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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33DA0C433F5 for ; Fri, 26 Nov 2021 15:34:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378123AbhKZPhr (ORCPT ); Fri, 26 Nov 2021 10:37:47 -0500 Received: from smtp-out1.suse.de ([195.135.220.28]:44450 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354667AbhKZPfk (ORCPT ); Fri, 26 Nov 2021 10:35:40 -0500 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id DEE362191A; Fri, 26 Nov 2021 15:32:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1637940746; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4OPGGG/iKy2NLyQ5ovfbpVS9DeN3FCw/U9mCaWyfW0Y=; b=awh5HL8S8Ggxp5+RF2rsxFt+zZepTctjNHS7/tsWg+xjm9qpg3VAcaPxkfT8v3zQ1d/LGn Jw/ByaZJ+0mB0/zCPT5CstBZtcwhXKaMTbpYMXcswlc/prbA08ix3sqnjc+crHYXvUlHzD yIBHOQu6TLnkT/vObhVpF0hFV8bUHL8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1637940746; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4OPGGG/iKy2NLyQ5ovfbpVS9DeN3FCw/U9mCaWyfW0Y=; b=ADwz39vvqUlJq5Ls4//kyWbe1lO+hcj+6R+kSIAxk3CrEHCUPrH1jhrDHqOOPQLMKP7Mal StfEUYeBIBfaQEDg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id ACDA513C65; Fri, 26 Nov 2021 15:32:26 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 6nlfKQr+oGHfbgAAMHmgww (envelope-from ); Fri, 26 Nov 2021 15:32:26 +0000 Message-ID: Date: Fri, 26 Nov 2021 16:32:26 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Subject: Re: [PATCH v2 2/4] mm/vmalloc: add support for __GFP_NOFAIL Content-Language: en-US To: Michal Hocko , 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 , Michal Hocko References: <20211122153233.9924-1-mhocko@kernel.org> <20211122153233.9924-3-mhocko@kernel.org> From: Vlastimil Babka In-Reply-To: <20211122153233.9924-3-mhocko@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/22/21 16:32, 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 Acked-by: Vlastimil Babka > @@ -2921,6 +2923,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > { > const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO; > const gfp_t orig_gfp_mask = gfp_mask; > + bool nofail = gfp_mask & __GFP_NOFAIL; > unsigned long addr = (unsigned long)area->addr; > unsigned long size = get_vm_area_size(area); > unsigned long array_size; > @@ -2978,8 +2981,12 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0) > flags = memalloc_noio_save(); > > - ret = vmap_pages_range(addr, addr + size, prot, area->pages, > + do { > + ret = vmap_pages_range(addr, addr + size, prot, area->pages, > page_shift); > + if (nofail && (ret < 0)) > + schedule_timeout_uninterruptible(1); > + } while (nofail && (ret < 0)); Kind of ugly to have the same condition twice here, but no hard feelings. > > if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO) > memalloc_nofs_restore(flags); > @@ -3074,9 +3081,14 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, > VM_UNINITIALIZED | vm_flags, start, end, node, > gfp_mask, caller); > if (!area) { > + bool nofail = gfp_mask & __GFP_NOFAIL; > warn_alloc(gfp_mask, NULL, > - "vmalloc error: size %lu, vm_struct allocation failed", > - real_size); > + "vmalloc error: size %lu, vm_struct allocation failed%s", > + real_size, (nofail) ? ". Retrying." : ""); > + if (nofail) { > + schedule_timeout_uninterruptible(1); > + goto again; > + } > goto fail; > } > >