From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4C3EEC433DB for ; Wed, 27 Jan 2021 10:22:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F101D20731 for ; Wed, 27 Jan 2021 10:22:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235839AbhA0KWg (ORCPT ); Wed, 27 Jan 2021 05:22:36 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:46042 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235777AbhA0KT5 (ORCPT ); Wed, 27 Jan 2021 05:19:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611742707; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LeueFFtmc2r/D9kvr3PLBuOowgUJrNaT10Vf8WSqmXE=; b=AoxYXZ90w7hy4dnwQbkk3CKWVdH836d7LjLjWUvbj2n0zPpZya0WmrGKCCBrU2dap089R0 rpXf5Tv8wz7dyF01jfISVwDuN7FG2giQYrCIwtJYK1vTHjsy4a0uH8gwU3kBKAaUjet1pY d/P92GwwGq77u/JFMWc88DfM9QgpfBw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-556-msfCqRKCPteJWQSiLSA3uw-1; Wed, 27 Jan 2021 05:18:23 -0500 X-MC-Unique: msfCqRKCPteJWQSiLSA3uw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E923A9CDA0; Wed, 27 Jan 2021 10:18:21 +0000 (UTC) Received: from t480s.redhat.com (ovpn-114-237.ams2.redhat.com [10.36.114.237]) by smtp.corp.redhat.com (Postfix) with ESMTP id E96E86EF55; Wed, 27 Jan 2021 10:18:19 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Andrew Morton , Thomas Gleixner , "Peter Zijlstra (Intel)" , Mike Rapoport , Oscar Salvador , Michal Hocko , Wei Yang Subject: [PATCH v1 1/2] mm/cma: expose all pages to the buddy if activation of an area fails Date: Wed, 27 Jan 2021 11:18:12 +0100 Message-Id: <20210127101813.6370-2-david@redhat.com> In-Reply-To: <20210127101813.6370-1-david@redhat.com> References: <20210127101813.6370-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Right now, if activation fails, we might already have exposed some pages to the buddy for CMA use (although they will never get actually used by CMA), and some pages won't be exposed to the buddy at all. Let's check for "single zone" early and on error, don't expose any pages for CMA use - instead, expose them to the buddy available for any use. Simply call free_reserved_page() on every single page - easier than going via free_reserved_area(), converting back and forth between pfns and virt addresses. In addition, make sure to fixup totalcma_pages properly. Example: 6 GiB QEMU VM with "... hugetlb_cma=2G movablecore=20% ...": [ 0.006891] hugetlb_cma: reserve 2048 MiB, up to 2048 MiB per node [ 0.006893] cma: Reserved 2048 MiB at 0x0000000100000000 [ 0.006893] hugetlb_cma: reserved 2048 MiB on node 0 ... [ 0.175433] cma: CMA area hugetlb0 could not be activated Before this patch: # cat /proc/meminfo MemTotal: 5867348 kB MemFree: 5692808 kB MemAvailable: 5542516 kB ... CmaTotal: 2097152 kB CmaFree: 1884160 kB After this patch: # cat /proc/meminfo MemTotal: 6077308 kB MemFree: 5904208 kB MemAvailable: 5747968 kB ... CmaTotal: 0 kB CmaFree: 0 kB Note: cma_init_reserved_mem() makes sure that we always cover full pageblocks / MAX_ORDER - 1 pages. Cc: Andrew Morton Cc: Thomas Gleixner Cc: "Peter Zijlstra (Intel)" Cc: Mike Rapoport Cc: Oscar Salvador Cc: Michal Hocko Cc: Wei Yang Signed-off-by: David Hildenbrand --- mm/cma.c | 43 +++++++++++++++++++++---------------------- 1 file changed, 21 insertions(+), 22 deletions(-) diff --git a/mm/cma.c b/mm/cma.c index 0ba69cd16aeb..23d4a97c834a 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -94,34 +94,29 @@ static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, static void __init cma_activate_area(struct cma *cma) { - unsigned long base_pfn = cma->base_pfn, pfn = base_pfn; - unsigned i = cma->count >> pageblock_order; + unsigned long base_pfn = cma->base_pfn, pfn; struct zone *zone; cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL); if (!cma->bitmap) goto out_error; - WARN_ON_ONCE(!pfn_valid(pfn)); - zone = page_zone(pfn_to_page(pfn)); - - do { - unsigned j; - - base_pfn = pfn; - for (j = pageblock_nr_pages; j; --j, pfn++) { - WARN_ON_ONCE(!pfn_valid(pfn)); - /* - * alloc_contig_range requires the pfn range - * specified to be in the same zone. Make this - * simple by forcing the entire CMA resv range - * to be in the same zone. - */ - if (page_zone(pfn_to_page(pfn)) != zone) - goto not_in_zone; - } - init_cma_reserved_pageblock(pfn_to_page(base_pfn)); - } while (--i); + /* + * alloc_contig_range() requires the pfn range specified to be in the + * same zone. Simplify by forcing the entire CMA resv range to be in the + * same zone. + */ + WARN_ON_ONCE(!pfn_valid(base_pfn)); + zone = page_zone(pfn_to_page(base_pfn)); + for (pfn = base_pfn + 1; pfn < base_pfn + cma->count; pfn++) { + WARN_ON_ONCE(!pfn_valid(pfn)); + if (page_zone(pfn_to_page(pfn)) != zone) + goto not_in_zone; + } + + for (pfn = base_pfn; pfn < base_pfn + cma->count; + pfn += pageblock_nr_pages) + init_cma_reserved_pageblock(pfn_to_page(pfn)); mutex_init(&cma->lock); @@ -135,6 +130,10 @@ static void __init cma_activate_area(struct cma *cma) not_in_zone: bitmap_free(cma->bitmap); out_error: + /* Expose all pages to the buddy, they are useless for CMA. */ + for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++) + free_reserved_page(pfn_to_page(pfn)); + totalcma_pages -= cma->count; cma->count = 0; pr_err("CMA area %s could not be activated\n", cma->name); return; -- 2.29.2