Any progress on this? The problem addressed by this patch has also made jitters to our online apps which are quite annoying. On Mon, Aug 24, 2020 at 6:05 PM xunlei <xlpang@xxxxxxxxxxxxxxxxx> wrote: > > On 2020/8/20 下午10:02, Pekka Enberg wrote: > > On Mon, Aug 10, 2020 at 3:18 PM Xunlei Pang <xlpang@xxxxxxxxxxxxxxxxx> 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. > > /sys/kernel/slab/***/partial sysfs also uses it, I can wrap it with > CONFIG_SLUB_DEBUG or CONFIG_SYSFS for backward compatibility. > > > > > 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 <penberg@xxxxxxxxxx> > > Thanks! > > > > > You still need to convince Christoph, though, because he had > > objections over this approach. > > Christoph, what do you think, or any better suggestion to address this > *in production* issue? > > > > > - Pekka > >
