Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C1E1C433F5 for ; Fri, 26 Nov 2021 10:50:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238038AbhKZKyD (ORCPT ); Fri, 26 Nov 2021 05:54:03 -0500 Received: from smtp-out1.suse.de ([195.135.220.28]:33320 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376824AbhKZKwB (ORCPT ); Fri, 26 Nov 2021 05:52:01 -0500 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 672512191E; Fri, 26 Nov 2021 10:48:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1637923727; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=z4wlzPXcHY1E4jnsxIlOVyE4bXQ2QOsHbiS5pKe8Jrg=; b=cYhFEEY32kdRfruql7qB2OOrS2FuoDklEOM0w0eV1ukDmK1Jf3qiEUQjrZsuLFljg8RgR2 mslbGlMji8p7NPqa/LEHaecjc2iTYmLUxOqZQMSGcyuStdBF23ZOZaCDUZ1R7SUd4Fk7eI Lye9iW1ZJ/X+9f0lBzP3/1ExedN5fWI= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 5000FA3B81; Fri, 26 Nov 2021 10:48:47 +0000 (UTC) Date: Fri, 26 Nov 2021 11:48:46 +0100 From: Michal Hocko To: Andrew Morton Cc: Dave Chinner , Neil Brown , Christoph Hellwig , Uladzislau Rezki , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, LKML , Ilya Dryomov , Jeff Layton Subject: Re: [PATCH v2 2/4] mm/vmalloc: add support for __GFP_NOFAIL Message-ID: References: <20211122153233.9924-1-mhocko@kernel.org> <20211122153233.9924-3-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211122153233.9924-3-mhocko@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 22-11-21 16:32:31, Michal Hocko wrote: > From: Michal Hocko > > Dave Chinner has mentioned that some of the xfs code would benefit from > kvmalloc support for __GFP_NOFAIL because they have allocations that > cannot fail and they do not fit into a single page. > > The large part of the vmalloc implementation already complies with the > given gfp flags so there is no work for those to be done. The area > and page table allocations are an exception to that. Implement a retry > loop for those. > > Add a short sleep before retrying. 1 jiffy is a completely random > timeout. Ideally the retry would wait for an explicit event - e.g. > a change to the vmalloc space change if the failure was caused by > the space fragmentation or depletion. But there are multiple different > reasons to retry and this could become much more complex. Keep the retry > simple for now and just sleep to prevent from hogging CPUs. > > Signed-off-by: Michal Hocko Are there still any concerns around this patch or the approach in general? -- Michal Hocko SUSE Labs