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[82.17.115.212]) by smtp.gmail.com with ESMTPSA id k11sm6021496wmj.1.2021.05.19.07.50.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 May 2021 07:50:15 -0700 (PDT) From: Aaron Tomlin To: linux-mm@kvack.org Cc: akpm@linux-foundation.org, vbabka@suse.cz, mhocko@suse.com, linux-kernel@vger.kernel.org Subject: [PATCH] mm/page_alloc: bail out on fatal signal during reclaim/compaction retry attempt Date: Wed, 19 May 2021 15:50:14 +0100 Message-Id: <20210519145014.3220164-1-atomlin@redhat.com> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20210519130609.r3ml6ohb2qsrfq2t@ava.usersys.com> References: <20210519130609.r3ml6ohb2qsrfq2t@ava.usersys.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It does not make sense to retry compaction when the last known compact result was skipped and a fatal signal is pending. In the context of try_to_compact_pages(), indeed COMPACT_SKIPPED can be returned; albeit, not every zone, on the zone list, would be considered in the case a fatal signal is found to be pending. Yet, in should_compact_retry(), given the last known compaction result, each zone, on the zone list, can be considered/or checked (see compaction_zonelist_suitable()). For example, if a zone was found to succeed, then reclaim/compaction would be tried again (notwithstanding the above). This patch ensures that compaction is not needlessly retried when the last known compaction result was skipped and in the unlikely case a fatal signal is found pending. So, OOM is at least attempted. Signed-off-by: Aaron Tomlin --- mm/page_alloc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index aaa1655cf682..5f9aac27a1b5 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4268,6 +4268,8 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, * to work with, so we retry only if it looks like reclaim can help. */ if (compaction_needs_reclaim(compact_result)) { + if (fatal_signal_pending(current)) + goto out; ret = compaction_zonelist_suitable(ac, order, alloc_flags); goto out; } -- 2.26.3