From patchwork Mon Feb 1 15:38:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pasha Tatashin X-Patchwork-Id: 374405 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=-18.7 required=3.0 tests=BAYES_00,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, USER_AGENT_GIT 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 076CEC433E0 for ; Mon, 1 Feb 2021 15:44:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C68CF64DE1 for ; Mon, 1 Feb 2021 15:44:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231494AbhBAPoh (ORCPT ); Mon, 1 Feb 2021 10:44:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231248AbhBAPjx (ORCPT ); Mon, 1 Feb 2021 10:39:53 -0500 Received: from mail-qk1-x732.google.com (mail-qk1-x732.google.com [IPv6:2607:f8b0:4864:20::732]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7BCCC061797 for ; Mon, 1 Feb 2021 07:38:37 -0800 (PST) Received: by mail-qk1-x732.google.com with SMTP id s77so3179785qke.4 for ; Mon, 01 Feb 2021 07:38:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=g2firNhV/7kB7YU7cH9BNSgXaQWIxvW5HlS98FNnYEs=; b=cQ7U9FQRpR9JGNNrg7Wiu9qDQUW+pR4nvGFdzAwg72lQTYccPZx1dsnRYuei2XGHR2 nAlpPdY8DvOXXmWhxdO2LVpkkk/LE3TWy1gnwdN9NGZ27+5o4ziEIQHINofLGI6f/ljN xUImvXDI5GxWSaIoGrqJ9WAUFPoBXi7P8YlKOIrlNG9bSr0jV22PcDOKtLdrgcVa/eSO npZal8wKnZ01rdB2fiGFC5d7sGwMqK/gqvcw9nRH7m7NG7fVylYebScPZJ8QRLAfJrjp 31zojxu9KuEQTeGfWRsA44sPb9srl/ktRriq5tGaxbxyU+o/nPqqMqtR4G4Ch4hpcFXK bCsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=g2firNhV/7kB7YU7cH9BNSgXaQWIxvW5HlS98FNnYEs=; b=fknKFDMUrMaRpjpatlSnd1FPlb0C/6Hy1+xCfhiDsjepFByXi7/GRW1ifRtpXo5HAG ZbPqvMj/tRg/59nV6PiDo9KFfWw/2IrW/aP/6HgNpsGDyC1l+AyDo+ZTJReRZBgybQNI cCAjIMtNWiIJbOwp3IeeH1+jsrV+8K2KQeAtCxa2Gngdph4cn5PnZnfIOdnQze3g5R0A VId7FP+rvBKFeAfYwxZ2rXSg2/A12MbLB/HA3rUAD2X3onezc4g31XDL6WrxT1fzaBUB x349teTiTU7wyT5qq3qBoMDWh9qf0+XZyZ2OiYQJ17v2ybHyZc+rWwPYZOhGnmw0+WI9 SkDQ== X-Gm-Message-State: AOAM532GjPrzbNSN9wrferS+ZjYdIy8bwbjoPMbbOXcMjhjfOK9M06ly OgVNeysR0kmu29HVPOAoczQWWw== X-Google-Smtp-Source: ABdhPJz3cHryVBgm+sMaWB1E3xhYlRhY35s+BzBXgbN2R53/Sw/rzB5M+lv25DSTo/3rnxq17/J76A== X-Received: by 2002:a37:4d12:: with SMTP id a18mr16245768qkb.371.1612193916967; Mon, 01 Feb 2021 07:38:36 -0800 (PST) Received: from localhost.localdomain (c-73-69-118-222.hsd1.nh.comcast.net. [73.69.118.222]) by smtp.gmail.com with ESMTPSA id 22sm14853307qke.123.2021.02.01.07.38.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Feb 2021 07:38:36 -0800 (PST) From: Pavel Tatashin To: pasha.tatashin@soleen.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz, mhocko@suse.com, david@redhat.com, osalvador@suse.de, dan.j.williams@intel.com, sashal@kernel.org, tyhicks@linux.microsoft.com, iamjoonsoo.kim@lge.com, mike.kravetz@oracle.com, rostedt@goodmis.org, mingo@redhat.com, jgg@ziepe.ca, peterz@infradead.org, mgorman@suse.de, willy@infradead.org, rientjes@google.com, jhubbard@nvidia.com, linux-doc@vger.kernel.org, ira.weiny@intel.com, linux-kselftest@vger.kernel.org, jmorris@namei.org Subject: [PATCH v9 04/14] mm/gup: check for isolation errors Date: Mon, 1 Feb 2021 10:38:17 -0500 Message-Id: <20210201153827.444374-5-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210201153827.444374-1-pasha.tatashin@soleen.com> References: <20210201153827.444374-1-pasha.tatashin@soleen.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org It is still possible that we pin movable CMA pages if there are isolation errors and cma_page_list stays empty when we check again. Check for isolation errors, and return success only when there are no isolation errors, and cma_page_list is empty after checking. Because isolation errors are transient, we retry indefinitely. Fixes: 9a4e9f3b2d73 ("mm: update get_user_pages_longterm to migrate pages allocated from CMA region") Signed-off-by: Pavel Tatashin Reviewed-by: Jason Gunthorpe --- mm/gup.c | 60 ++++++++++++++++++++++++++++++++------------------------ 1 file changed, 34 insertions(+), 26 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 88ce41f41543..7ecca2d66dff 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1555,8 +1555,8 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, struct vm_area_struct **vmas, unsigned int gup_flags) { - unsigned long i; - bool drain_allow = true; + unsigned long i, isolation_error_count; + bool drain_allow; LIST_HEAD(cma_page_list); long ret = nr_pages; struct page *prev_head, *head; @@ -1567,6 +1567,8 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, check_again: prev_head = NULL; + isolation_error_count = 0; + drain_allow = true; for (i = 0; i < nr_pages; i++) { head = compound_head(pages[i]); if (head == prev_head) @@ -1578,25 +1580,35 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, * of the CMA zone if possible. */ if (is_migrate_cma_page(head)) { - if (PageHuge(head)) - isolate_huge_page(head, &cma_page_list); - else { + if (PageHuge(head)) { + if (!isolate_huge_page(head, &cma_page_list)) + isolation_error_count++; + } else { if (!PageLRU(head) && drain_allow) { lru_add_drain_all(); drain_allow = false; } - if (!isolate_lru_page(head)) { - list_add_tail(&head->lru, &cma_page_list); - mod_node_page_state(page_pgdat(head), - NR_ISOLATED_ANON + - page_is_file_lru(head), - thp_nr_pages(head)); + if (isolate_lru_page(head)) { + isolation_error_count++; + continue; } + list_add_tail(&head->lru, &cma_page_list); + mod_node_page_state(page_pgdat(head), + NR_ISOLATED_ANON + + page_is_file_lru(head), + thp_nr_pages(head)); } } } + /* + * If list is empty, and no isolation errors, means that all pages are + * in the correct zone. + */ + if (list_empty(&cma_page_list) && !isolation_error_count) + return ret; + if (!list_empty(&cma_page_list)) { /* * drop the above get_user_pages reference. @@ -1616,23 +1628,19 @@ static long check_and_migrate_cma_pages(struct mm_struct *mm, return ret > 0 ? -ENOMEM : ret; } - /* - * We did migrate all the pages, Try to get the page references - * again migrating any new CMA pages which we failed to isolate - * earlier. - */ - ret = __get_user_pages_locked(mm, start, nr_pages, - pages, vmas, NULL, - gup_flags); - - if (ret > 0) { - nr_pages = ret; - drain_allow = true; - goto check_again; - } + /* We unpinned pages before migration, pin them again */ + ret = __get_user_pages_locked(mm, start, nr_pages, pages, vmas, + NULL, gup_flags); + if (ret <= 0) + return ret; + nr_pages = ret; } - return ret; + /* + * check again because pages were unpinned, and we also might have + * had isolation errors and need more pages to migrate. + */ + goto check_again; } #else static long check_and_migrate_cma_pages(struct mm_struct *mm,