From patchwork Tue Jan 19 04:39:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pasha Tatashin X-Patchwork-Id: 12028609 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=-18.8 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,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 F0F79C433DB for ; Tue, 19 Jan 2021 04:46:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CEADE2222F for ; Tue, 19 Jan 2021 04:46:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733268AbhASEpW (ORCPT ); Mon, 18 Jan 2021 23:45:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387657AbhASEmU (ORCPT ); Mon, 18 Jan 2021 23:42:20 -0500 Received: from mail-qk1-x730.google.com (mail-qk1-x730.google.com [IPv6:2607:f8b0:4864:20::730]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BE83C0617BD for ; Mon, 18 Jan 2021 20:39:42 -0800 (PST) Received: by mail-qk1-x730.google.com with SMTP id b64so20773531qkc.12 for ; Mon, 18 Jan 2021 20:39:42 -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=Mozcc4kuYbrNkd78OelIwDi34wEitfuXZj+0y++fO7I=; b=nes348fen+42chjh/uf/Hck11INwC4iFF+XsgAEA6JHbTToYZq+aKmO9bDVdE+Lrmb wcdXVwEqY0eTMoP4wHR43h/1DOgUOy/LtJm5xPD3IlHDtJprVyXbWMz6SOw9FuwIdU73 Ed+0/ijhnsSsDFNP5U1BUpB+suSRTWJyi5I6qI0duiYrXzY7K1aw59rgkLXhyAIGA37k aIpWbLk+2Jxz51n6c4+fmw0vTapPA/zdo46f/yruQukd826LxWgTaw8LL1ONuOvTtN3I 6NF9IjGvqI0+5CTIrxPtxwbGMsFpLrduIO8IYFer47jbxzbGc48HQgDgBNyDhc5TZliz 3vEQ== 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=Mozcc4kuYbrNkd78OelIwDi34wEitfuXZj+0y++fO7I=; b=H7ZXtY3lmC7jfAqt+0Nqr1G9PFjkdbb04C/+t6IvNBPJ4nggYn0JnGdSzuV4LJ7zQ/ aax310fPn+IabO9L6T0cPzdm3TYVu/izUD9G5c4AyToBHmP/4S8umuBmnDtj67QQXahd scIBF7zFC4T6jB3NMI6ZieFz/D8ZSQv7pAHD5tHC/X294VMZISYyMUv4H3MyUWb1UgLl Pe4TPb2QViuT+9tEQePSk6cY3e8rEzBJvY2vpbbx55nTeCcsqngw0KVZHFVz9GuMFhMv xPNun2MtDD4V9ybNuo76KSwO8GKUvUT9DNoO/H8vN+EH9DYX8VtcoPErkLpoTUdXzGg6 5RPw== X-Gm-Message-State: AOAM532tZu2O8NmeoWoXDC9RAU4fo+eg0RPyi27JiwZgnRj/NymbssIE 8F29f3c0tFcD1xUJahitRTdHiZsWD4Aw2Q== X-Google-Smtp-Source: ABdhPJz+FNci4xuBDvj9gcDJx+dJbGOnd11aZ4ctDWNnJNtrR0jWNj8Mqh5wiA0py6oc3gJCr/ZP1Q== X-Received: by 2002:a37:e211:: with SMTP id g17mr2709283qki.298.1611031181530; Mon, 18 Jan 2021 20:39:41 -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 z20sm11934536qkz.37.2021.01.18.20.39.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Jan 2021 20:39:41 -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 Subject: [PATCH v5 12/14] mm/gup: longterm pin migration cleaup Date: Mon, 18 Jan 2021 23:39:18 -0500 Message-Id: <20210119043920.155044-13-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210119043920.155044-1-pasha.tatashin@soleen.com> References: <20210119043920.155044-1-pasha.tatashin@soleen.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org When pages are longterm pinned, we must migrated them out of movable zone. The function that migrates them has a hidden loop with goto. The loop is to retry on isolation failures, and after successful migration. Make this code better by moving this loop to the caller. Signed-off-by: Pavel Tatashin --- mm/gup.c | 101 +++++++++++++++++++++++-------------------------------- 1 file changed, 42 insertions(+), 59 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index dfe90b254bc6..3b46eb5fe3ba 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1548,27 +1548,28 @@ struct page *get_dump_page(unsigned long addr) } #endif /* CONFIG_ELF_CORE */ -static long check_and_migrate_movable_pages(struct mm_struct *mm, - unsigned long start, - unsigned long nr_pages, +/* + * Check whether all pages are pinnable, if so return number of pages. If some + * pages are not pinnable, migrate them, and unpin all pages. Return zero if + * pages were migrated, or if some pages were not successfully isolated. + * Return negative error if migration fails. + */ +static long check_and_migrate_movable_pages(unsigned long nr_pages, struct page **pages, - struct vm_area_struct **vmas, unsigned int gup_flags) { - unsigned long i, isolation_error_count; - bool drain_allow; + unsigned long i; + unsigned long isolation_error_count = 0; + bool drain_allow = true; LIST_HEAD(movable_page_list); - long ret = nr_pages; - struct page *prev_head, *head; + long ret = 0; + struct page *prev_head = NULL; + struct page *head; struct migration_target_control mtc = { .nid = NUMA_NO_NODE, .gfp_mask = GFP_USER | __GFP_NOWARN, }; -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) @@ -1606,40 +1607,23 @@ static long check_and_migrate_movable_pages(struct mm_struct *mm, * in the correct zone. */ if (list_empty(&movable_page_list) && !isolation_error_count) - return ret; + return nr_pages; + if (gup_flags & FOLL_PIN) { + unpin_user_pages(pages, nr_pages); + } else { + for (i = 0; i < nr_pages; i++) + put_page(pages[i]); + } if (!list_empty(&movable_page_list)) { - /* - * drop the above get_user_pages reference. - */ - if (gup_flags & FOLL_PIN) - unpin_user_pages(pages, nr_pages); - else - for (i = 0; i < nr_pages; i++) - put_page(pages[i]); - ret = migrate_pages(&movable_page_list, alloc_migration_target, NULL, (unsigned long)&mtc, MIGRATE_SYNC, MR_LONGTERM_PIN); - if (ret) { - if (!list_empty(&movable_page_list)) - putback_movable_pages(&movable_page_list); - return ret > 0 ? -ENOMEM : ret; - } - - /* 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; + if (ret && !list_empty(&movable_page_list)) + putback_movable_pages(&movable_page_list); } - /* - * check again because pages were unpinned, and we also might have - * had isolation errors and need more pages to migrate. - */ - goto check_again; + return ret > 0 ? -ENOMEM : ret; } /* @@ -1653,30 +1637,29 @@ static long __gup_longterm_locked(struct mm_struct *mm, struct vm_area_struct **vmas, unsigned int gup_flags) { - unsigned long flags = 0; + unsigned int flags; long rc; - if (gup_flags & FOLL_LONGTERM) { - /* - * We are long term pinning pages and their PA's should not - * change until unpinned. Without FOLL_WRITE we might get zero - * page which we do not want. Force creating normal - * pages by adding FOLL_WRITE. - */ - gup_flags |= FOLL_WRITE; - flags = memalloc_pin_save(); - } + if (!(gup_flags & FOLL_LONGTERM)) + return __get_user_pages_locked(mm, start, nr_pages, pages, vmas, + NULL, gup_flags); + /* + * We are long term pinning pages and their PA's should not change until + * unpinned. Without FOLL_WRITE we might get zero page which we do not + * want. Force creating normal pages by adding FOLL_WRITE. + */ + gup_flags |= FOLL_WRITE; + flags = memalloc_pin_save(); - rc = __get_user_pages_locked(mm, start, nr_pages, pages, vmas, NULL, - gup_flags); + do { + rc = __get_user_pages_locked(mm, start, nr_pages, pages, vmas, + NULL, gup_flags); + if (rc <= 0) + break; + rc = check_and_migrate_movable_pages(rc, pages, gup_flags); + } while (!rc); + memalloc_pin_restore(flags); - if (gup_flags & FOLL_LONGTERM) { - if (rc > 0) - rc = check_and_migrate_movable_pages(mm, start, rc, - pages, vmas, - gup_flags); - memalloc_pin_restore(flags); - } return rc; }