From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 814D023B61E for ; Sun, 7 Dec 2025 07:21:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765092075; cv=none; b=Y9fOh2vb/Zckw4wtCXYhNIwZRpGORi8vIiXV63dnbTPXWFpMnt4VlgtlGN/BBllDWMfewkXtnaLTqwNzmfPOFmbi0tITMKFc4OGKobvQ5J6BlYtgEudKbnJ01n+fU1njRTWVYKqR1ZRCZ9fe5hhgD0eiU3Wo1FzeBvQXEMcqHCk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765092075; c=relaxed/simple; bh=gFKP8YpAyRbBjNtZsvoPerHfaa7GupuIlZArUIsFj4o=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Cb1mEUWkWXBqrFdP0c2c7R6Pulxrwa/p+B1sQ6EPng1AKrf6j4LSAJuSUAChLMElxqfiezK/QshQzpLlZT8GNRuqJb9x4Q9UZF16puWUtnnypH7BPfMn3aSJxY1uPz8PQ2YCmiwSCM5Hgui6phDs8jWUZmq+uoEWBsNvcibQRoU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=sJZofoSr; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="sJZofoSr" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=tWoN0zrPs1ktRzfHfM53EvlXPHcMovoLY3RGcDQFkfI=; b=sJZofoSribCmp/scm0scD4WLrr p6mLCGcSnklc8oQVxqNrgQWabR6t/7yXbDm3Qk1eBvvUnYNaIDS6Q8v/ndRFJImYUJup0piyjDp6q 8cTT82MocP2FErjlO56hWOO7mpJr8lrCuYOx9rMYm+ZagYejAUIQs2FoCfc1wtyjiW7YNnFsxixHa aiUckb7TAvfCTW5I2kCRVsA8vvkT2mvjZptn4bF03tK+7TpmJK01xqgrUcWxq5uI6uKNJfUSfZIe6 fnaNzzo8vP4JWF8njpXDu7LGVG++Qnqdq3FAckQ8gZiQPSVaY4t60JTyh/JYMbrQ+uyUMlv6Etirq Cdm8xsPQ==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vS94v-00000008990-3uRg; Sun, 07 Dec 2025 07:21:10 +0000 Date: Sun, 7 Dec 2025 07:21:09 +0000 From: Matthew Wilcox To: Mateusz Guzik Cc: oleg@redhat.com, brauner@kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org Subject: Re: [PATCH v3 2/2] pid: only take pidmap_lock once on alloc Message-ID: References: <20251206131955.780557-1-mjguzik@gmail.com> <20251206131955.780557-3-mjguzik@gmail.com> 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: <20251206131955.780557-3-mjguzik@gmail.com> On Sat, Dec 06, 2025 at 02:19:55PM +0100, Mateusz Guzik wrote: > - if (!pid) > + if (unlikely(!pid)) Does this change anything? I was under the impression that gcc already treats !p as unlikely.