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Differential D49349

uma: Avoid excessive per-CPU draining
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Authored by des on Mar 14 2025, 12:56 AM.
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kib
gallatin
siderop1_netapp.com
markj
Commits
rG02324ae8279a: uma: Avoid excessive per-CPU draining
rG910535a82a29: uma: Avoid excessive per-CPU draining
rGf506d5af50fc: uma: Avoid excessive per-CPU draining
Summary

After commit 389a3fa693ef, uma_reclaim_domain(UMA_RECLAIM_DRAIN_CPU)
calls uma_zone_reclaim_domain(UMA_RECLAIM_DRAIN_CPU) twice on each zone
in addition to globally draining per-CPU caches. This was unintended
and is unnecessarily slow; in particular, draining per-CPU caches
requires binding to each CPU.

Stop draining per-CPU caches when visiting each zone, just do it once in
pcpu_cache_drain_safe() to minimize the amount of expensive sched_bind()
calls.

Fixes: 389a3fa693ef ("uma: Add UMA_ZONE_UNMANAGED")

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rG FreeBSD src repository
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Event Timeline

markj created this revision.Mar 14 2025, 12:56 AM
Herald added a subscriber: imp. · View Herald TranscriptMar 14 2025, 12:56 AM
markj requested review of this revision.Mar 14 2025, 12:56 AM
Harbormaster completed remote builds in B62910: Diff 152240.Mar 14 2025, 12:56 AM
des accepted this revision.Mar 14 2025, 9:03 AM
This revision is now accepted and ready to land.Mar 14 2025, 9:03 AM
siderop1_netapp.com added a subscriber: siderop1_netapp.com.Mar 14 2025, 1:23 PM
kib accepted this revision.Mar 14 2025, 2:37 PM
gallatin accepted this revision.Mar 14 2025, 5:38 PM
siderop1_netapp.com accepted this revision.Mar 14 2025, 9:21 PM

FWIW, internal testing with an equivalent diff shows the intermittent (~8%) OOM panics seen with 389a3fa693ef are now resolved. Thanks!

kevans added a subscriber: kevans.Mar 15 2025, 4:43 AM
des commandeered this revision.Mar 17 2025, 7:12 PM
des edited reviewers, added: markj; removed: des.

commandeering since @markj is afk

Closed by commit rGf506d5af50fc: uma: Avoid excessive per-CPU draining (authored by markj, committed by des). · Explain WhyMar 17 2025, 7:14 PM
This revision was automatically updated to reflect the committed changes.
des added a commit: rGf506d5af50fc: uma: Avoid excessive per-CPU draining.
des added a commit: rG910535a82a29: uma: Avoid excessive per-CPU draining.Mar 31 2025, 6:36 PM
des added a commit: rG02324ae8279a: uma: Avoid excessive per-CPU draining.

Revision Contents
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PathSize
sys/
vm/
7 lines

Diff 152356

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sys/vm/uma_core.c

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