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SubjectRe: [PATCH 1/2] mm/slub: Introduce two counters for the partial objects
On Tue, 7 Jul 2020, Pekka Enberg wrote:

> On Fri, Jul 3, 2020 at 12:38 PM xunlei <> wrote:
> >
> > On 2020/7/2 PM 7:59, Pekka Enberg wrote:
> > > On Thu, Jul 2, 2020 at 11:32 AM Xunlei Pang <> wrote:
> > >> The node list_lock in count_partial() spend long time iterating
> > >> in case of large amount of partial page lists, which can cause
> > >> thunder herd effect to the list_lock contention, e.g. it cause
> > >> business response-time jitters when accessing "/proc/slabinfo"
> > >> in our production environments.
> > >
> > > Would you have any numbers to share to quantify this jitter? I have no
> >
> > We have HSF RT(High-speed Service Framework Response-Time) monitors, the
> > RT figures fluctuated randomly, then we deployed a tool detecting "irq
> > off" and "preempt off" to dump the culprit's calltrace, capturing the
> > list_lock cost up to 100ms with irq off issued by "ss", this also caused
> > network timeouts.
> Thanks for the follow up. This sounds like a good enough motivation
> for this patch, but please include it in the changelog.

Well this is access via sysfs causing a holdoff. Another way of access to
the same information without adding atomics and counters would be best.

> > I also have no idea what's the standard SLUB benchmark for the
> > regression test, any specific suggestion?
> I don't know what people use these days. When I did benchmarking in
> the past, hackbench and netperf were known to be slab-allocation
> intensive macro-benchmarks. Christoph also had some SLUB
> micro-benchmarks, but I don't think we ever merged them into the tree.

They are still where they have been for the last decade or so. In my git
tree on They were also reworked a couple of times and posted
to linux-mm. There are historical posts going back over the years where
individuals have modified them and used them to create multiple other

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