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 BC4BB80034; Mon, 26 Aug 2024 19:41:47 +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=1724701309; cv=none; b=VR/hGsnr8X3EsEpvtoe1sIqDODAULDxlHHg+uYtK1R0soea2AvYX1JAn+4uQWy1Uos8OgwWdho2/piPy3BK18BPYagYkrTow0f3G5ZFHZi6gsXBJeG4WrIsjmPetx4gnnPANNeRR+q6hjov/aqr0Rk1mDkkBZliPuhIfayelwP0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724701309; c=relaxed/simple; bh=rQg+bs4LSYTBr14ItbIkLw2k8hVj9LRq9zs7I9326GI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=esgKde4vKKBrTStcjkJOUkU8jTx8Z5pHzqpwX/YAYuPQbE5nRy3qOtSYMt7NzHOQUz/Z3VPskiJSCuOXh257zyfLFSf/bTiw0+1fz4YMOHIJjDEUyG/WkRgvuVL6iHXjhDSHjJxnKLby3urpMunw8RInQe/gmw9bGNp4LqrbVtU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (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=oThpUoU5; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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="oThpUoU5" 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=4GhdGhSKm/X6M79tv+fW2tzMUeqm3WW+Lfyk9i49dck=; b=oThpUoU5vYTVKD5qeQ01khcag6 iKPwDcC1WirdPD97QM6WSkOuTlTTSE1wD+paQpI9tCvtzZhoy9453c5qgEt0deqKYTeTGey7YfUwq SG/I4AAetAEiE/WRrar65awouCdeW8kThmqOknroHf/zviskvBnfbzaMZeo/iZJvlaqS4d2X1iGvO Wu/Rr4XjNT2MRrsyQ3FJP6PMvdoOftPdvgA1Kp2ZLcM9qYV9JahuHKrdhVogufDU6UdmF6uVg3dmS tc4e+I5AWpqnNMznPbJ8qI+N9sCl9gk4/heib5YctZCBpEEQRUArbfbIWQen6SEgDq3RKWODqoyyE 0J85j6DA==; Received: from willy by casper.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1sifaw-0000000FvjY-0toK; Mon, 26 Aug 2024 19:41:42 +0000 Date: Mon, 26 Aug 2024 20:41:42 +0100 From: Matthew Wilcox To: Kent Overstreet Cc: Michal Hocko , Andrew Morton , Christoph Hellwig , Yafang Shao , jack@suse.cz, Christian Brauner , Alexander Viro , Paul Moore , James Morris , "Serge E. Hallyn" , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-bcachefs@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Hocko Subject: Re: [PATCH 1/2] bcachefs: do not use PF_MEMALLOC_NORECLAIM Message-ID: References: <20240826085347.1152675-1-mhocko@kernel.org> <20240826085347.1152675-2-mhocko@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@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 Mon, Aug 26, 2024 at 03:39:47PM -0400, Kent Overstreet wrote: > Given the amount of plumbing required here, it's clear that passing gfp > flags is the less safe way of doing it, and this really does belong in > the allocation context. > > Failure to pass gfp flags correctly (which we know is something that > happens today, e.g. vmalloc -> pte allocation) means you're introducing > a deadlock. The problem with vmalloc is that the page table allocation _doesn't_ take a GFP parameter.