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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 7DB40C55178 for ; Thu, 5 Nov 2020 19:15:29 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EE53B2087D for ; Thu, 5 Nov 2020 19:15:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EE53B2087D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 761EA6B0183; Thu, 5 Nov 2020 14:15:28 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 733B76B0186; Thu, 5 Nov 2020 14:15:28 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6722A6B0187; Thu, 5 Nov 2020 14:15:28 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0087.hostedemail.com [216.40.44.87]) by kanga.kvack.org (Postfix) with ESMTP id 38FDC6B0183 for ; Thu, 5 Nov 2020 14:15:28 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id D1675824999B for ; Thu, 5 Nov 2020 19:15:27 +0000 (UTC) X-FDA: 77451318294.18.tray25_2606681272cc Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin18.hostedemail.com (Postfix) with ESMTP id 84740100ED0E4 for ; Thu, 5 Nov 2020 19:15:27 +0000 (UTC) X-HE-Tag: tray25_2606681272cc X-Filterd-Recvd-Size: 2905 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Nov 2020 19:15:26 +0000 (UTC) Received: from imladris.surriel.com ([96.67.55.152]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1kakj1-00048T-FN; Thu, 05 Nov 2020 14:15:11 -0500 From: Rik van Riel To: hughd@google.com Cc: xuyu@linux.alibaba.com, akpm@linux-foundation.org, mgorman@suse.de, aarcange@redhat.com, willy@infradead.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, linux-mm@kvack.org, vbabka@suse.cz, mhocko@suse.com, Rik van Riel Subject: [PATCH 2/2] mm,thp,shm: limit gfp mask to no more than specified Date: Thu, 5 Nov 2020 14:15:08 -0500 Message-Id: <20201105191508.1961686-3-riel@surriel.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20201105191508.1961686-1-riel@surriel.com> References: <20201105191508.1961686-1-riel@surriel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Matthew Wilcox pointed out that the i915 driver opportunistically allocates tmpfs memory, but will happily reclaim some of its pool if no memory is available. Make sure the gfp mask used to opportunistically allocate a THP is always at least as restrictive as the original gfp mask. Signed-off-by: Rik van Riel Suggested-by: Matthew Wilcox --- mm/shmem.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/mm/shmem.c b/mm/shmem.c index 6c3cb192a88d..ee3cea10c2a4 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1531,6 +1531,26 @@ static struct page *shmem_swapin(swp_entry_t swap,= gfp_t gfp, return page; } =20 +/* + * Make sure huge_gfp is always more limited than limit_gfp. + * Some of the flags set permissions, while others set limitations. + */ +static gfp_t limit_gfp_mask(gfp_t huge_gfp, gfp_t limit_gfp) +{ + gfp_t allowflags =3D __GFP_IO | __GFP_FS | __GFP_RECLAIM; + gfp_t denyflags =3D __GFP_NOWARN | __GFP_NORETRY; + gfp_t result =3D huge_gfp & ~allowflags; + + /* + * Minimize the result gfp by taking the union with the deny flags, + * and the intersection of the allow flags. + */ + result |=3D (limit_gfp & denyflags); + result |=3D (huge_gfp & limit_gfp) & allowflags; + + return result; +} + static struct page *shmem_alloc_hugepage(gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { @@ -1889,6 +1909,7 @@ static int shmem_getpage_gfp(struct inode *inode, p= goff_t index, =20 alloc_huge: huge_gfp =3D vma_thp_gfp_mask(vma); + huge_gfp =3D limit_gfp_mask(huge_gfp, gfp); page =3D shmem_alloc_and_acct_page(huge_gfp, inode, index, true); if (IS_ERR(page)) { alloc_nohuge: --=20 2.25.4