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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1758C433EF for ; Mon, 27 Dec 2021 14:08:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237040AbhL0OIr (ORCPT ); Mon, 27 Dec 2021 09:08:47 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:35908 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237016AbhL0OIp (ORCPT ); Mon, 27 Dec 2021 09:08:45 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7459B6102D for ; Mon, 27 Dec 2021 14:08:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5946FC36AE7; Mon, 27 Dec 2021 14:08:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1640614124; bh=UgYEEXvEur/CRVFSKpN3xyEKKrBJjqaADBJHVbxWBWE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=THI3QGQmqbQg9lfU5NuobI4OYvXEJsBYZNT2OksZfVXRUFpi5cRSc3RjxbbCSfXRH WXXDI7eBfua8L9N/jJrvuYbl5XUHfXRJdldrrn10NCxFBmwAgeijFbkNDHr2kYI8yq IzkqKsgLQ5Rmh0rdQQdVVShWnn7khubQwfVYUBjk= Date: Mon, 27 Dec 2021 15:08:42 +0100 From: Greg KH To: Andrey Ryabinin Cc: stable@vger.kernel.org, aarcange@redhat.com, akpm@linux-foundation.org, mgorman@techsingularity.net, mhocko@suse.com, rientjes@google.com, torvalds@linux-foundation.org Subject: Re: [PATCH 5.4] mm: mempolicy: fix THP allocations escaping mempolicy restrictions Message-ID: References: <1640608459160181@kroah.com> <20211227134539.1447-1-arbn@yandex-team.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211227134539.1447-1-arbn@yandex-team.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Dec 27, 2021 at 04:45:39PM +0300, Andrey Ryabinin wrote: > commit 338635340669d5b317c7e8dcf4fff4a0f3651d87 upstream. > > alloc_pages_vma() may try to allocate THP page on the local NUMA node > first: > > page = __alloc_pages_node(hpage_node, > gfp | __GFP_THISNODE | __GFP_NORETRY, order); > > And if the allocation fails it retries allowing remote memory: > > if (!page && (gfp & __GFP_DIRECT_RECLAIM)) > page = __alloc_pages_node(hpage_node, > gfp, order); > > However, this retry allocation completely ignores memory policy nodemask > allowing allocation to escape restrictions. > > The first appearance of this bug seems to be the commit ac5b2c18911f > ("mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings"). > > The bug disappeared later in the commit 89c83fb539f9 ("mm, thp: > consolidate THP gfp handling into alloc_hugepage_direct_gfpmask") and > reappeared again in slightly different form in the commit 76e654cc91bb > ("mm, page_alloc: allow hugepage fallback to remote nodes when > madvised") > > Fix this by passing correct nodemask to the __alloc_pages() call. > > The demonstration/reproducer of the problem: > > $ mount -oremount,size=4G,huge=always /dev/shm/ > $ echo always > /sys/kernel/mm/transparent_hugepage/defrag > $ cat mbind_thp.c > #include > #include > #include > #include > #include > #include > #include > #include > > #define SIZE 2ULL << 30 > int main(int argc, char **argv) > { > int fd; > unsigned long long i; > char *addr; > pid_t pid; > char buf[100]; > unsigned long nodemask = 1; > > fd = open("/dev/shm/test", O_RDWR|O_CREAT); > assert(fd > 0); > assert(ftruncate(fd, SIZE) == 0); > > addr = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, > MAP_SHARED, fd, 0); > > assert(mbind(addr, SIZE, MPOL_BIND, &nodemask, 2, MPOL_MF_STRICT|MPOL_MF_MOVE)==0); > for (i = 0; i < SIZE; i+=4096) { > addr[i] = 1; > } > pid = getpid(); > snprintf(buf, sizeof(buf), "grep shm /proc/%d/numa_maps", pid); > system(buf); > sleep(10000); > > return 0; > } > $ gcc mbind_thp.c -o mbind_thp -lnuma > $ numactl -H > available: 2 nodes (0-1) > node 0 cpus: 0 2 > node 0 size: 1918 MB > node 0 free: 1595 MB > node 1 cpus: 1 3 > node 1 size: 2014 MB > node 1 free: 1731 MB > node distances: > node 0 1 > 0: 10 20 > 1: 20 10 > $ rm -f /dev/shm/test; taskset -c 0 ./mbind_thp > 7fd970a00000 bind:0 file=/dev/shm/test dirty=524288 active=0 N0=396800 N1=127488 kernelpagesize_kB=4 > > Link: https://lkml.kernel.org/r/20211208165343.22349-1-arbn@yandex-team.com > Fixes: ac5b2c18911f ("mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings") > Signed-off-by: Andrey Ryabinin > Acked-by: Michal Hocko > Acked-by: Mel Gorman > Acked-by: David Rientjes > Cc: Andrea Arcangeli > Signed-off-by: Andrew Morton > Signed-off-by: Linus Torvalds > Signed-off-by: Andrey Ryabinin > --- > mm/mempolicy.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) Both backports now queued up, thanks. greg k-h