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 5958640BE0 for ; Fri, 1 Mar 2024 02:49:02 +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=1709261347; cv=none; b=QHd4ceRjb8MUNPBxftJy3givaYhvYJiBYjFg7aJiT7bcbblplOywiK3OKhf4npU6NL4IuVvxrgtCQxLV6H4I+cnSKueKtW6WyYqmm+LHVL4OdouvYMgdbdRkWCZe5C4vrBzdfv/PAJKosEegUnrnwzQ9zgPhpGaTZBO2vC0sQcA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709261347; c=relaxed/simple; bh=AjvcAEAjMzfUz8OjT5t7Y+LgCa352AKbVmGmmiMfqNQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=H2zvofe2Dw1zUbq8U6YU96W4DynOmG72KuSt6JwY5P8JorttOwWLB6aL0yVBuTROGhpzuyg/olra1LFcPd4FMgUtbk6XTjiOUM4/rsCIVFJlqPJiMAFcV2a4ZrYFANhMMnPORFbNJ9wwGxIP6jXdfb6lJJPyz8BV/jlytWiY+64= 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=APX3wsoE; 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="APX3wsoE" 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=6b1p1CdxXqPV7bP/CjdoesvhrJHckhGwDXs2VSS+vDA=; b=APX3wsoEeg4QYO0/GObrtgup+E HMFJCf/5HamxqqI4Ih5pRmfTnBsv0TBs0JH20L2dtED2V1AZTsLu8U9RgdCvU17Pg0w43IAVCEnG8 D5aNvyHYAYNNHWzxXegDJnThYpAgovn8yrrV5mMXTx/iPSldHhrwIuMDbTP2ARAux+MhxHdfozaBg +XDa5PPH7o54uok9b4Vt6Jtlw7+kM4EKvdkD/l38iOsvt1D8+WD4ZPwsMDK2sbe1VyxsmRW6KgfGM Bq/bVt0pIGjjDEntiqXUAwoqFV07pBoSimwca18fvssiI+lKaVMlVAhOcLeRCWZPrCZb/Y8Ak6ton v49SZGbg==; Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rfsxA-00000009hNq-3THo; Fri, 01 Mar 2024 02:48:52 +0000 Date: Fri, 1 Mar 2024 02:48:52 +0000 From: Matthew Wilcox To: Kent Overstreet Cc: NeilBrown , Amir Goldstein , paulmck@kernel.org, lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-fsdevel , Jan Kara Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Reclamation interactions with RCU Message-ID: References: <170925937840.24797.2167230750547152404@noble.neil.brown.name> 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 Thu, Feb 29, 2024 at 09:39:17PM -0500, Kent Overstreet wrote: > On Fri, Mar 01, 2024 at 01:16:18PM +1100, NeilBrown wrote: > > Insisting that GFP_KERNEL allocations never returned NULL would allow us > > to remove a lot of untested error handling code.... > > If memcg ever gets enabled for all kernel side allocations we might > start seeing failures of GFP_KERNEL allocations. Why would we want that behaviour? A memcg-limited allocation should behave like any other allocation -- block until we've freed some other memory in this cgroup, either by swap or killing or ...