From patchwork Mon Jul 11 08:49:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Ying" X-Patchwork-Id: 12913154 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 A494ECCA47B for ; Mon, 11 Jul 2022 08:50:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B066E6B00A4; Mon, 11 Jul 2022 04:50:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AB7986B00A5; Mon, 11 Jul 2022 04:50:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 980286B00A6; Mon, 11 Jul 2022 04:50:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 8637C6B00A4 for ; Mon, 11 Jul 2022 04:50:06 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id 54CA0120647 for ; Mon, 11 Jul 2022 08:50:06 +0000 (UTC) X-FDA: 79674196812.04.BFE2676 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by imf16.hostedemail.com (Postfix) with ESMTP id 5B650180052 for ; Mon, 11 Jul 2022 08:50:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657529406; x=1689065406; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=1e+xGPIhxvMvpq200nX++mzDTD6BRkGQgKdN81HYoWs=; b=YiqpfRP+H8LbEGub87ImSPq5q43MMhd09fnNfE6TMpIIS1aNlezYXdob IbfOdwBZUHXoFPpQ1BrqKOg+Vbj3mlbM/K0jj3KcW8dtGkiUefuRJsT8k JNgrou5HUvz5n4NrzknGCAmy5jBTGx2zVEqCtFS1FgBqYLBf/kCnYj4fh M6YuNLm8DijFj1sTpGZwoJaQSkvi0puKZVyXdjdfTzm5mAxSyYpc15Vqo PbkLqQSjHjg0E2Cniyh4Ds3nDJfMhLqYEbTOePT/xkFI6yAO0koFA7R3b bOBUhA67LXtNENBHEwp4x4+Wzz7/7tCxIANfErgu2vulmq8UCcDvpl986 Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10404"; a="346296536" X-IronPort-AV: E=Sophos;i="5.92,262,1650956400"; d="scan'208";a="346296536" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jul 2022 01:50:04 -0700 X-IronPort-AV: E=Sophos;i="5.92,262,1650956400"; d="scan'208";a="652374085" Received: from yhuang6-mobl1.sh.intel.com ([10.238.5.168]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jul 2022 01:50:01 -0700 From: Huang Ying To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Huang, Ying" , Baolin Wang , Zi Yan , Yang Shi Subject: [PATCH -V2 0/7] migrate_pages(): fix several bugs in error path Date: Mon, 11 Jul 2022 16:49:41 +0800 Message-Id: <20220711084948.274787-1-ying.huang@intel.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=YiqpfRP+; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf16.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.31) smtp.mailfrom=ying.huang@intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657529406; 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:references:dkim-signature; bh=21B9kdhvPWLTahR0V/vGeb91cEyLzvUvcODDzW2NRVg=; b=NfjCWkAtBckXgIlF2VFHqtMnsLprYxl9ReuKqhY/4leLC9SKEklZkFvF6InBz2KfeKv2zr p9qM0LMg8gz5UOHwImI9TFW5o84nBCNE3C6dYFafwkioH9S7/CiM0IHna7gvZHHZtWB8kA TGaUoX/uX+vOkeypoJ4Ul353cNuKEHY= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657529406; a=rsa-sha256; cv=none; b=rOAgzJgDNcspnp/jfj8Dpu1XWM9wbz6gPue/EGyBDN60UqbqX5pzSWfKq+ksT0fv5Dj9bg E/HlAdbxbqRYrOiIEu49K8B6H+oGwq2Acok601mu/savbJnl23WOc+iJsZmIgSUqlgV4Gi qDv5iof+iJSRwgi9qsOKJDILoRUxukQ= Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=YiqpfRP+; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf16.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.31) smtp.mailfrom=ying.huang@intel.com X-Rspam-User: X-Rspamd-Server: rspam08 X-Stat-Signature: s949on4nbpq4tmx3a5y6yy83fcxsn9ko X-Rspamd-Queue-Id: 5B650180052 X-HE-Tag: 1657529405-909146 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: From: "Huang, Ying" During review the code of migrate_pages() and build a test program for it. Several bugs in error path are identified and fixed in this series. Most patches are tested via - Apply error-inject.patch in Linux kernel - Compile test-migrate.c (with -lnuma) - Test with test-migrate.sh error-inject.patch, test-migrate.c, and test-migrate.sh are as below. It turns out that error injection is an important tool to fix bugs in error path. Changes: v2: - Rebased on v5.19-rc5 - Addressed some comments from Baolin, Thanks! - Added reviewed-by tags Best Regards, Huang, Ying ------------------------- error-inject.patch ------------------------- From 295ea21204f3f025a041fe39c68a2eaec8313c68 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Tue, 21 Jun 2022 11:08:30 +0800 Subject: [PATCH] migrate_pages: error inject --- mm/migrate.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 55 insertions(+), 3 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 399904015d23..87d47064ec6c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -337,6 +337,42 @@ void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd) } #endif +#define EI_MP_ENOSYS 0x0001 +#define EI_MP_THP_ENOMEM 0x0002 +#define EI_MP_NP_ENOMEM 0x0004 +#define EI_MP_EAGAIN 0x0008 +#define EI_MP_EOTHER 0x0010 +#define EI_MP_NOSPLIT 0x0020 +#define EI_MP_SPLIT_FAIL 0x0040 +#define EI_MP_EAGAIN_PERM 0x0080 +#define EI_MP_EBUSY 0x0100 + +static unsigned int ei_migrate_pages; + +module_param(ei_migrate_pages, uint, 0644); + +static bool ei_thp_migration_supported(void) +{ + if (ei_migrate_pages & EI_MP_ENOSYS) + return false; + else + return thp_migration_supported(); +} + +static int ei_trylock_page(struct page *page) +{ + if (ei_migrate_pages & EI_MP_EAGAIN) + return 0; + return trylock_page(page); +} + +static int ei_split_huge_page_to_list(struct page *page, struct list_head *list) +{ + if (ei_migrate_pages & EI_MP_SPLIT_FAIL) + return -EBUSY; + return split_huge_page_to_list(page, list); +} + static int expected_page_refs(struct address_space *mapping, struct page *page) { int expected_count = 1; @@ -368,6 +404,9 @@ int folio_migrate_mapping(struct address_space *mapping, if (folio_ref_count(folio) != expected_count) return -EAGAIN; + if (ei_migrate_pages & EI_MP_EAGAIN_PERM) + return -EAGAIN; + /* No turning back from here */ newfolio->index = folio->index; newfolio->mapping = folio->mapping; @@ -929,7 +968,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, struct anon_vma *anon_vma = NULL; bool is_lru = !__PageMovable(page); - if (!trylock_page(page)) { + if (!ei_trylock_page(page)) { if (!force || mode == MIGRATE_ASYNC) goto out; @@ -952,6 +991,11 @@ static int __unmap_and_move(struct page *page, struct page *newpage, lock_page(page); } + if (ei_migrate_pages & EI_MP_EBUSY) { + rc = -EBUSY; + goto out_unlock; + } + if (PageWriteback(page)) { /* * Only in the case of a full synchronous migration is it @@ -1086,7 +1130,7 @@ static int unmap_and_move(new_page_t get_new_page, int rc = MIGRATEPAGE_SUCCESS; struct page *newpage = NULL; - if (!thp_migration_supported() && PageTransHuge(page)) + if (!ei_thp_migration_supported() && PageTransHuge(page)) return -ENOSYS; if (page_count(page) == 1) { @@ -1102,6 +1146,11 @@ static int unmap_and_move(new_page_t get_new_page, goto out; } + if ((ei_migrate_pages & EI_MP_THP_ENOMEM) && PageTransHuge(page)) + return -ENOMEM; + if ((ei_migrate_pages & EI_MP_NP_ENOMEM) && !PageTransHuge(page)) + return -ENOMEM; + newpage = get_new_page(page, private); if (!newpage) return -ENOMEM; @@ -1305,7 +1354,7 @@ static inline int try_split_thp(struct page *page, struct list_head *split_pages int rc; lock_page(page); - rc = split_huge_page_to_list(page, split_pages); + rc = ei_split_huge_page_to_list(page, split_pages); unlock_page(page); return rc; @@ -1358,6 +1407,9 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, bool nosplit = (reason == MR_NUMA_MISPLACED); bool no_subpage_counting = false; + if (ei_migrate_pages & EI_MP_NOSPLIT) + nosplit = true; + trace_mm_migrate_pages_start(mode, reason); thp_subpage_migration: