From patchwork Tue Sep 14 00:13:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 12491091 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48C8CC433F5 for ; Tue, 14 Sep 2021 00:28:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27B5761212 for ; Tue, 14 Sep 2021 00:28:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238708AbhINAaB (ORCPT ); Mon, 13 Sep 2021 20:30:01 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:47790 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238446AbhINA37 (ORCPT ); Mon, 13 Sep 2021 20:29:59 -0400 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 230D921E66; Tue, 14 Sep 2021 00:28:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1631579321; 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=kKg7RlKucOqg4kFvULlcfcgLDUa14h212dG0lQnULcE=; b=awMekhqm0ZNbe0UAJauJmcBwIc7nmh/WiO0Wm1svGCnQLjolPKb5AEyzgL6E7o+LIz4y5b lmX317K+JkPpTEpTlv/8PeWzfPTcsJIfAIpsVotoHrncS7969LnN3tar3wZGiAWm97fph1 H5B/qIkNeKC7yoT4eFeE3/rSAVYmUos= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1631579321; 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=kKg7RlKucOqg4kFvULlcfcgLDUa14h212dG0lQnULcE=; b=2y/BbnOYFFsEbgxZG3DjeobRaJHXJPGcoflnoSvt9f/Hntganr1MCbrR5BikDTWxDcsICr wEc7foc1STYeTIBA== 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 86E1A13ADE; Tue, 14 Sep 2021 00:28:36 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id kqaiEbTsP2FYawAAMHmgww (envelope-from ); Tue, 14 Sep 2021 00:28:36 +0000 From: NeilBrown To: Andrew Morton , Theodore Ts'o , Andreas Dilger , "Darrick J. Wong" , Matthew Wilcox , Mel Gorman Date: Tue, 14 Sep 2021 10:13:04 +1000 Subject: [PATCH 6/6] XFS: remove congestion_wait() loop from xfs_buf_alloc_pages() Cc: linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Message-ID: <163157838440.13293.12568710689057349786.stgit@noble.brown> In-Reply-To: <163157808321.13293.486682642188075090.stgit@noble.brown> References: <163157808321.13293.486682642188075090.stgit@noble.brown> User-Agent: StGit/0.23 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Documentation commment in gfp.h discourages indefinite retry loops on ENOMEM and says of __GFP_NOFAIL that it is definitely preferable to use the flag rather than opencode endless loop around allocator. congestion_wait() is indistinguishable from schedule_timeout_uninterruptible() in practice and it is not a good way to wait for memory to become available. So instead of waiting, allocate a single page using __GFP_NOFAIL, then loop around and try to get any more pages that might be needed with a bulk allocation. This single-page allocation will wait in the most appropriate way. Signed-off-by: NeilBrown --- fs/xfs/xfs_buf.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 5fa6cd947dd4..1ae3768f6504 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -372,8 +372,8 @@ xfs_buf_alloc_pages( /* * Bulk filling of pages can take multiple calls. Not filling the entire - * array is not an allocation failure, so don't back off if we get at - * least one extra page. + * array is not an allocation failure, so don't fail or fall back on + * __GFP_NOFAIL if we get at least one extra page. */ for (;;) { long last = filled; @@ -394,7 +394,7 @@ xfs_buf_alloc_pages( } XFS_STATS_INC(bp->b_mount, xb_page_retries); - congestion_wait(BLK_RW_ASYNC, HZ / 50); + bp->b_pages[filled++] = alloc_page(gfp_mask | __GFP_NOFAIL); } return 0; }