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From: Peter Xu <peterx@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Jens Axboe <axboe@kernel.dk>,
	Andrew Morton <akpm@linux-foundation.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH] mm/userfaultfd: prevent busy looping for tasks with signals pending
Date: Thu, 24 Apr 2025 17:45:37 -0400	[thread overview]
Message-ID: <aAqxAX2PimC2uZds@x1.local> (raw)
In-Reply-To: <aAqUCK6V1I08cPpj@casper.infradead.org>

On Thu, Apr 24, 2025 at 08:42:00PM +0100, Matthew Wilcox wrote:
> On Thu, Apr 24, 2025 at 02:26:37PM -0400, Peter Xu wrote:
> > Secondly, userfaultfd is indeed the only consumer of
> > FAULT_FLAG_INTERRUPTIBLE but not necessary always in the future.  While
> > this patch resolves it for userfaultfd, it might get caught again later if
> > something else in the kernel starts to respects the _INTERRUPTIBLE flag
> > request.  For example, __folio_lock_or_retry() ignores that flag so far,
> > but logically it should obey too (with a folio_wait_locked_interruptible)..
> 
> No.  Hell, no.  We don't want non-fatal signals being able to interrupt
> that.  There's a reason we introduced killable as a concept in the first
> place.

Not really proposing that as I don't have a use caes.  Just curious, could
you explain a bit why having it interruptible is against the killable
concept if (IIUC) it is still killable?

Thanks,

-- 
Peter Xu


  reply	other threads:[~2025-04-24 21:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-23 23:37 [PATCH] mm/userfaultfd: prevent busy looping for tasks with signals pending Jens Axboe
2025-04-24 14:03 ` Johannes Weiner
2025-04-24 14:54   ` Jens Axboe
2025-04-24 15:11     ` Johannes Weiner
2025-04-24 15:22       ` Jens Axboe
2025-04-24 18:26   ` Peter Xu
2025-04-24 18:40     ` Jens Axboe
2025-04-24 19:13       ` Peter Xu
2025-04-24 19:20         ` Jens Axboe
2025-04-24 19:57           ` Peter Xu
2025-05-01 16:18             ` Peter Xu
2025-05-01 16:28               ` Peter Xu
2025-04-24 19:42     ` Matthew Wilcox
2025-04-24 21:45       ` Peter Xu [this message]
2025-04-25  4:52         ` Matthew Wilcox
2025-04-25 15:44           ` Peter Xu

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