From patchwork Mon Jun 8 13:28:44 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Hocko X-Patchwork-Id: 6565141 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 5B2829F3D1 for ; Mon, 8 Jun 2015 13:29:10 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7CCA220524 for ; Mon, 8 Jun 2015 13:29:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 797D82053A for ; Mon, 8 Jun 2015 13:29:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752208AbbFHN3G (ORCPT ); Mon, 8 Jun 2015 09:29:06 -0400 Received: from cantor2.suse.de ([195.135.220.15]:48716 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752022AbbFHN3E (ORCPT ); Mon, 8 Jun 2015 09:29:04 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id EE282ABB1; Mon, 8 Jun 2015 13:29:01 +0000 (UTC) From: Michal Hocko To: "Theodore Ts'o" Cc: linux-ext4@vger.kernel.org, David Rientjes , , , LKML Subject: [PATCH -resend] jbd2: revert must-not-fail allocation loops back to GFP_NOFAIL Date: Mon, 8 Jun 2015 15:28:44 +0200 Message-Id: <1433770124-19614-1-git-send-email-mhocko@suse.cz> X-Mailer: git-send-email 2.1.4 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This basically reverts 47def82672b3 (jbd2: Remove __GFP_NOFAIL from jbd2 layer). The deprecation of __GFP_NOFAIL was a bad choice because it led to open coding the endless loop around the allocator rather than removing the dependency on the non failing allocation. So the deprecation was a clear failure and the reality tells us that __GFP_NOFAIL is not even close to go away. It is still true that __GFP_NOFAIL allocations are generally discouraged and new uses should be evaluated and an alternative (pre-allocations or reservations) should be considered but it doesn't make any sense to lie the allocator about the requirements. Allocator can take steps to help making a progress if it knows the requirements. Signed-off-by: Michal Hocko Acked-by: David Rientjes --- Hi, this has been posted few months ago (http://marc.info/?l=linux-mm&m=142530454419654&w=2) but it hasn't gone anywhere so I am reposting. I've just rebased it on top of the ext4/for-linus tree. It wasn't clear to me which branch should I use so I've just picked this one as it was one of the most recently updated. fs/jbd2/journal.c | 11 +---------- fs/jbd2/transaction.c | 20 +++++++------------- 2 files changed, 8 insertions(+), 23 deletions(-) diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index b96bd8076b70..0bc333b4a594 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -371,16 +371,7 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction, */ J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in)); -retry_alloc: - new_bh = alloc_buffer_head(GFP_NOFS); - if (!new_bh) { - /* - * Failure is not an option, but __GFP_NOFAIL is going - * away; so we retry ourselves here. - */ - congestion_wait(BLK_RW_ASYNC, HZ/50); - goto retry_alloc; - } + new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL); /* keep subsequent assertions sane */ atomic_set(&new_bh->b_count, 1); diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index ff2f2e6ad311..799242cecffb 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -278,22 +278,16 @@ static int start_this_handle(journal_t *journal, handle_t *handle, alloc_transaction: if (!journal->j_running_transaction) { + /* + * If __GFP_FS is not present, then we may be being called from + * inside the fs writeback layer, so we MUST NOT fail. + */ + if ((gfp_mask & __GFP_FS) == 0) + gfp_mask |= __GFP_NOFAIL; new_transaction = kmem_cache_zalloc(transaction_cache, gfp_mask); - if (!new_transaction) { - /* - * If __GFP_FS is not present, then we may be - * being called from inside the fs writeback - * layer, so we MUST NOT fail. Since - * __GFP_NOFAIL is going away, we will arrange - * to retry the allocation ourselves. - */ - if ((gfp_mask & __GFP_FS) == 0) { - congestion_wait(BLK_RW_ASYNC, HZ/50); - goto alloc_transaction; - } + if (!new_transaction) return -ENOMEM; - } } jbd_debug(3, "New handle %p going live.\n", handle);