From: Tycho Andersen <tycho@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Christian Brauner <brauner@kernel.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] pid: remove unnecessary idr_preload()
Date: Tue, 16 Dec 2025 08:35:17 -0700 [thread overview]
Message-ID: <aUF8NT5_i6y85-zc@tycho.pizza> (raw)
In-Reply-To: <aUEo7kY306q-yC-i@redhat.com>
On Tue, Dec 16, 2025 at 10:39:58AM +0100, Oleg Nesterov wrote:
> On 12/15, Tycho Andersen wrote:
> >
> > From: "Tycho Andersen (AMD)" <tycho@kernel.org>
> >
> > As near as I can tell, nothing in the second pidmap_lock critical section
> > actually allocates an id, so there is no need to do idr_preload().
> > idr_replace() does not, nor does pidfs_add_pid().
>
> Yes. The extra idr_preload() was needed for pidfs_add_pid() after the commit
> 9698d5a483654 ("pidfs: rework inode number allocation").
>
> But please see
> [PATCH v3 2/2] pid: only take pidmap_lock once on alloc
> https://lore.kernel.org/all/20251206131955.780557-3-mjguzik@gmail.com/
Oh, nice. I was looking at doing this too. I'll head over to that
thread...
Tycho
next prev parent reply other threads:[~2025-12-16 15:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-15 20:15 [PATCH] pid: remove unnecessary idr_preload() Tycho Andersen
2025-12-16 9:39 ` Oleg Nesterov
2025-12-16 15:35 ` Tycho Andersen [this message]
2025-12-16 9:44 ` Oleg Nesterov
2025-12-16 10:02 ` Mateusz Guzik
2025-12-16 15:36 ` Tycho Andersen
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