On Mon, Aug 10, 2020 at 3:18 PM Xunlei Pang <xlp...@linux.alibaba.com> wrote: > > v1->v2: > - Improved changelog and variable naming for PATCH 1~2. > - PATCH3 adds per-cpu counter to avoid performance regression > in concurrent __slab_free(). > > [Testing] > On my 32-cpu 2-socket physical machine: > Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz > perf stat --null --repeat 10 -- hackbench 20 thread 20000 > > == original, no patched > 19.211637055 seconds time elapsed > ( +- 0.57% ) > > == patched with patch1~2 > Performance counter stats for 'hackbench 20 thread 20000' (10 runs): > > 21.731833146 seconds time elapsed > ( +- 0.17% ) > > == patched with patch1~3 > Performance counter stats for 'hackbench 20 thread 20000' (10 runs): > > 19.112106847 seconds time elapsed > ( +- 0.64% ) > > > Xunlei Pang (3): > mm/slub: Introduce two counters for partial objects > mm/slub: Get rid of count_partial() > mm/slub: Use percpu partial free counter > > mm/slab.h | 2 + > mm/slub.c | 124 > +++++++++++++++++++++++++++++++++++++++++++------------------- > 2 files changed, 89 insertions(+), 37 deletions(-)
We probably need to wrap the counters under CONFIG_SLUB_DEBUG because AFAICT all the code that uses them is also wrapped under it. An alternative approach for this patch would be to somehow make the lock in count_partial() more granular, but I don't know how feasible that actually is. Anyway, I am OK with this approach: Reviewed-by: Pekka Enberg <penb...@kernel.org> You still need to convince Christoph, though, because he had objections over this approach. - Pekka
