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  1. 26 6月, 2015 11 次提交
  3. 11 6月, 2015 1 次提交
  5. 06 5月, 2015 1 次提交
  7. 16 4月, 2015 8 次提交
  9. 01 3月, 2015 1 次提交
  11. 13 2月, 2015 8 次提交
    • G
      mm/zpool: add name argument to create zpool · 3eba0c6a
      由 Ganesh Mahendran 提交于 
      Currently the underlay of zpool: zsmalloc/zbud, do not know who creates
them.  There is not a method to let zsmalloc/zbud find which caller they
belong to.

Now we want to add statistics collection in zsmalloc.  We need to name the
debugfs dir for each pool created.  The way suggested by Minchan Kim is to
use a name passed by caller(such as zram) to create the zsmalloc pool.

    /sys/kernel/debug/zsmalloc/zram0

This patch adds an argument `name' to zs_create_pool() and other related
functions.
Signed-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3eba0c6a
    • S
      zram: remove request_queue from struct zram · ee980160
      由 Sergey Senozhatsky 提交于 
      `struct zram' contains both `struct gendisk' and `struct request_queue'.
the latter can be deleted, because zram->disk carries ->queue pointer, and
->queue carries zram pointer:

create_device()
	zram->queue->queuedata = zram
	zram->disk->queue = zram->queue
	zram->disk->private_data = zram

so zram->queue is not needed, we can access all necessary data anyway.
Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ee980160
    • M
      zram: remove init_lock in zram_make_request · 08eee69f
      由 Minchan Kim 提交于 
      Admin could reset zram during I/O operation going on so we have used
zram->init_lock as read-side lock in I/O path to prevent sudden zram
meta freeing.

However, the init_lock is really troublesome.  We can't do call
zram_meta_alloc under init_lock due to lockdep splat because
zram_rw_page is one of the function under reclaim path and hold it as
read_lock while other places in process context hold it as write_lock.
So, we have used allocation out of the lock to avoid lockdep warn but
it's not good for readability and fainally, I met another lockdep splat
between init_lock and cpu_hotplug from kmem_cache_destroy during working
zsmalloc compaction.  :(

Yes, the ideal is to remove horrible init_lock of zram in rw path.  This
patch removes it in rw path and instead, add atomic refcount for meta
lifetime management and completion to free meta in process context.
It's important to free meta in process context because some of resource
destruction needs mutex lock, which could be held if we releases the
resource in reclaim context so it's deadlock, again.

As a bonus, we could remove init_done check in rw path because
zram_meta_get will do a role for it, instead.
Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Ganesh Mahendran <opensource.ganesh@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      08eee69f
    • M
      zram: check bd_openers instead of bd_holders · 2b269ce6
      由 Minchan Kim 提交于 
      bd_holders is increased only when user open the device file as FMODE_EXCL
so if something opens zram0 as !FMODE_EXCL and request I/O while another
user reset zram0, we can see following warning.

  zram0: detected capacity change from 0 to 64424509440
  Buffer I/O error on dev zram0, logical block 180823, lost async page write
  Buffer I/O error on dev zram0, logical block 180824, lost async page write
  Buffer I/O error on dev zram0, logical block 180825, lost async page write
  Buffer I/O error on dev zram0, logical block 180826, lost async page write
  Buffer I/O error on dev zram0, logical block 180827, lost async page write
  Buffer I/O error on dev zram0, logical block 180828, lost async page write
  Buffer I/O error on dev zram0, logical block 180829, lost async page write
  Buffer I/O error on dev zram0, logical block 180830, lost async page write
  Buffer I/O error on dev zram0, logical block 180831, lost async page write
  Buffer I/O error on dev zram0, logical block 180832, lost async page write
  ------------[ cut here ]------------
  WARNING: CPU: 11 PID: 1996 at fs/block_dev.c:57 __blkdev_put+0x1d7/0x210()
  Modules linked in:
  CPU: 11 PID: 1996 Comm: dd Not tainted 3.19.0-rc6-next-20150202+ #1125
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Call Trace:
    dump_stack+0x45/0x57
    warn_slowpath_common+0x8a/0xc0
    warn_slowpath_null+0x1a/0x20
    __blkdev_put+0x1d7/0x210
    blkdev_put+0x50/0x130
    blkdev_close+0x25/0x30
    __fput+0xdf/0x1e0
    ____fput+0xe/0x10
    task_work_run+0xa7/0xe0
    do_notify_resume+0x49/0x60
    int_signal+0x12/0x17
  ---[ end trace 274fbbc5664827d2 ]---

The warning comes from bdev_write_node in blkdev_put path.

   static void bdev_write_inode(struct inode *inode)
   {
        spin_lock(&inode->i_lock);
        while (inode->i_state & I_DIRTY) {
                spin_unlock(&inode->i_lock);
                WARN_ON_ONCE(write_inode_now(inode, true)); <========= here.
                spin_lock(&inode->i_lock);
        }
        spin_unlock(&inode->i_lock);
   }

The reason is dd process encounters I/O fails due to sudden block device
disappear so in filemap_check_errors in __writeback_single_inode returns
-EIO.

If we check bd_openers instead of bd_holders, we could address the
problem.  When I see the brd, it already have used it rather than
bd_holders so although I'm not a expert of block layer, it seems to be
better.

I can make following warning with below simple script.  In addition, I
added msleep(2000) below set_capacity(zram->disk, 0) after applying your
patch to make window huge(Kudos to Ganesh!)

script:

   echo $((60<<30)) > /sys/block/zram0/disksize
   setsid dd if=/dev/zero of=/dev/zram0 &
   sleep 1
   setsid echo 1 > /sys/block/zram0/reset
Signed-off-by: NMinchan Kim <minchan@kernel.org>
Acked-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Ganesh Mahendran <opensource.ganesh@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2b269ce6
    • S
      zram: rework reset and destroy path · a096cafc
      由 Sergey Senozhatsky 提交于 
      We need to return set_capacity(disk, 0) from reset_store() back to
zram_reset_device(), a catch by Ganesh Mahendran.  Potentially, we can
race set_capacity() calls from init and reset paths.

The problem is that zram_reset_device() is also getting called from
zram_exit(), which performs operations in misleading reversed order -- we
first create_device() and then init it, while zram_exit() perform
destroy_device() first and then does zram_reset_device().  This is done to
remove sysfs group before we reset device, so we can continue with device
reset/destruction not being raced by sysfs attr write (f.e.  disksize).

Apart from that, destroy_device() releases zram->disk (but we still have
->disk pointer), so we cannot acces zram->disk in later
zram_reset_device() call, which may cause additional errors in the future.

So, this patch rework and cleanup destroy path.

1) remove several unneeded goto labels in zram_init()

2) factor out zram_init() error path and zram_exit() into
   destroy_devices() function, which takes the number of devices to
   destroy as its argument.

3) remove sysfs group in destroy_devices() first, so we can reorder
   operations -- reset device (as expected) goes before disk destroy and
   queue cleanup.  So we can always access ->disk in zram_reset_device().

4) and, finally, return set_capacity() back under ->init_lock.

[akpm@linux-foundation.org: tweak comment]
Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a096cafc
    • S
      zram: fix umount-reset_store-mount race condition · ba6b17d6
      由 Sergey Senozhatsky 提交于 
      Ganesh Mahendran was the first one who proposed to use bdev->bd_mutex to
avoid ->bd_holders race condition:

        CPU0                            CPU1
umount /* zram->init_done is true */
reset_store()
bdev->bd_holders == 0                   mount
...                                     zram_make_request()
zram_reset_device()

However, his solution required some considerable amount of code movement,
which we can avoid.

Apart from using bdev->bd_mutex in reset_store(), this patch also
simplifies zram_reset_device().

zram_reset_device() has a bool parameter reset_capacity which tells it
whether disk capacity and itself disk should be reset.  There are two
zram_reset_device() callers:

-- zram_exit() passes reset_capacity=false
-- reset_store() passes reset_capacity=true

So we can move reset_capacity-sensitive work out of zram_reset_device()
and perform it unconditionally in reset_store().  This also lets us drop
reset_capacity parameter from zram_reset_device() and pass zram pointer
only.
Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      ba6b17d6
    • G
      zram: free meta table in zram_meta_free · 1fec1172
      由 Ganesh Mahendran 提交于 
      zram_meta_alloc() and zram_meta_free() are a pair.  In
zram_meta_alloc(), meta table is allocated.  So it it better to free it
in zram_meta_free().
Signed-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Acked-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1fec1172
    • S
      zram: clean up zram_meta_alloc() · b8179958
      由 Sergey Senozhatsky 提交于 
      A trivial cleanup of zram_meta_alloc() error handling.
Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b8179958
  13. 14 12月, 2014 4 次提交
  15. 14 11月, 2014 1 次提交
  17. 30 10月, 2014 1 次提交
  19. 10 10月, 2014 4 次提交
    • S
      zram: use notify_free to account all free notifications · 015254da
      由 Sergey Senozhatsky 提交于 
      `notify_free' device attribute accounts the number of slot free
notifications and internally represents the number of zram_free_page()
calls.  Slot free notifications are sent only when device is used as a
swap device, hence `notify_free' is used only for swap devices.  Since
f4659d8e (zram: support REQ_DISCARD) ZRAM handles yet another one
free notification (also via zram_free_page() call) -- REQ_DISCARD
requests, which are sent by a filesystem, whenever some data blocks are
discarded.  However, there is no way to know the number of notifications
in the latter case.

Use `notify_free' to account the number of pages freed by
zram_bio_discard() and zram_slot_free_notify().  Depending on usage
scenario `notify_free' represents:

 a) the number of pages freed because of slot free notifications, which is
   equal to the number of swap_slot_free_notify() calls, so there is no
   behaviour change

 b) the number of pages freed because of REQ_DISCARD notifications
Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Acked-by: NJerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      015254da
    • M
      zram: report maximum used memory · 461a8eee
      由 Minchan Kim 提交于 
      Normally, zram user could get maximum memory usage zram consumed via
polling mem_used_total with sysfs in userspace.

But it has a critical problem because user can miss peak memory usage
during update inverval of polling.  For avoiding that, user should poll it
with shorter interval(ie, 0.0000000001s) with mlocking to avoid page fault
delay when memory pressure is heavy.  It would be troublesome.

This patch adds new knob "mem_used_max" so user could see the maximum
memory usage easily via reading the knob and reset it via "echo 0 >
/sys/block/zram0/mem_used_max".
Signed-off-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NDan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Reviewed-by: NDavid Horner <ds2horner@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      461a8eee
    • M
      zram: zram memory size limitation · 9ada9da9
      由 Minchan Kim 提交于 
      Since zram has no control feature to limit memory usage, it makes hard to
manage system memrory.

This patch adds new knob "mem_limit" via sysfs to set up the a limit so
that zram could fail allocation once it reaches the limit.

In addition, user could change the limit in runtime so that he could
manage the memory more dynamically.

Initial state is no limit so it doesn't break old behavior.

[akpm@linux-foundation.org: fix typo, per Sergey]
Signed-off-by: NMinchan Kim <minchan@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: David Horner <ds2horner@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      9ada9da9
    • M
      zsmalloc: change return value unit of zs_get_total_size_bytes · 722cdc17
      由 Minchan Kim 提交于 
      zs_get_total_size_bytes returns a amount of memory zsmalloc consumed with
*byte unit* but zsmalloc operates *page unit* rather than byte unit so
let's change the API so benefit we could get is that reduce unnecessary
overhead (ie, change page unit with byte unit) in zsmalloc.

Since return type is pages, "zs_get_total_pages" is better than
"zs_get_total_size_bytes".
Signed-off-by: NMinchan Kim <minchan@kernel.org>
Reviewed-by: NDan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: <juno.choi@lge.com>
Cc: <seungho1.park@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: David Horner <ds2horner@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      722cdc17