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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7776C32772 for ; Wed, 17 Aug 2022 08:14:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DF6478D0003; Wed, 17 Aug 2022 04:14:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D7CA78D0001; Wed, 17 Aug 2022 04:14:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BCEAE8D0003; Wed, 17 Aug 2022 04:14:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id B03848D0001 for ; Wed, 17 Aug 2022 04:14:25 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 7D242A03E4 for ; Wed, 17 Aug 2022 08:14:25 +0000 (UTC) X-FDA: 79808372490.14.2A6D28A Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by imf21.hostedemail.com (Postfix) with ESMTP id E21D71C01F2 for ; Wed, 17 Aug 2022 08:14:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660724064; x=1692260064; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=xjmwUhmqYGhaMRwm5D3DkxjF2iYcxiuJ/Jn14RhEMRc=; b=eVxdgSvSW0q4aTjDZ1TslBq0f6r/eA+x9UdjA2B98GAAbICu/cuAZRAv 3agb0cCZFyN7HNfPgPGWFe4xilgFbKlLL4IhNVmO6kIt4jr99bkwwf6z7 9px9Z8c2zEGdi8pJ9V1B31qL5OeKFCgtqnt/AKoR5xKYBP/K4gnfN7WwL koudTlfpmKIgEZ0xw0AO4UoEmM9Ae8m5NX38s7XotOmZKQGxTQ0uhCHu/ feP8J00t3BQ2/abNwqg6yr0ct1b1yziKNDD0x9b7k2/r0t9OU+EmZp9z3 qjX7reDbKGfGjHhlks4uQnVCtZxV38aoPeIBMThyi1grTkHw552MAGoHY Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10441"; a="293710770" X-IronPort-AV: E=Sophos;i="5.93,242,1654585200"; d="scan'208";a="293710770" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Aug 2022 01:14:23 -0700 X-IronPort-AV: E=Sophos;i="5.93,242,1654585200"; d="scan'208";a="583668075" Received: from yhuang6-mobl1.sh.intel.com ([10.238.6.172]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Aug 2022 01:14:21 -0700 From: Huang Ying To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Oscar Salvador , Baolin Wang , Zi Yan , Yang Shi Subject: [PATCH -V3 1/8] migrate: fix syscall move_pages() return value for failure Date: Wed, 17 Aug 2022 16:14:01 +0800 Message-Id: <20220817081408.513338-2-ying.huang@intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220817081408.513338-1-ying.huang@intel.com> References: <20220817081408.513338-1-ying.huang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660724065; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=epU+Qv3p1YaWrIBOTr/p7waIlCtL9i+O0jnMIHmixdk=; b=I8RyW1nbonICGKNGWiK5RXgB3JmAbcfPpxYiNFEalniiXbGD4bftegBN5tx9vtBimMzjsz 5zjjoZ/TqWDFga2oLlIp93DLkx5f4o4XCNERi9u13TzGNkpHPRzx+UcGOzBj+78YW1SabU VPwgwK1PU/Wk8nWxSjuS/Gz2yDQgO2s= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=eVxdgSvS; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf21.hostedemail.com: domain of ying.huang@intel.com designates 134.134.136.65 as permitted sender) smtp.mailfrom=ying.huang@intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660724065; a=rsa-sha256; cv=none; b=rSN/OSefeSYN5NkXAr3WGjFa2xJ7bUbavGuRsK3flcJfLUxK0gbMRDnqT4R8CWFSfMztD7 hSM5aKEQsEe9IedWsjzG6XG9nez3zibgqzgkDM6gFOwIfBUB37yf1KDPk5w5LgZ/61/SOy 7gqieH9dcTdwXaWkyNINf6YwOsuG5rA= Authentication-Results: imf21.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=eVxdgSvS; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf21.hostedemail.com: domain of ying.huang@intel.com designates 134.134.136.65 as permitted sender) smtp.mailfrom=ying.huang@intel.com X-Rspam-User: X-Stat-Signature: cywayaf3sq5qiryahy8dct6dtzzwpabp X-Rspamd-Queue-Id: E21D71C01F2 X-Rspamd-Server: rspam11 X-HE-Tag: 1660724064-902794 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: The return value of move_pages() syscall is incorrect when counting the remaining pages to be migrated. For example, for the following test program, " #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #ifndef MADV_FREE #define MADV_FREE 8 /* free pages only if memory pressure */ #endif #define ONE_MB (1024 * 1024) #define MAP_SIZE (16 * ONE_MB) #define THP_SIZE (2 * ONE_MB) #define THP_MASK (THP_SIZE - 1) #define ERR_EXIT_ON(cond, msg) \ do { \ int __cond_in_macro = (cond); \ if (__cond_in_macro) \ error_exit(__cond_in_macro, (msg)); \ } while (0) void error_msg(int ret, int nr, int *status, const char *msg) { int i; fprintf(stderr, "Error: %s, ret : %d, error: %s\n", msg, ret, strerror(errno)); if (!nr) return; fprintf(stderr, "status: "); for (i = 0; i < nr; i++) fprintf(stderr, "%d ", status[i]); fprintf(stderr, "\n"); } void error_exit(int ret, const char *msg) { error_msg(ret, 0, NULL, msg); exit(1); } int page_size; bool do_vmsplice; bool do_thp; static int pipe_fds[2]; void *addr; char *pn; char *pn1; void *pages[2]; int status[2]; void prepare() { int ret; struct iovec iov; if (addr) { munmap(addr, MAP_SIZE); close(pipe_fds[0]); close(pipe_fds[1]); } ret = pipe(pipe_fds); ERR_EXIT_ON(ret, "pipe"); addr = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); ERR_EXIT_ON(addr == MAP_FAILED, "mmap"); if (do_thp) { ret = madvise(addr, MAP_SIZE, MADV_HUGEPAGE); ERR_EXIT_ON(ret, "advise hugepage"); } pn = (char *)(((unsigned long)addr + THP_SIZE) & ~THP_MASK); pn1 = pn + THP_SIZE; pages[0] = pn; pages[1] = pn1; *pn = 1; if (do_vmsplice) { iov.iov_base = pn; iov.iov_len = page_size; ret = vmsplice(pipe_fds[1], &iov, 1, 0); ERR_EXIT_ON(ret < 0, "vmsplice"); } status[0] = status[1] = 1024; } void test_migrate() { int ret; int nodes[2] = { 1, 1 }; pid_t pid = getpid(); prepare(); ret = move_pages(pid, 1, pages, nodes, status, MPOL_MF_MOVE_ALL); error_msg(ret, 1, status, "move 1 page"); prepare(); ret = move_pages(pid, 2, pages, nodes, status, MPOL_MF_MOVE_ALL); error_msg(ret, 2, status, "move 2 pages, page 1 not mapped"); prepare(); *pn1 = 1; ret = move_pages(pid, 2, pages, nodes, status, MPOL_MF_MOVE_ALL); error_msg(ret, 2, status, "move 2 pages"); prepare(); *pn1 = 1; nodes[1] = 0; ret = move_pages(pid, 2, pages, nodes, status, MPOL_MF_MOVE_ALL); error_msg(ret, 2, status, "move 2 pages, page 1 to node 0"); } int main(int argc, char *argv[]) { numa_run_on_node(0); page_size = getpagesize(); test_migrate(); fprintf(stderr, "\nMake page 0 cannot be migrated:\n"); do_vmsplice = true; test_migrate(); fprintf(stderr, "\nTest THP:\n"); do_thp = true; do_vmsplice = false; test_migrate(); fprintf(stderr, "\nTHP: make page 0 cannot be migrated:\n"); do_vmsplice = true; test_migrate(); return 0; } " The output of the current kernel is, " Error: move 1 page, ret : 0, error: Success status: 1 Error: move 2 pages, page 1 not mapped, ret : 0, error: Success status: 1 -14 Error: move 2 pages, ret : 0, error: Success status: 1 1 Error: move 2 pages, page 1 to node 0, ret : 0, error: Success status: 1 0 Make page 0 cannot be migrated: Error: move 1 page, ret : 0, error: Success status: 1024 Error: move 2 pages, page 1 not mapped, ret : 1, error: Success status: 1024 -14 Error: move 2 pages, ret : 0, error: Success status: 1024 1024 Error: move 2 pages, page 1 to node 0, ret : 1, error: Success status: 1024 1024 " While the expected output is, " Error: move 1 page, ret : 0, error: Success status: 1 Error: move 2 pages, page 1 not mapped, ret : 0, error: Success status: 1 -14 Error: move 2 pages, ret : 0, error: Success status: 1 1 Error: move 2 pages, page 1 to node 0, ret : 0, error: Success status: 1 0 Make page 0 cannot be migrated: Error: move 1 page, ret : 1, error: Success status: 1024 Error: move 2 pages, page 1 not mapped, ret : 1, error: Success status: 1024 -14 Error: move 2 pages, ret : 1, error: Success status: 1024 1024 Error: move 2 pages, page 1 to node 0, ret : 2, error: Success status: 1024 1024 " Fix this via correcting the remaining pages counting. With the fix, the output for the test program as above is expected. Signed-off-by: "Huang, Ying" Fixes: 5984fabb6e82 ("mm: move_pages: report the number of non-attempted pages") Reviewed-by: Oscar Salvador Cc: Baolin Wang Cc: Zi Yan Cc: Yang Shi --- mm/migrate.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index a35eba462e61..1758fd215c0a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1751,7 +1751,7 @@ static int move_pages_and_store_status(struct mm_struct *mm, int node, * well. */ if (err > 0) - err += nr_pages - i - 1; + err += nr_pages - i; return err; } return store_status(status, start, node, i - start); @@ -1837,8 +1837,12 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, err = move_pages_and_store_status(mm, current_node, &pagelist, status, start, i, nr_pages); - if (err) + if (err) { + /* We have accounted for page i */ + if (err > 0) + err--; goto out; + } current_node = NUMA_NO_NODE; } out_flush: -- 2.30.2