Messages in this thread | | | From | Xunlei Pang <> | Subject | [PATCH v4 0/3] mm/slub: Fix count_partial() problem | Date | Wed, 17 Mar 2021 15:54:49 +0800 |
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count_partial() can hold n->list_lock spinlock for quite long, which makes much trouble to the system. This series eliminate this problem.
v1->v2: - Improved changelog and variable naming for PATCH 1~2. - PATCH3 adds per-cpu counter to avoid performance regression in concurrent __slab_free().
v2->v3: - Changed "page->inuse" to the safe "new.inuse", etc. - Used CONFIG_SLUB_DEBUG and CONFIG_SYSFS condition for new counters. - atomic_long_t -> unsigned long
v3->v4: - introduced new CONFIG_SLUB_DEBUG_PARTIAL to give a chance to be enabled for production use. - Merged PATCH 4 into PATCH 1.
[Testing] There seems might be a little performance impact under extreme __slab_free() concurrent calls according to my tests.
On my 32-cpu 2-socket physical machine: Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz
1) perf stat --null --repeat 10 -- hackbench 20 thread 20000
== original, no patched Performance counter stats for 'hackbench 20 thread 20000' (10 runs):
24.536050899 seconds time elapsed ( +- 0.24% )
Performance counter stats for 'hackbench 20 thread 20000' (10 runs):
24.588049142 seconds time elapsed ( +- 0.35% )
== patched with patch1~4 Performance counter stats for 'hackbench 20 thread 20000' (10 runs):
24.670892273 seconds time elapsed ( +- 0.29% )
Performance counter stats for 'hackbench 20 thread 20000' (10 runs):
24.746755689 seconds time elapsed ( +- 0.21% )
2) perf stat --null --repeat 10 -- hackbench 32 thread 20000
== original, no patched Performance counter stats for 'hackbench 32 thread 20000' (10 runs):
39.784911855 seconds time elapsed ( +- 0.14% )
Performance counter stats for 'hackbench 32 thread 20000' (10 runs):
39.868687608 seconds time elapsed ( +- 0.19% )
== patched with patch1~4 Performance counter stats for 'hackbench 32 thread 20000' (10 runs):
39.681273015 seconds time elapsed ( +- 0.21% )
Performance counter stats for 'hackbench 32 thread 20000' (10 runs):
39.681238459 seconds time elapsed ( +- 0.09% )
Xunlei Pang (3): mm/slub: Introduce two counters for partial objects percpu: Export per_cpu_sum() mm/slub: Get rid of count_partial()
include/linux/percpu-defs.h | 10 ++++ init/Kconfig | 13 +++++ kernel/locking/percpu-rwsem.c | 10 ---- mm/slab.h | 6 ++ mm/slub.c | 129 +++++++++++++++++++++++++++++------------- 5 files changed, 120 insertions(+), 48 deletions(-)
-- 1.8.3.1
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