From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A76A346FBC for ; Tue, 16 Dec 2025 15:35:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765899320; cv=none; b=KFodUvxtIwuy1CaD2hi34BonFQkdBZVS7RmzLrnihn1Vsof/bji+7qWP06Bd5pSj//ZYpdfZuOzBZvDfIwceeUKAAbhjiWCkgNcQCOanIMXHnFMHjmY7HF+IHijXR2lk1Tr0R4LY6M/LUpVOW5GoHEscb/udw/Wgd6wCon/MQjU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765899320; c=relaxed/simple; bh=DHe4++e3jEAJ48ZTdDEajsDxmY2dv864JsvPNJoCVSY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DzRWU6c1oojWqx6Wthtttr9tm47CNv1qsetaPGJlGPRgZvje72IZgQeAztWvrAUnFfB6obHsVnLMtk5c3MG9femklYyHxIMyH4n2kXDWNICo+V8s+u5crkhK69JwwYwao09oJlxdppD8otapeY3oHEYBFxMz0gjyKVfwKyNaEbk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RwDbeAtL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RwDbeAtL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F857C4CEF1; Tue, 16 Dec 2025 15:35:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765899319; bh=DHe4++e3jEAJ48ZTdDEajsDxmY2dv864JsvPNJoCVSY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RwDbeAtL9wfRchcz4X6YkqGg9vw8vQY8I+6rTGf3FIXou7JxOzQIpyWB1voF/UbLV Q9kAVhPKFz7qgJL4h7IbJrZN1/Aq69hDMBEp5nVnOp1FrIx/to+BiUTWbOEvyMESy1 sQIip9VPDbMvDtr2BkElPu/9H8L3dZHQS1wiPg3lS31kzTFV+HizebZFhjE+zEge9X /kgbxalzWoKgAocYtfEbRKX+ZPAP0Urj4DEbAKapC5ufTA/Wwidlifavh+eeXVcfXm KYpkp+MHjrXTWV8gFLXgNwC4l+bF4MC682AJEmUVU6KhhUo9x0w4am5KDG4WYKJK3E g1W5QxmhzGKpg== Date: Tue, 16 Dec 2025 08:35:17 -0700 From: Tycho Andersen To: Oleg Nesterov Cc: Christian Brauner , linux-kernel@vger.kernel.org Subject: Re: [PATCH] pid: remove unnecessary idr_preload() Message-ID: References: <20251215201514.1343231-1-tycho@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Dec 16, 2025 at 10:39:58AM +0100, Oleg Nesterov wrote: > On 12/15, Tycho Andersen wrote: > > > > From: "Tycho Andersen (AMD)" > > > > 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