Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

ARC: Cache arc_c value during arc_evict() #16605

Merged
merged 1 commit into from
Oct 4, 2024
Merged

ARC: Cache arc_c value during arc_evict() #16605

merged 1 commit into from
Oct 4, 2024

Conversation

amotin
Copy link
Member

@amotin amotin commented Oct 4, 2024

Since arc_evict() run can take some time, arc_c change during it may result in undesired shift in ARC states balance. Primarily in case of arc_c reduction it may cause eviction from MFU data state despite its being below the target already. Instead we should evict as originally planned and if needed do another round after.

Fixes: #16576

How Has This Been Tested?

By @tkittich in #16576.

Types of changes

  • Bug fix (non-breaking change which fixes an issue)
  • New feature (non-breaking change which adds functionality)
  • Performance enhancement (non-breaking change which improves efficiency)
  • Code cleanup (non-breaking change which makes code smaller or more readable)
  • Breaking change (fix or feature that would cause existing functionality to change)
  • Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
  • Documentation (a change to man pages or other documentation)

Checklist:

@amotin amotin requested a review from behlendorf October 4, 2024 13:22
tkittich
tkittich reviewed Oct 4, 2024
View reviewed changes
Copy link
Contributor

@tkittich tkittich left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I believe one more arc_c modification on line 4328 is needed.

@amotin
ARC: Cache arc_c value during arc_evict()
d04269d 
Since arc_evict() run can take some time, arc_c change during it
may result in undesired shift in ARC states balance. Primarily in
case of arc_c reduction it may cause eviction from MFU data state
despite its being below the target already.  Instead we should
evict as originally planned and if needed do another round after.

Fixes:		openzfs#16576
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
@amotin
Copy link
Member Author

amotin commented Oct 4, 2024

@tkittich Thanks. It was a mismerge during commit, I had it my tree. :(

@behlendorf behlendorf added the Status: Accepted Ready to integrate (reviewed, tested) label Oct 4, 2024
@behlendorf behlendorf merged commit 4ebe674 into openzfs:master Oct 4, 2024
17 of 21 checks passed
@amotin amotin deleted the arc_c branch October 7, 2024 13:16
ixhamza pushed a commit to truenas/zfs that referenced this pull request Nov 11, 2024
@amotin @ixhamza
ARC: Cache arc_c value during arc_evict()
c168599 
Since arc_evict() run can take some time, arc_c change during it
may result in undesired shift in ARC states balance. Primarily in
case of arc_c reduction it may cause eviction from MFU data state
despite its being below the target already.  Instead we should
evict as originally planned and if needed do another round after.

Reviewed-by: Theera K. <tkittich@hotmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes openzfs#16576
Closes openzfs#16605
ptr1337 pushed a commit to CachyOS/zfs that referenced this pull request Nov 14, 2024
@amotin @tonyhutter
ARC: Cache arc_c value during arc_evict()
acc8a31 
Since arc_evict() run can take some time, arc_c change during it
may result in undesired shift in ARC states balance. Primarily in
case of arc_c reduction it may cause eviction from MFU data state
despite its being below the target already.  Instead we should
evict as originally planned and if needed do another round after.

Reviewed-by: Theera K. <tkittich@hotmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes openzfs#16576
Closes openzfs#16605
lundman pushed a commit to openzfsonwindows/openzfs that referenced this pull request Jan 26, 2025
@amotin @lundman
ARC: Cache arc_c value during arc_evict()
66aab68 
Since arc_evict() run can take some time, arc_c change during it
may result in undesired shift in ARC states balance. Primarily in
case of arc_c reduction it may cause eviction from MFU data state
despite its being below the target already.  Instead we should
evict as originally planned and if needed do another round after.

Reviewed-by: Theera K. <tkittich@hotmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes openzfs#16576
Closes openzfs#16605
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers

@tkittich tkittich tkittich left review comments

@behlendorf behlendorf behlendorf approved these changes

@gmelikov gmelikov gmelikov approved these changes

Assignees
No one assigned
Labels
Status: Accepted Ready to integrate (reviewed, tested)
Projects
None yet
Milestone
No milestone
Development

Successfully merging this pull request may close these issues.

MRU, MFU don't adapt to their targets
4 participants
@amotin @behlendorf @tkittich @gmelikov