From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C1F0C433F5 for ; Fri, 26 Nov 2021 10:49:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7499A6B0072; Fri, 26 Nov 2021 05:48:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6F9566B0078; Fri, 26 Nov 2021 05:48:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E8F16B007B; Fri, 26 Nov 2021 05:48:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0094.hostedemail.com [216.40.44.94]) by kanga.kvack.org (Postfix) with ESMTP id 513BB6B0072 for ; Fri, 26 Nov 2021 05:48:59 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 1A2DB824C42C for ; Fri, 26 Nov 2021 10:48:49 +0000 (UTC) X-FDA: 78850758378.16.B60F95B Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf16.hostedemail.com (Postfix) with ESMTP id 3A392F00008C for ; Fri, 26 Nov 2021 10:48:44 +0000 (UTC) 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> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 3A392F00008C X-Stat-Signature: gnfbms4rkbdz4nwo3tfc4b1f7os7p9jy Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=cYhFEEY3; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf16.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com X-HE-Tag: 1637923724-694487 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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