From patchwork Wed Aug 23 13:13:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandru Elisei X-Patchwork-Id: 13362317 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 905DBEE49A3 for ; Wed, 23 Aug 2023 13:15:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235574AbjHWNPS (ORCPT ); Wed, 23 Aug 2023 09:15:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235564AbjHWNPR (ORCPT ); Wed, 23 Aug 2023 09:15:17 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 8C2D9171C; Wed, 23 Aug 2023 06:14:53 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B6AC91595; Wed, 23 Aug 2023 06:15:33 -0700 (PDT) Received: from e121798.cable.virginm.net (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 51AF33F740; Wed, 23 Aug 2023 06:14:47 -0700 (PDT) From: Alexandru Elisei To: catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, arnd@arndb.de, akpm@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, mhiramat@kernel.org, rppt@kernel.org, hughd@google.com Cc: pcc@google.com, steven.price@arm.com, anshuman.khandual@arm.com, vincenzo.frascino@arm.com, david@redhat.com, eugenis@google.com, kcc@google.com, hyesoo.yu@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH RFC 07/37] mm: page_alloc: Bypass pcp when freeing MIGRATE_METADATA pages Date: Wed, 23 Aug 2023 14:13:20 +0100 Message-Id: <20230823131350.114942-8-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230823131350.114942-1-alexandru.elisei@arm.com> References: <20230823131350.114942-1-alexandru.elisei@arm.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org When a metadata page is returned to the page allocator because all the associated pages with metadata were freed, the page will be returned to the pcp list, which makes it very likely that it will be used to satisfy an allocation request. This is not optimal, because metadata pages should be used as a last resort, to increase the chances they are not in use when they are needed, to avoid costly page migration. Bypass the pcp lists when freeing metadata pages. Note that metadata pages can still end up on the pcp lists when a list is refilled, but this should only happen when memory is running low, which is as intended Signed-off-by: Alexandru Elisei --- mm/page_alloc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a693e23c4733..bbb49b489230 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2478,7 +2478,8 @@ void free_unref_page(struct page *page, unsigned int order) */ migratetype = get_pcppage_migratetype(page); if (unlikely(migratetype >= MIGRATE_PCPTYPES)) { - if (unlikely(is_migrate_isolate(migratetype))) { + if (unlikely(is_migrate_isolate(migratetype) || + is_migrate_metadata(migratetype))) { free_one_page(page_zone(page), page, pfn, order, migratetype, FPI_NONE); return; } @@ -2522,7 +2523,8 @@ void free_unref_page_list(struct list_head *list) * comment in free_unref_page. */ migratetype = get_pcppage_migratetype(page); - if (unlikely(is_migrate_isolate(migratetype))) { + if (unlikely(is_migrate_isolate(migratetype) || + is_migrate_metadata(migratetype))) { list_del(&page->lru); free_one_page(page_zone(page), page, pfn, 0, migratetype, FPI_NONE); continue;