From: Gregory Price <gourry@gourry.net>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
edumazet@google.com, linux-kernel@vger.kernel.org,
kernel-team@meta.com, stable@vger.kernel.org, david@kernel.org,
ziy@nvidia.com, matthew.brost@intel.com,
joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com,
ying.huang@linux.alibaba.com, apopple@nvidia.com,
syzbot+0dbf6d295b3350944f0b@syzkaller.appspotmail.com
Subject: Re: [PATCH] mm/mempolicy: refcount the weighted interleave state instead of copying it
Date: Sun, 23 Aug 2026 23:52:55 -0400 [thread overview]
Message-ID: <aou9WUf2qU8UewL7@gourry-fedora-PF4VCD3F> (raw)
In-Reply-To: <aou1Gwxk2s8Qjdm9@casper.infradead.org>
On Mon, Aug 24, 2026 at 04:06:03AM +0100, Matthew Wilcox wrote:
> On Sun, Aug 23, 2026 at 10:41:17PM -0400, Gregory Price wrote:
>
> Bit of a shame to take/put a refcount on every memory allocation. That
> seems like it might hurt (even being on a different cacheline). Would
> it make more sense to use SRCU for this?
Bulk allocation - from some measurements it's about once per 100-pages
on average. Looking back at the data I was getting about 41 refs per
4096 pages (16MB chunks).
Have to imagine there's other cache fighting in that stack too.
I'm less familiar with the rules around SRCU so i shied away from it,
but I will take a look.
~Gregory
next prev parent reply other threads:[~2026-08-24 3:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-21 17:04 [PATCH] mm/mempolicy: Fix sleeping allocation in alloc_pages_bulk_weighted_interleave() Eric Dumazet
2026-08-21 17:40 ` Gregory Price
2026-08-21 17:40 ` Andrew Morton
2026-08-21 17:47 ` Gregory Price
2026-08-21 17:59 ` Eric Dumazet
2026-08-23 23:01 ` Gregory Price
2026-08-24 2:41 ` [PATCH] mm/mempolicy: refcount the weighted interleave state instead of copying it Gregory Price
2026-08-24 3:06 ` Matthew Wilcox
2026-08-24 3:52 ` Gregory Price [this message]
2026-08-24 15:09 ` Gregory Price
2026-08-24 18:39 ` Andrew Morton
2026-08-24 10:12 ` [PATCH] mm/mempolicy: Fix sleeping allocation in alloc_pages_bulk_weighted_interleave() David Hildenbrand (Arm)
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