From nobody Thu Feb 12 03:20:14 2026 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 080A2C77B60 for ; Fri, 28 Apr 2023 11:01:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345523AbjD1LBq (ORCPT ); Fri, 28 Apr 2023 07:01:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229600AbjD1LBn (ORCPT ); Fri, 28 Apr 2023 07:01:43 -0400 Received: from SHSQR01.spreadtrum.com (unknown [222.66.158.135]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A88882706 for ; Fri, 28 Apr 2023 04:01:40 -0700 (PDT) Received: from SHSend.spreadtrum.com (bjmbx01.spreadtrum.com [10.0.64.7]) by SHSQR01.spreadtrum.com with ESMTP id 33SB17r7034907; Fri, 28 Apr 2023 19:01:07 +0800 (+08) (envelope-from zhaoyang.huang@unisoc.com) Received: from bj03382pcu.spreadtrum.com (10.0.74.65) by BJMBX01.spreadtrum.com (10.0.64.7) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Fri, 28 Apr 2023 19:01:01 +0800 From: "zhaoyang.huang" To: Andrew Morton , Roman Gushchin , Roman Gushchin , , , Zhaoyang Huang , Subject: [PATCH] mm: optimization on page allocation when CMA enabled Date: Fri, 28 Apr 2023 19:00:41 +0800 Message-ID: <1682679641-13652-1-git-send-email-zhaoyang.huang@unisoc.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 X-Originating-IP: [10.0.74.65] X-ClientProxiedBy: SHCAS01.spreadtrum.com (10.0.1.201) To BJMBX01.spreadtrum.com (10.0.64.7) X-MAIL: SHSQR01.spreadtrum.com 33SB17r7034907 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Zhaoyang Huang Please be notice bellowing typical scenario that commit 168676649 introduce, that is, 12MB free cma pages 'help' GFP_MOVABLE to keep draining/fragmenting U&R page blocks until they shrink to 12MB without enter slowpath which agai= nst current reclaiming policy. This commit change the criteria from hard coded = '1/2' to watermark check which leave U&R free pages stay around WMARK_LOW when be= ing fallback. DMA32 free:25900kB boost:0kB min:4176kB low:25856kB high:29516kB Signed-off-by: Zhaoyang Huang --- mm/page_alloc.c | 40 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 36 insertions(+), 4 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 0745aed..97768fe 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3071,6 +3071,39 @@ static bool unreserve_highatomic_pageblock(const str= uct alloc_context *ac, =20 } =20 +#ifdef CONFIG_CMA +static bool __if_use_cma_first(struct zone *zone, unsigned int order, unsi= gned int alloc_flags) +{ + unsigned long cma_proportion =3D 0; + unsigned long cma_free_proportion =3D 0; + unsigned long watermark =3D 0; + unsigned long wm_fact[ALLOC_WMARK_MASK] =3D {1, 1, 2}; + long count =3D 0; + bool cma_first =3D false; + + watermark =3D wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK); + /*check if GFP_MOVABLE pass previous watermark check via the help of CMA*/ + if (!zone_watermark_ok(zone, order, watermark, 0, alloc_flags & (~ALLOC_C= MA))) + { + alloc_flags &=3D ALLOC_WMARK_MASK; + /* WMARK_LOW failed lead to using cma first, this helps U&R stay + * around low when being drained by GFP_MOVABLE + */ + if (alloc_flags <=3D ALLOC_WMARK_LOW) + cma_first =3D true; + /*check proportion for WMARK_HIGH*/ + else { + count =3D atomic_long_read(&zone->managed_pages); + cma_proportion =3D zone->cma_pages * 100 / count; + cma_free_proportion =3D zone_page_state(zone, NR_FREE_CMA_PAGES) * 100 + / zone_page_state(zone, NR_FREE_PAGES); + cma_first =3D (cma_free_proportion >=3D wm_fact[alloc_flags] * cma_prop= ortion + || cma_free_proportion >=3D 50); + } + } + return cma_first; +} +#endif /* * Do the hard work of removing an element from the buddy allocator. * Call me with the zone->lock already held. @@ -3087,10 +3120,9 @@ static bool unreserve_highatomic_pageblock(const str= uct alloc_context *ac, * allocating from CMA when over half of the zone's free memory * is in the CMA area. */ - if (alloc_flags & ALLOC_CMA && - zone_page_state(zone, NR_FREE_CMA_PAGES) > - zone_page_state(zone, NR_FREE_PAGES) / 2) { - page =3D __rmqueue_cma_fallback(zone, order); + if (migratetype =3D=3D MIGRATE_MOVABLE) { + bool cma_first =3D __if_use_cma_first(zone, order, alloc_flags); + page =3D cma_first ? __rmqueue_cma_fallback(zone, order) : NULL; if (page) return page; } --=20 1.9.1