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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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 BBBF8C433DB for ; Mon, 4 Jan 2021 07:04:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D98020DD4 for ; Mon, 4 Jan 2021 07:04:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726733AbhADHEc (ORCPT ); Mon, 4 Jan 2021 02:04:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725889AbhADHEb (ORCPT ); Mon, 4 Jan 2021 02:04:31 -0500 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F146FC061574 for ; Sun, 3 Jan 2021 23:03:50 -0800 (PST) Received: by mail-pj1-x102a.google.com with SMTP id lb18so9456771pjb.5 for ; Sun, 03 Jan 2021 23:03:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=pO8eETMUuHslv7dgCvzXTlqPBwMMUJJFuNV+syZPPjo=; b=XX9nqxXjuf6vW9b2nopnCN21CK6HjbXrGfgHP1xJ+/xyeFEj6p/6SIm7sD0l2Hkaa9 d5d9f3VtSdHToGhL8wY1d59oxbbvVzB/U75YqxD5wYLzl7UoKjsqqPMbrNsQ74DyjUj3 sYAVf4KfRCEFTi7p5/epvifmtzeCTE+b90WhcHZ7DrIxm7ML79c9zaQvO9LS7Vj/pQ6t /2Z/4d7zZVOvqIM4HmiOTEiV9b4Ae8PajOlEb5wqC80XzkPvs+U/rBLLcbUS+DU68ccH fLm+KTglAN+jpQcbpIyDyJPHAvb6aDfPYtdwHn71sUXuM/ji7QNqh/UISDq11a5NcvEx DQIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=pO8eETMUuHslv7dgCvzXTlqPBwMMUJJFuNV+syZPPjo=; b=J2iU06suYAYwU/DD6q0OMCCY1S10Q/vePRc4gIxYxDhd7DeTNKUA9JgEKotMcDlK19 TE0jreVyxsVr4v0sjQdD9uEH+p2mDCibXIpqJPwdq4Q13DT43tVtBXxXj463kW4YgtJ4 v/v/MPG8vN8mwtFStNlKp/240W1Q7YkvlYma4PvxvBa102yJ7CASlvoPH/be4463dYI+ BLKAq8oU9VLm1Po5beLuqSEY1UV0MjzI0uOvp3K4ifY4i4BQjLUuzvVN76LRSGzLAgvc YJKrlcHP7VWYG2i7FY5zjUu6ZvVIRK1Jqd3xlnOBzTUPRPNnedbbNi4tjg/HEUN3CQlO gvDw== X-Gm-Message-State: AOAM531pH1v9lm2SxvyG9rX0vsiyoWQzxhIqvEINj+3s0BrSaiqU6/pk GC4lRN6I4uhMy8ULf9iJA8JeMw== X-Google-Smtp-Source: ABdhPJwqbxBxS5PJMCHoPtWr4TCCnEdAuUTeeZ5VgymgtCsqQHhK6TjTED8OZyw4Vu33BJFsAmKZfQ== X-Received: by 2002:a17:90b:23d6:: with SMTP id md22mr28061594pjb.206.1609743830555; Sun, 03 Jan 2021 23:03:50 -0800 (PST) Received: from localhost.localdomain ([240e:b1:e401:3::6]) by smtp.gmail.com with ESMTPSA id v1sm36306648pga.63.2021.01.03.23.02.33 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 03 Jan 2021 23:03:49 -0800 (PST) From: Muchun Song To: mike.kravetz@oracle.com, akpm@linux-foundation.org Cc: hillf.zj@alibaba-inc.com, n-horiguchi@ah.jp.nec.com, ak@linux.intel.com, yongjun_wei@trendmicro.com.cn, mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song Subject: [PATCH 4/6] mm: hugetlb: add return -EAGAIN for dissolve_free_huge_page Date: Mon, 4 Jan 2021 14:58:41 +0800 Message-Id: <20210104065843.5658-4-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210104065843.5658-1-songmuchun@bytedance.com> References: <20210104065843.5658-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When dissolve_free_huge_page() races with __free_huge_page(), we can do a retry. Because the race window is small. Signed-off-by: Muchun Song --- mm/hugetlb.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 72608008f8b4..db00ae375d2a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1763,10 +1763,11 @@ static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, * nothing for in-use hugepages and non-hugepages. * This function returns values like below: * - * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use - * (allocated or reserved.) - * 0: successfully dissolved free hugepages or the page is not a - * hugepage (considered as already dissolved) + * -EAGAIN: race with __free_huge_page() and can do a retry + * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use + * (allocated or reserved.) + * 0: successfully dissolved free hugepages or the page is not a + * hugepage (considered as already dissolved) */ int dissolve_free_huge_page(struct page *page) { @@ -1815,8 +1816,10 @@ int dissolve_free_huge_page(struct page *page) * We should make sure that the page is already on the free list * when it is dissolved. */ - if (unlikely(!PageHugeFreed(head))) + if (unlikely(!PageHugeFreed(head))) { + rc = -EAGAIN; goto out; + } /* * Move PageHWPoison flag from head page to the raw error page, @@ -1857,7 +1860,10 @@ int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) { page = pfn_to_page(pfn); +retry: rc = dissolve_free_huge_page(page); + if (rc == -EAGAIN) + goto retry; if (rc) break; } -- 2.11.0