On Thu, Jul 20, 2023 at 9:59 PM Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx> wrote:
> On Thu, Jul 20, 2023 at 12:01 PM Oliver Sang <oliver.sang@xxxxxxxxx> wrote:
> > > > commit:
> > > > 7bc162d5cc ("Merge branches 'slab/for-6.5/prandom', 'slab/for-6.5/slab_no_merge' and 'slab/for-6.5/slab-deprecate' into slab/for-next")
> > > > a0fd217e6d ("mm/slub: Optimize slub memory usage")
> > > >
> > > > 7bc162d5cc4de5c3 a0fd217e6d6fbd23e91f8796787
> > > > ---------------- ---------------------------
> > > > %stddev %change %stddev
> > > > \ | \
> > > > 222503 ą 86% +108.7% 464342 ą 58% numa-meminfo.node1.Active
> > > > 222459 ą 86% +108.7% 464294 ą 58% numa-meminfo.node1.Active(anon)
> > > > 55573 ą 85% +108.0% 115619 ą 58% numa-vmstat.node1.nr_active_anon
> > > > 55573 ą 85% +108.0% 115618 ą 58% numa-vmstat.node1.nr_zone_active_anon
> > >
> > > I'm quite baffled while reading this.
> > > How did changing slab order calculation double the number of active anon pages?
> > > I doubt two experiments were performed on the same settings.
> >
> > let me introduce our test process.
> >
> > we make sure the tests upon commit and its parent have exact same environment
> > except the kernel difference, and we also make sure the config to build the
> > commit and its parent are identical.
> >
> > we run tests for one commit at least 6 times to make sure the data is stable.
> >
> > such like for this case, we rebuild the commit and its parent's kernel, the
> > config is attached FYI.
Oh I missed the attachments.
I need more time to look more into that, but could you please test
this patch (attached)?
> 0.00 -100.0% 0.00 numa-numastat.node0.interleave_hit
> 646925 ± 26% +25.4% 811509 ± 29% numa-numastat.node0.local_node
> 693386 ± 20% +30.4% 904091 ± 27% numa-numastat.node0.numa_hit
> 46461 ± 81% +102.6% 94126 ± 31% numa-numastat.node0.other_node
> 0.00 -100.0% 0.00 numa-numastat.node1.interleave_hit
> 1571252 ± 18% -14.3% 1346549 ± 13% numa-numastat.node1.local_node
> 1663884 ± 16% -16.3% 1393406 ± 13% numa-numastat.node1.numa_hit
> 92593 ± 39% -49.5% 46769 ± 61% numa-numastat.node1.other_node
After skimming the attachments - started thinking that it is
undesirable to allocate
high order slabs from remote nodes.
From d688270274febf4115c9c28712d8ff08ca2bee1a Mon Sep 17 00:00:00 2001
From: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Date: Thu, 20 Jul 2023 22:29:16 +0900
Subject: [PATCH] mm/slub: do not allocate from remote node to allocate high
order slab
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
---
mm/slub.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/slub.c b/mm/slub.c
index f7940048138c..1f25888d9a41 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2012,7 +2012,7 @@ static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
*/
alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
- alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM;
+ alloc_gfp = ((alloc_gfp | __GFP_THISNODE | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM);
slab = alloc_slab_page(alloc_gfp, node, oo);
if (unlikely(!slab)) {
--
2.41.0
