CLIENT,
zcache_frontswap_poolid, &oid);
}
}
static void zcache_frontswap_init(unsigned ignored)
{
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
if (zcache_frontswap_poolid < 0)
zcache_frontswap_poolid =
zcache_new_pool(LOCAL_CLIENT, TMEM_POOL_PERSIST);
}
static struct frontswap_ops zcache_frontswap_ops = {
.store = zcache_frontswap_store,
.load = zcache_frontswap_load,
.invalidate_page = zcache_frontswap_flush_page,
.invalidate_area = zcache_frontswap_flush_area,
.init = zcache_frontswap_init
};
struct frontswap_ops zcache_frontswap_register_ops(void)
{
struct frontswap_ops old_ops =
frontswap_register_ops(&zcache_frontswap_ops);
return old_ops;
}
#endif
/*
* zcache initialization
* NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
* NOTHING HAPPENS!
*/
static int zcache_enabled;
static int __init enable_zcache(char *s)
{
zcache_enabled = 1;
return 1;
}
__setup("zcache", enable_zcache);
/* allow independent dynamic disabling of cleancache and frontswap */
static int use_cleancache = 1;
static int __init no_cleancache(char *s)
{
use_cleancache = 0;
return 1;
}
__setup("nocleancache", no_cleancache);
static int use_frontswap = 1;
static int __init no_frontswap(char *s)
{
use_frontswap = 0;
return 1;
}
__setup("nofrontswap", no_frontswap);
static int __init enable_zcache_compressor(char *s)
{
strncpy(zcache_comp_name, s, ZCACHE_COMP_NAME_SZ);
zcache_enabled = 1;
return 1;
}
__setup("zcache=", enable_zcache_compressor);
static int __init zcache_comp_init(void)
{
int ret = 0;
/* check crypto algorithm */
if (*zcache_comp_name != '\0') {
ret = crypto_has_comp(zcache_comp_name, 0, 0);
if (!ret)
pr_info("zcache: %s not supported\n",
zcache_comp_name);
}
if (!ret)
strcpy(zcache_comp_name, "lzo");
ret = crypto_has_comp(zcache_comp_name, 0, 0);
if (!ret) {
ret = 1;
goto out;
}
pr_info("zcache: using %s compressor\n", zcache_comp_name);
/* alloc percpu transforms */
ret = 0;
zcache_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
if (!zcache_comp_pcpu_tfms)
ret = 1;
out:
return ret;
}
static int __init zcache_init(void)
{
int ret = 0;
#ifdef CONFIG_SYSFS
ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
if (ret) {
pr_err("zcache: can't create sysfs\n");
goto out;
}
#endif /* CONFIG_SYSFS */
if (zcache_enabled) {
unsigned int cpu;
tmem_register_hostops(&zcache_hostops);
tmem_register_pamops(&zcache_pamops);
ret = register_cpu_notifier(&zcache_cpu_notifier_block);
if (ret) {
pr_err("zcache: can't register cpu notifier\n");
goto out;
}
ret = zcache_comp_init();
if (ret) {
pr_err("zcache: compressor initialization failed\n");
goto out;
}
for_each_online_cpu(cpu) {
void *pcpu = (void *)(long)cpu;
zcache_cpu_notifier(&zcache_cpu_notifier_block,
CPU_UP_PREPARE, pcpu);
}
}
zcache_objnode_cache = kmem_cache_create("zcache_objnode",
sizeof(struct tmem_objnode), 0, 0, NULL);
zcache_obj_cache = kmem_cache_create("zcache_obj",
sizeof(struct tmem_obj), 0, 0, NULL);
ret = zcache_new_client(LOCAL_CLIENT);
if (ret) {
pr_err("zcache: can't create client\n");
goto out;
}
#ifdef CONFIG_CLEANCACHE
if (zcache_enabled && use_cleancache) {
struct cleancache_ops old_ops;
zbud_init();
register_shrinker(&zcache_shrinker);
old_ops = zcache_cleancache_register_ops();
pr_info("zcache: cleancache enabled using kernel "
"transcendent memory and compression buddies\n");
if (old_ops.init_fs != NULL)
pr_warning("zcache: cleancache_ops overridden");
}
#endif
#ifdef CONFIG_FRONTSWAP
if (zcache_enabled && use_frontswap) {
struct frontswap_ops old_ops;
old_ops = zcache_frontswap_register_ops();
pr_info("zcache: frontswap enabled using kernel "
"transcendent memory and zsmalloc\n");
if (old_ops.init != NULL)
pr_warning("zcache: frontswap_ops overridden");
}
#endif
out:
return ret;
}
module_init(zcache_init)
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