From: Hugh Dickins <hughd@google.com>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: Hugh Dickins <hughd@google.com>,
akpm@linux-foundation.org, willy@infradead.org,
brauner@kernel.org, linux-mm@kvack.org, p.raghav@samsung.com,
da.gomez@samsung.com, a.manzanares@samsung.com,
dave@stgolabs.net, yosryahmed@google.com, keescook@chromium.org,
patches@lists.linux.dev, linux-kernel@vger.kernel.org,
David Hildenbrand <david@redhat.com>
Subject: Re: [PATCH v2 4/6] shmem: skip page split if we're not reclaiming
Date: Tue, 18 Apr 2023 14:20:55 -0700 (PDT) [thread overview]
Message-ID: <8afe1f7f-31a2-4fc0-1fbd-f9ba8a116fe3@google.com> (raw)
In-Reply-To: <ZD8HdxbwhUUGvmNC@bombadil.infradead.org>
On Tue, 18 Apr 2023, Luis Chamberlain wrote:
> On Mon, Apr 17, 2023 at 09:41:41PM -0700, Hugh Dickins wrote:
> > On Thu, 9 Mar 2023, Luis Chamberlain wrote:
> >
> > > + if (WARN_ON_ONCE(info->flags & VM_LOCKED))
> > > + goto redirty;
> >
> > Well, okay, I don't mind that. But shall we take bets on how soon syzbot
> > (hope it's not watching) will try flipping SHM_LOCK on while swapping out
> > pages from a SHM segment, and hit that warning? Perhaps I'm wrong, but I
> > don't think any serialization prevents that.
>
> I though that may be the case. Would such serialization be welcomed?
Absolutely not! We don't insert slowdowns just to avoid warnings,
unless the warning is of something that really matters. This one
does not matter, the situation is correctly handled, so the warning
would be better reverted. Though I personally don't mind you leaving
it in until the first report of it arrives.
Hugh
next prev parent reply other threads:[~2023-04-18 21:21 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-09 23:05 [PATCH v2 0/6] tmpfs: add the option to disable swap Luis Chamberlain
2023-03-09 23:05 ` [PATCH v2 1/6] shmem: remove check for folio lock on writepage() Luis Chamberlain
2023-03-09 23:05 ` [PATCH v2 2/6] shmem: set shmem_writepage() variables early Luis Chamberlain
2023-03-09 23:05 ` [PATCH v2 3/6] shmem: move reclaim check early on writepages() Luis Chamberlain
2023-03-09 23:05 ` [PATCH v2 4/6] shmem: skip page split if we're not reclaiming Luis Chamberlain
2023-03-09 23:09 ` Yosry Ahmed
2023-04-18 4:41 ` Hugh Dickins
2023-04-18 21:11 ` Luis Chamberlain
2023-04-18 21:20 ` Hugh Dickins [this message]
2023-03-09 23:05 ` [PATCH v2 5/6] shmem: update documentation Luis Chamberlain
2023-04-18 5:29 ` Hugh Dickins
2023-04-18 21:20 ` Luis Chamberlain
2023-04-18 21:41 ` Hugh Dickins
2023-04-18 21:49 ` Luis Chamberlain
2023-03-09 23:05 ` [PATCH v2 6/6] shmem: add support to ignore swap Luis Chamberlain
2023-04-18 5:50 ` Hugh Dickins
2023-04-18 7:38 ` Christian Brauner
2023-04-18 21:51 ` Luis Chamberlain
2023-04-20 8:57 ` [PATCH] shmem: restrict noswap option to initial user namespace Christian Brauner
2023-04-20 19:18 ` Luis Chamberlain
2023-04-18 21:22 ` [PATCH v2 6/6] shmem: add support to ignore swap Luis Chamberlain
2023-04-18 21:30 ` Randy Dunlap
2023-03-14 1:21 ` [PATCH v2 0/6] tmpfs: add the option to disable swap Davidlohr Bueso
2023-03-14 2:46 ` haoxin
2023-03-19 20:32 ` Luis Chamberlain
[not found] ` <edb78eea-a9a2-5c62-d203-6f2be39757d2@linux.alibaba.com>
2023-03-20 21:36 ` Luis Chamberlain
2023-03-21 11:37 ` haoxin
2023-04-18 4:31 ` Hugh Dickins
2023-04-18 20:55 ` Luis Chamberlain
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