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[RESEND,v4,0/3] fs/dcache: Track # of negative dentries

Message ID 1544824384-17668-1-git-send-email-longman@redhat.com (mailing list archive)
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Series fs/dcache: Track # of negative dentries | expand

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Waiman Long Dec. 14, 2018, 9:53 p.m. UTC
v3->v4:
  - Drop patch 4 as it is just a minor optimization.
  - Add a cc:stable tag to patch 1.
  - Clean up some comments in patch 3.

 v2->v3:
  - With confirmation that the dummy array in dentry_stat structure
    was never a replacement of a previously used field, patch 3 is now
    reverted back to use one of dummy field as the negative dentry count
    instead of adding a new field.

 v1->v2:
  - Clarify what the new nr_dentry_negative per-cpu counter is tracking
    and open-code the increment and decrement as suggested by Dave Chinner.
  - Append the new nr_dentry_negative count as the 7th element of dentry-state
    instead of replacing one of the dummy entries.
  - Remove patch "fs/dcache: Make negative dentries easier to be
    reclaimed" for now as I need more time to think about what
    to do with it.
  - Add 2 more patches to address issues found while reviewing the
    dentry code.
  - Add another patch to change the conditional branch of
    nr_dentry_negative accounting to conditional move so as to reduce
    the performance impact of the accounting code.

This patchset addresses 2 issues found in the dentry code and adds a
new nr_dentry_negative per-cpu counter to track the total number of
negative dentries in all the LRU lists.

Patch 1 fixes a bug in the accounting of nr_dentry_unused in
shrink_dcache_sb().

Patch 2 removes the ____cacheline_aligned_in_smp tag from super_block
LRU lists.

Patch 3 adds the new nr_dentry_negative per-cpu counter.

Various filesystem related tests were run and no statistically
significant changes in performance outside of the possible noise range
was observed.

Waiman Long (3):
  fs/dcache: Fix incorrect nr_dentry_unused accounting in
    shrink_dcache_sb()
  fs: Don't need to put list_lru into its own cacheline
  fs/dcache: Track & report number of negative dentries

 Documentation/sysctl/fs.txt | 26 ++++++++++++++++----------
 fs/dcache.c                 | 38 +++++++++++++++++++++++++++++++++-----
 include/linux/dcache.h      |  7 ++++---
 include/linux/fs.h          |  9 +++++----
 4 files changed, 58 insertions(+), 22 deletions(-)

Comments

Linus Torvalds Dec. 16, 2018, 7:37 p.m. UTC | #1
On Fri, Dec 14, 2018 at 1:53 PM Waiman Long <longman@redhat.com> wrote:
>
> This patchset addresses 2 issues found in the dentry code and adds a
> new nr_dentry_negative per-cpu counter to track the total number of
> negative dentries in all the LRU lists.

The series looks sane to me. I'm assuming I'll get it either though
-mm or from Al..

            Linus
Waiman Long Jan. 15, 2019, 9:27 p.m. UTC | #2
On 12/16/2018 02:37 PM, Linus Torvalds wrote:
> On Fri, Dec 14, 2018 at 1:53 PM Waiman Long <longman@redhat.com> wrote:
>> This patchset addresses 2 issues found in the dentry code and adds a
>> new nr_dentry_negative per-cpu counter to track the total number of
>> negative dentries in all the LRU lists.
> The series looks sane to me. I'm assuming I'll get it either though
> -mm or from Al..
>
>             Linus

Could anyone pick up this patchset?

Thanks,
Longman
Waiman Long Jan. 30, 2019, 4:40 p.m. UTC | #3
On 01/15/2019 04:27 PM, Waiman Long wrote:
> On 12/16/2018 02:37 PM, Linus Torvalds wrote:
>> On Fri, Dec 14, 2018 at 1:53 PM Waiman Long <longman@redhat.com> wrote:
>>> This patchset addresses 2 issues found in the dentry code and adds a
>>> new nr_dentry_negative per-cpu counter to track the total number of
>>> negative dentries in all the LRU lists.
>> The series looks sane to me. I'm assuming I'll get it either though
>> -mm or from Al..
>>
>>             Linus
> Could anyone pick up this patchset?
>
> Thanks,
> Longman
>
Ping. Will this patch be picked up?

Thanks,
Longman
Linus Torvalds Jan. 30, 2019, 6:35 p.m. UTC | #4
On Wed, Jan 30, 2019 at 8:40 AM Waiman Long <longman@redhat.com> wrote:
>
> Ping. Will this patch be picked up?

Can you re-send the patch-set and I'll just apply it directly since it
seems to be languishing otherwise.

                Linus
Waiman Long Jan. 30, 2019, 6:37 p.m. UTC | #5
On 01/30/2019 01:35 PM, Linus Torvalds wrote:
> On Wed, Jan 30, 2019 at 8:40 AM Waiman Long <longman@redhat.com> wrote:
>> Ping. Will this patch be picked up?
> Can you re-send the patch-set and I'll just apply it directly since it
> seems to be languishing otherwise.
>
>                 Linus

Sure.

Thanks for your help.

-Longman