Skip to content

K
Kernel

openeuler / Kernel
1 年多 前同步成功

通知 8
Star 0
Fork 0
K
Kernel
切换分支/标签
  1. 22 10月, 2015 7 次提交
  3. 10 10月, 2015 2 次提交
    • C
      blk-mq: remove unused blk_mq_clone_flush_request prototype · 3380f458
      由 Christoph Hellwig 提交于 
      Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>
      3380f458
    • K
      blk-mq: fix waitqueue_active without memory barrier in block/blk-mq-tag.c · 8ee1b7b9
      由 Kosuke Tatsukawa 提交于 
      blk_mq_tag_update_depth() seems to be missing a memory barrier which
might cause the waker to not notice the waiter and fail to send a
wake_up as in the following figure.

	blk_mq_tag_update_depth			bt_get
------------------------------------------------------------------------
if (waitqueue_active(&bs->wait))
/* The CPU might reorder the test for
   the waitqueue up here, before
   prior writes complete */
					prepare_to_wait(&bs->wait, &wait,
					  TASK_UNINTERRUPTIBLE);
					tag = __bt_get(hctx, bt, last_tag,
					  tags);
					/* Value set in bt_update_count not
					   visible yet */
bt_update_count(&tags->bitmap_tags, tdepth);
/* blk_mq_tag_wakeup_all(tags, false); */
 bt = &tags->bitmap_tags;
 wake_index = atomic_read(&bt->wake_index);
					...
					io_schedule();
------------------------------------------------------------------------

This patch adds the missing memory barrier.

I found this issue when I was looking through the linux source code
for places calling waitqueue_active() before wake_up*(), but without
preceding memory barriers, after sending a patch to fix a similar
issue in drivers/tty/n_tty.c  (Details about the original issue can be
found here: https://lkml.org/lkml/2015/9/28/849).
Signed-off-by: NKosuke Tatsukawa <tatsu@ab.jp.nec.com>
Signed-off-by: NJens Axboe <axboe@fb.com>
      8ee1b7b9
  5. 01 10月, 2015 2 次提交
  7. 30 9月, 2015 6 次提交
    • A
      blk-mq: fix deadlock when reading cpu_list · 60de074b
      由 Akinobu Mita 提交于 
      CPU hotplug handling for blk-mq (blk_mq_queue_reinit) acquires
all_q_mutex in blk_mq_queue_reinit_notify() and then removes sysfs
entries by blk_mq_sysfs_unregister().  Removing sysfs entry needs to
be blocked until the active reference of the kernfs_node to be zero.

On the other hand, reading blk_mq_hw_sysfs_cpu sysfs entry (e.g.
/sys/block/nullb0/mq/0/cpu_list) acquires all_q_mutex in
blk_mq_hw_sysfs_cpus_show().

If these happen at the same time, a deadlock can happen.  Because one
can wait for the active reference to be zero with holding all_q_mutex,
and the other tries to acquire all_q_mutex with holding the active
reference.

The reason that all_q_mutex is acquired in blk_mq_hw_sysfs_cpus_show()
is to avoid reading an imcomplete hctx->cpumask.  Since reading sysfs
entry for blk-mq needs to acquire q->sysfs_lock, we can avoid deadlock
and reading an imcomplete hctx->cpumask by protecting q->sysfs_lock
while hctx->cpumask is being updated.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NMing Lei <tom.leiming@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>
      60de074b
    • A
      blk-mq: avoid inserting requests before establishing new mapping · 5778322e
      由 Akinobu Mita 提交于 
      Notifier callbacks for CPU_ONLINE action can be run on the other CPU
than the CPU which was just onlined.  So it is possible for the
process running on the just onlined CPU to insert request and run
hw queue before establishing new mapping which is done by
blk_mq_queue_reinit_notify().

This can cause a problem when the CPU has just been onlined first time
since the request queue was initialized.  At this time ctx->index_hw
for the CPU, which is the index in hctx->ctxs[] for this ctx, is still
zero before blk_mq_queue_reinit_notify() is called by notifier
callbacks for CPU_ONLINE action.

For example, there is a single hw queue (hctx) and two CPU queues
(ctx0 for CPU0, and ctx1 for CPU1).  Now CPU1 is just onlined and
a request is inserted into ctx1->rq_list and set bit0 in pending
bitmap as ctx1->index_hw is still zero.

And then while running hw queue, flush_busy_ctxs() finds bit0 is set
in pending bitmap and tries to retrieve requests in
hctx->ctxs[0]->rq_list.  But htx->ctxs[0] is a pointer to ctx0, so the
request in ctx1->rq_list is ignored.

Fix it by ensuring that new mapping is established before onlined cpu
starts running.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NMing Lei <tom.leiming@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>
      5778322e
    • A
      blk-mq: fix q->mq_usage_counter access race · 0e626368
      由 Akinobu Mita 提交于 
      CPU hotplug handling for blk-mq (blk_mq_queue_reinit) accesses
q->mq_usage_counter while freezing all request queues in all_q_list.
On the other hand, q->mq_usage_counter is deinitialized in
blk_mq_free_queue() before deleting the queue from all_q_list.

So if CPU hotplug event occurs in the window, percpu_ref_kill() is
called with q->mq_usage_counter which has already been marked dead,
and it triggers warning.  Fix it by deleting the queue from all_q_list
earlier than destroying q->mq_usage_counter.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NMing Lei <tom.leiming@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>
      0e626368
    • A
      blk-mq: Fix use after of free q->mq_map · a723bab3
      由 Akinobu Mita 提交于 
      CPU hotplug handling for blk-mq (blk_mq_queue_reinit) updates
q->mq_map by blk_mq_update_queue_map() for all request queues in
all_q_list.  On the other hand, q->mq_map is released before deleting
the queue from all_q_list.

So if CPU hotplug event occurs in the window, invalid memory access
can happen.  Fix it by releasing q->mq_map in blk_mq_release() to make
it happen latter than removal from all_q_list.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Suggested-by: NMing Lei <tom.leiming@gmail.com>
Reviewed-by: NMing Lei <tom.leiming@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>
      a723bab3
    • A
      blk-mq: fix sysfs registration/unregistration race · 4593fdbe
      由 Akinobu Mita 提交于 
      There is a race between cpu hotplug handling and adding/deleting
gendisk for blk-mq, where both are trying to register and unregister
the same sysfs entries.

null_add_dev
    --> blk_mq_init_queue
        --> blk_mq_init_allocated_queue
            --> add to 'all_q_list' (*)
    --> add_disk
        --> blk_register_queue
            --> blk_mq_register_disk (++)

null_del_dev
    --> del_gendisk
        --> blk_unregister_queue
            --> blk_mq_unregister_disk (--)
    --> blk_cleanup_queue
        --> blk_mq_free_queue
            --> del from 'all_q_list' (*)

blk_mq_queue_reinit
    --> blk_mq_sysfs_unregister (-)
    --> blk_mq_sysfs_register (+)

While the request queue is added to 'all_q_list' (*),
blk_mq_queue_reinit() can be called for the queue anytime by CPU
hotplug callback.  But blk_mq_sysfs_unregister (-) and
blk_mq_sysfs_register (+) in blk_mq_queue_reinit must not be called
before blk_mq_register_disk (++) and after blk_mq_unregister_disk (--)
is finished.  Because '/sys/block/*/mq/' is not exists.

There has already been BLK_MQ_F_SYSFS_UP flag in hctx->flags which can
be used to track these sysfs stuff, but it is only fixing this issue
partially.

In order to fix it completely, we just need per-queue flag instead of
per-hctx flag with appropriate locking.  So this introduces
q->mq_sysfs_init_done which is properly protected with all_q_mutex.

Also, we need to ensure that blk_mq_map_swqueue() is called with
all_q_mutex is held.  Since hctx->nr_ctx is reset temporarily and
updated in blk_mq_map_swqueue(), so we should avoid
blk_mq_register_hctx() seeing the temporary hctx->nr_ctx value
in CPU hotplug handling or adding/deleting gendisk .
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NMing Lei <tom.leiming@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>
      4593fdbe
    • A
      blk-mq: avoid setting hctx->tags->cpumask before allocation · 1356aae0
      由 Akinobu Mita 提交于 
      When unmapped hw queue is remapped after CPU topology is changed,
hctx->tags->cpumask has to be set after hctx->tags is setup in
blk_mq_map_swqueue(), otherwise it causes null pointer dereference.

Fixes: f26cdc85 ("blk-mq: Shared tag enhancements")
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>
      1356aae0
  9. 24 9月, 2015 1 次提交
  11. 18 9月, 2015 1 次提交
    • M
      block: fix bounce_end_io · 99451879
      由 Ming Lei 提交于 
      When bio bounce is involved, one new bio and its biovecs are
cloned from the comming bio, which can be one fast-cloned bio
from upper layer(such as dm).

So it is obviously wrong to assume the start index of the coming(
original) bio's io vector is zero, which can be any value between
0 and (bi_max_vecs - 1), especially in case of bio split.

This patch fixes Fedora's booting oops on i386, often with the
following kernel log together:

> [    9.026738] systemd[1]: Switching root.
> [    9.036467] systemd-journald[149]: Received SIGTERM from PID 1
> (systemd).
> [    9.082262] BUG: Bad page state in process kworker/u5:1  pfn:372ac
> [    9.083989] page:f3d32ae0 count:0 mapcount:0 mapping:f2252178
> index:0x16a
> [    9.085755] flags: 0x40020021(locked|lru|mappedtodisk)
> [    9.087284] page dumped because: page still charged to cgroup
> [    9.088772] bad because of flags:
> [    9.089731] flags: 0x21(locked|lru)
> [    9.090818] page->mem_cgroup:f2c3e400
Reported-by: NJosh Boyer <jwboyer@fedoraproject.org>
Tested-by: NAdam Williamson <awilliam@redhat.com>
Cc: Ming Lin <mlin@kernel.org>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NJens Axboe <axboe@fb.com>
      99451879
  13. 17 9月, 2015 1 次提交
    • M
      block: blk-merge: fast-clone bio when splitting rw bios · 52cc6eea
      由 Ming Lei 提交于 
      biovecs has become immutable since v3.13, so it isn't necessary
to allocate biovecs for the new cloned bios, then we can save
one extra biovecs allocation/copy, and the allocation is often
not fixed-length and a bit more expensive.

For example, if the 'max_sectors_kb' of null blk's queue is set
as 16(32 sectors) via sysfs just for making more splits, this patch
can increase throught about ~70% in the sequential read test over
null_blk(direct io, bs: 1M).

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Ming Lin <ming.l@ssi.samsung.com>
Cc: Dongsu Park <dpark@posteo.net>
Signed-off-by: NMing Lei <ming.lei@canonical.com>

This fixes a performance regression introduced by commit 54efd50b,
and allows us to take full advantage of the fact that we have immutable
bio_vecs. Hand applied, as it rejected violently with commit
5014c311.
Signed-off-by: NJens Axboe <axboe@fb.com>
      52cc6eea
  15. 11 9月, 2015 4 次提交
  17. 04 9月, 2015 1 次提交
  19. 03 9月, 2015 1 次提交
  21. 02 9月, 2015 1 次提交
  23. 20 8月, 2015 1 次提交
  25. 19 8月, 2015 12 次提交
    • T
      blkcg: use CGROUP_WEIGHT_* scale for io.weight on the unified hierarchy · 69d7fde5
      由 Tejun Heo 提交于 
      cgroup is trying to make interface consistent across different
controllers.  For weight based resource control, the knob should have
the range [1, 10000] and default to 100.  This patch updates
cfq-iosched so that the weight range conforms.  The internal
calculations have enough range and the widening of the weight range
shouldn't cause any problem.

* blkcg_policy->cpd_bind_fn() is added.  If present, this is invoked
  when blkcg is attached to a hierarchy.

* cfq_cpd_init() is updated to use the new default value on the
  unified hierarchy.

* cfq_cpd_bind() callback is implemented to clear per-blkg configs and
  apply the default config matching the hierarchy type.

* cfqd->root_group->[leaf_]weight initialization in cfq_init_queue()
  is moved into !CONFIG_CFQ_GROUP_IOSCHED block.  cfq_cpd_bind() is
  now responsible for initializing the initial weights when blkcg is
  enabled.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: NJens Axboe <axboe@fb.com>
      69d7fde5
    • T
      blkcg: s/CFQ_WEIGHT_*/CFQ_WEIGHT_LEGACY_*/ · 3ecca629
      由 Tejun Heo 提交于 
      blkcg is gonna switch to cgroup common weight range as defined by
CGROUP_WEIGHT_* on the unified hierarchy.  In preparation, rename
CFQ_WEIGHT_* constants to CFQ_WEIGHT_LEGACY_*.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: NJens Axboe <axboe@fb.com>
      3ecca629
    • T
      blkcg: implement interface for the unified hierarchy · 2ee867dc
      由 Tejun Heo 提交于 
      blkcg interface grew to be the biggest of all controllers and
unfortunately most inconsistent too.  The interface files are
inconsistent with a number of cloes duplicates.  Some files have
recursive variants while others don't.  There's distinction between
normal and leaf weights which isn't intuitive and there are a lot of
stat knobs which don't make much sense outside of debugging and expose
too much implementation details to userland.

In the unified hierarchy, everything is always hierarchical and
internal nodes can't have tasks rendering the two structural issues
twisting the current interface.  The interface has to be updated in a
significant anyway and this is a good chance to revamp it as a whole.
This patch implements blkcg interface for the unified hierarchy.

* (from a previous patch) blkcg is identified by "io" instead of
  "blkio" on the unified hierarchy.  Given that the whole interface is
  updated anyway, the rename shouldn't carry noticeable conversion
  overhead.

* The original interface consisted of 27 files is replaced with the
  following three files.

  blkio.stat	: per-blkcg stats
  blkio.weight	: per-cgroup and per-cgroup-queue weight settings
  blkio.max	: per-cgroup-queue bps and iops max limits

Documentation/cgroups/unified-hierarchy.txt updated accordingly.

v2: blkcg_policy->dfl_cftypes wasn't removed on
    blkcg_policy_unregister() corrupting the cftypes list.  Fixed.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>
      2ee867dc
    • T
      blkcg: misc preparations for unified hierarchy interface · dd165eb3
      由 Tejun Heo 提交于 
      * Export blkg_dev_name()

* Drop unnecessary @cft from __cfq_set_weight().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>
      dd165eb3
    • T
      blkcg: separate out tg_conf_updated() from tg_set_conf() · 69948b07
      由 Tejun Heo 提交于 
      tg_set_conf() is largely consisted of parsing and setting the new
config and the follow-up application and propagation.  This patch
separates out the latter part into tg_conf_updated().  This will be
used to implement interface for the unified hierarchy.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>
      69948b07
    • T
      blkcg: move body parsing from blkg_conf_prep() to its callers · 36aa9e5f
      由 Tejun Heo 提交于 
      Currently, blkg_conf_prep() expects input to be of the following form

 MAJ:MIN NUM

and reads the NUM part into blkg_conf_ctx->v.  This is quite
restrictive and gets in the way in implementing blkcg interface for
the unified hierarchy.  This patch updates blkg_conf_prep() so that it
expects

 MAJ:MIN BODY_STR

where BODY_STR is an arbitrary string.  blkg_conf_ctx->v is replaced
with ->body which is a char pointer pointing to the start of BODY_STR.
Parsing of the body is moved to blkg_conf_prep()'s callers.

To allow using, for example, strsep() on blkg_conf_ctx->val, it is a
non-const pointer and to accommodate that const is dropped from @input
too.

This doesn't cause any behavior changes.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>
      36aa9e5f
    • T
      blkcg: mark existing cftypes as legacy · 880f50e2
      由 Tejun Heo 提交于 
      blkcg is about to grow interface for the unified hierarchy.  Add
legacy to existing cftypes.

* blkcg_policy->cftypes -> blkcg_policy->legacy_cftypes
* blk-cgroup.c:blkcg_files -> blkcg_legacy_files
* cfq-iosched.c:cfq_blkcg_files -> cfq_blkcg_legacy_files
* blk-throttle.c:throtl_files -> throtl_legacy_files

Pure renames.  No functional change.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>
      880f50e2
    • T
      blkcg: rename subsystem name from blkio to io · c165b3e3
      由 Tejun Heo 提交于 
      blkio interface has become messy over time and is currently the
largest.  In addition to the inconsistent naming scheme, it has
multiple stat files which report more or less the same thing, a number
of debug stat files which expose internal details which shouldn't have
been part of the public interface in the first place, recursive and
non-recursive stats and leaf and non-leaf knobs.

Both recursive vs. non-recursive and leaf vs. non-leaf distinctions
don't make any sense on the unified hierarchy as only leaf cgroups can
contain processes.  cgroups is going through a major interface
revision with the unified hierarchy involving significant fundamental
usage changes and given that a significant portion of the interface
doesn't make sense anymore, it's a good time to reorganize the
interface.

As the first step, this patch renames the external visible subsystem
name from "blkio" to "io".  This is more concise, matches the other
two major subsystem names, "cpu" and "memory", and better suited as
blkcg will be involved in anything writeback related too whether an
actual block device is involved or not.

As the subsystem legacy_name is set to "blkio", the only userland
visible change outside the unified hierarchy is that blkcg is reported
as "io" instead of "blkio" in the subsystem initialized message during
boot.  On the unified hierarchy, blkcg now appears as "io".
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>
      c165b3e3
    • T
      blkcg: refine error codes returned during blkcg configuration · 20386ce0
      由 Tejun Heo 提交于 
      blkcg currently returns -EINVAL for most errors which can be pretty
confusing given that the failure modes are quite varied.  Update the
error returns so that

* -EINVAL only for syntactic errors.
* -ERANGE if the value is out of range.
* -ENODEV if the target device can't be found.
* -EOPNOTSUPP if the policy is not enabled on the target device.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>
      20386ce0
    • T
      blkcg: remove unnecessary NULL checks from __cfqg_set_weight_device() · 5332dfc3
      由 Tejun Heo 提交于 
      blkg_to_cfqg() and blkcg_to_cfqgd() on a valid blkg with the policy
enabled are guaranteed to return non-NULL and the counterpart in
blk-throttle doesn't have these checks either.  Remove the spurious
NULL checks.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>
      5332dfc3
    • T
      blkcg: reduce stack usage of blkg_rwstat_recursive_sum() · 3a7faead
      由 Tejun Heo 提交于 
      The recent percpu conversion of blkg_rwstat triggered the following
warning in certain configurations.

 block/blk-cgroup.c:654:1: warning: the frame size of 1360 bytes is larger than 1024 bytes

This is because blkg_rwstat now contains four percpu_counter which can
be pretty big depending on debug options although it shouldn't be a
problem in production configs.  This patch removes one of the two
local blkg_rwstat variables used by blkg_rwstat_recursive_sum() to
reduce stack usage.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Link: http://article.gmane.org/gmane.linux.kernel.cgroups/13835Signed-off-by: NJens Axboe <axboe@fb.com>
      3a7faead
    • T
      blkcg: remove cfqg_stats->sectors · 702747ca
      由 Tejun Heo 提交于 
      cfq_stats->sectors is a blkg_stat which keeps track of the total
number of sectors serviced; however, this can be trivially calculated
from blkcg_gq->stat_bytes.  The only thing necessary is adding up
READs and WRITEs and then dividing by sector size.

Remove cfqg_stats->sectors and make cfq print "sectors" and
"sectors_recursive" from stat_bytes.

While this is a bit more code, it removes duplicate stat allocations
and updates and ensures that the reported stats stay in tune with each
other.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>
      702747ca