From patchwork Thu Apr 28 15:42:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 567474 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 76CE8C433EF for ; Thu, 28 Apr 2022 15:43:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349516AbiD1Pq1 (ORCPT ); Thu, 28 Apr 2022 11:46:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349520AbiD1PqU (ORCPT ); Thu, 28 Apr 2022 11:46:20 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C9372B821A; Thu, 28 Apr 2022 08:43:02 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 19A5262010; Thu, 28 Apr 2022 15:43:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EAF52C385AE; Thu, 28 Apr 2022 15:43:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651160581; bh=uBhpMoiEbz/kzy6AX3rpsSw0CWwU7xwTlMeypxaO5Po=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GxkkCEAAWJoTphppzHibkcxUM81IURKMlKh3LYBQkIr+Mn7JeWIL+fLC08TLib+HZ LpQt9ptXPtjFwKApX6HukTOWXquSUqV0D0eeIeZjbfamW2wITFjq7c7HMGdyVYYdNh VzvPyu8kGK2CowpYFCOXtfvUY5cI32P2pEYfLQhY= From: Greg Kroah-Hartman To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Mel Gorman , Vlastimil Babka , Aaron Lu , Dave Hansen , Michal Hocko , Jesper Dangaard Brouer , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman Subject: [PATCH AUTOSEL 07/14] mm/page_alloc: fetch the correct pcp buddy during bulk free Date: Thu, 28 Apr 2022 17:42:15 +0200 Message-Id: <20220428154222.1230793-7-gregkh@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220428154222.1230793-1-gregkh@linuxfoundation.org> References: <20220428154222.1230793-1-gregkh@linuxfoundation.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3124; i=gregkh@linuxfoundation.org; h=from:subject; bh=tCOXBoUo5NxQepLUpCqvv6otafb9oNj1S1MmG8sm4mw=; b=owGbwMvMwCRo6H6F97bub03G02pJDElZW+8efZNz48WD91FnTyqYi+YEL07d4rHs3UYJaV+966H5 Bxde6YhlYRBkYpAVU2T5so3n6P6KQ4pehranYeawMoEMYeDiFICJpK5gmB/04G/zEu+3uUs9PzIJPS 1qfW3X/othnpriz49rzNUUXN+GcV88sNXiuaHaLwA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mel Gorman commit ca7b59b1de72450b3e696bada3506a519ac5455c upstream. Patch series "Follow-up on high-order PCP caching", v2. Commit 44042b449872 ("mm/page_alloc: allow high-order pages to be stored on the per-cpu lists") was primarily aimed at reducing the cost of SLUB cache refills of high-order pages in two ways. Firstly, zone lock acquisitions was reduced and secondly, there were fewer buddy list modifications. This is a follow-up series fixing some issues that became apparant after merging. Patch 1 is a functional fix. It's harmless but inefficient. Patches 2-5 reduce the overhead of bulk freeing of PCP pages. While the overhead is small, it's cumulative and noticable when truncating large files. The changelog for patch 4 includes results of a microbench that deletes large sparse files with data in page cache. Sparse files were used to eliminate filesystem overhead. Patch 6 addresses issues with high-order PCP pages being stored on PCP lists for too long. Pages freed on a CPU potentially may not be quickly reused and in some cases this can increase cache miss rates. Details are included in the changelog. This patch (of 6): free_pcppages_bulk() prefetches buddies about to be freed but the order must also be passed in as PCP lists store multiple orders. Link: https://lkml.kernel.org/r/20220217002227.5739-1-mgorman@techsingularity.net Link: https://lkml.kernel.org/r/20220217002227.5739-2-mgorman@techsingularity.net Fixes: 44042b449872 ("mm/page_alloc: allow high-order pages to be stored on the per-cpu lists") Signed-off-by: Mel Gorman Reviewed-by: Vlastimil Babka Reviewed-by: Aaron Lu Tested-by: Aaron Lu Cc: Dave Hansen Cc: Michal Hocko Cc: Jesper Dangaard Brouer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/page_alloc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e6f211dcf82e..b2ef0e75fd29 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1432,10 +1432,10 @@ static bool bulkfree_pcp_prepare(struct page *page) } #endif /* CONFIG_DEBUG_VM */ -static inline void prefetch_buddy(struct page *page) +static inline void prefetch_buddy(struct page *page, unsigned int order) { unsigned long pfn = page_to_pfn(page); - unsigned long buddy_pfn = __find_buddy_pfn(pfn, 0); + unsigned long buddy_pfn = __find_buddy_pfn(pfn, order); struct page *buddy = page + (buddy_pfn - pfn); prefetch(buddy); @@ -1512,7 +1512,7 @@ static void free_pcppages_bulk(struct zone *zone, int count, * prefetch buddy for the first pcp->batch nr of pages. */ if (prefetch_nr) { - prefetch_buddy(page); + prefetch_buddy(page, order); prefetch_nr--; } } while (count > 0 && --batch_free && !list_empty(list));