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
[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 (4):
mm/slub: Introduce two counters for partial objects
mm/slub: Get rid of count_partial()
percpu: Export per_cpu_sum()
mm/slub: Use percpu partial free counter
include/linux/percpu-defs.h | 10 ++++
kernel/locking/percpu-rwsem.c | 10 ----
mm/slab.h | 4 ++
mm/slub.c | 120 +++++++++++++++++++++++++++++-------------
4 files changed, 97 insertions(+), 47 deletions(-)
--
1.8.3.1
