From: Gregory Price <gourry@gourry.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Dumazet <edumazet@google.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
syzbot+0dbf6d295b3350944f0b@syzkaller.appspotmail.com,
David Hildenbrand <david@kernel.org>, Zi Yan <ziy@nvidia.com>,
Matthew Brost <matthew.brost@intel.com>,
Joshua Hahn <joshua.hahnjy@gmail.com>,
Rakie Kim <rakie.kim@sk.com>, Byungchul Park <byungchul@sk.com>,
Ying Huang <ying.huang@linux.alibaba.com>,
Alistair Popple <apopple@nvidia.com>,
linux-mm@kvack.org
Subject: Re: [PATCH] mm/mempolicy: Fix sleeping allocation in alloc_pages_bulk_weighted_interleave()
Date: Fri, 21 Aug 2026 13:47:10 -0400 [thread overview]
Message-ID: <aoiONiqcPJG11J88@gourry-fedora-PF4VCD3F> (raw)
In-Reply-To: <20260821104043.f692421fec915c0c5bc1fbe6@linux-foundation.org>
On Fri, Aug 21, 2026 at 10:40:43AM -0700, Andrew Morton wrote:
> On Fri, 21 Aug 2026 17:04:07 +0000 Eric Dumazet <edumazet@google.com> wrote:
>
> I wonder if we *really* need the local copy of state->iw_table.
> Perhaps with appropriate care we can directly use state->iw_table in
> here.
>
> How much would it hurt to expand the rcu_read_lock() coverage?
>
> A local array of MAX_NUMNODES bytes isn't attractive - 1k of stack.
>
> A spinlock-protected static array would work, if super-rare slowpath.
>
I would need to go back through the original thread when i authored
this, but I think this is possible. I will add it to my backlog to
investigate.
Weight updates should be *extraordinarily* rare, unless someone is doing
dynamic runtime twiddling of the sysfs values and thinks that's somehow
a good idea (or expecting them to be timely).
~Gregory
next prev parent reply other threads:[~2026-08-21 17:47 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 [this message]
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
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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