Re: [PATCH] [RFC PATCH v2]mm/slub: Optimize slub memory usage

From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
To: Oliver Sang <oliver.sang@intel.com>
Cc: Jay Patel <jaypatel@linux.ibm.com>,
	oe-lkp@lists.linux.dev, lkp@intel.com,  linux-mm@kvack.org,
	ying.huang@intel.com, feng.tang@intel.com,
	 fengwei.yin@intel.com, cl@linux.com, penberg@kernel.org,
	rientjes@google.com,  iamjoonsoo.kim@lge.com,
	akpm@linux-foundation.org, vbabka@suse.cz,
	 aneesh.kumar@linux.ibm.com, tsahu@linux.ibm.com,
	piyushs@linux.ibm.com
Subject: Re: [PATCH] [RFC PATCH v2]mm/slub: Optimize slub memory usage
Date: Thu, 20 Jul 2023 23:15:04 +0900	[thread overview]
Message-ID: <CAB=+i9SRCZ1OKBTrojbnbR2YgtmGoRiuTW4VBqvbW1=TNgVWMQ@mail.gmail.com> (raw)
In-Reply-To: <CAB=+i9Rn0WXgK-CfaKy0k7HXHx3VEmSjzopaPakcThSG5Ri3vA@mail.gmail.com>

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On Thu, Jul 20, 2023 at 10:46 PM Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:
>
> On Thu, Jul 20, 2023 at 9:59 PM Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:
> > On Thu, Jul 20, 2023 at 12:01 PM Oliver Sang <oliver.sang@intel.com> 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)?

Oh, my mistake. It has nothing to do with reclamation modifiers.
The correct patch should be this. Sorry for the noise.

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From 74142b5131e731f662740d34623d93fd324f9b65 Mon Sep 17 00:00:00 2001
From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
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@gmail.com>
---
 mm/slub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/slub.c b/mm/slub.c
index f7940048138c..c584237d6a0d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2010,7 +2010,7 @@ static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 	 * Let the initial higher-order allocation fail under memory pressure
 	 * so we fall-back to the minimum order allocation.
 	 */
-	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
+	alloc_gfp = (flags | __GFP_THISNODE | __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;
 
-- 
2.41.0

