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d=hostedemail.com; s=arc-20220608; t=1747123551; 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; bh=Lz4roueWshpXbH4hQmTNJ2+VJOVr0FoecaFurIPoHxY=; b=76y6GaETwACyD3PFUohBixKZsRYxjHUDW0wdBoVrhxxSAvGxDtUPJ0Pt/zzMv58xoeYz/F 1/qKGA064ocvHiB7N851gQ2WP5x6qTf01bAIqOBmrjbNEPz452uK4qVGhwgnDsof0qGHoG tx590URjWnexQQaW43Luu4MZs8G0mhY= Received: from loongson.cn (unknown [223.64.68.186]) by gateway (Coremail) with SMTP id _____8AxDGtY_SJo1pzjAA--.43255S3; Tue, 13 May 2025 16:05:44 +0800 (CST) Received: from localhost.localdomain (unknown [223.64.68.186]) by front1 (Coremail) with SMTP id qMiowMDxPBtN_SJofXTNAA--.18011S2; Tue, 13 May 2025 16:05:36 +0800 (CST) From: Huacai Chen To: Greg Kroah-Hartman , Sasha Levin , Huacai Chen Cc: Xuerui Wang , stable@vger.kernel.org, Andrew Morton , linux-mm@kvack.org, loongarch@lists.linux.dev, Zi Yan , Huang Ying , Baolin Wang , David Hildenbrand , Matthew Wilcox , Huacai Chen Subject: [PATCH for 6.6] mm/migrate: correct nr_failed in migrate_pages_sync() Date: Tue, 13 May 2025 16:05:21 +0800 Message-ID: <20250513080521.252543-1-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.47.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:qMiowMDxPBtN_SJofXTNAA--.18011S2 X-CM-SenderInfo: hfkh0x5xdftxo6or00hjvr0hdfq/ X-Coremail-Antispam: 1Uk129KBj93XoWxXr1UtrW3ZrykCr1fAw1fuFX_yoWrCw4rpF 4Igw1qyrW8XrWvgasxtryqkFnxCrZxZr43Ja4xGryrtFsxX3sFkrWfGayqyF4rKry2van3 JF4qgF1Y9ay8XrcCm3ZEXasCq-sJn29KB7ZKAUJUUUUr529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUvKb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ GcCE3s1ln4kS14v26r1Y6r17M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2 x26I8E6xACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1Y6r17 McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr4 1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1l4IxYO2xFxVAFwI0_Jrv_ JF1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17 CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0 I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I 8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU 0xZFpf9x07jFa0PUUUUU= X-Stat-Signature: zionr7bjihombjaa3hdzopsxg8mn9boj X-Rspam-User: X-Rspamd-Queue-Id: F0ED640008 X-Rspamd-Server: rspam06 X-HE-Tag: 1747123549-175749 X-HE-Meta: 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 GBhjtpSy GrccMMjmu+u4I1Li1gRMgqKqlaZHBus9QhHBHSNLp/hFPD7wQLZ0zLpua0rJvXDQbi76glUeVgkhvIsCI6AcCHke1Ynx8eDHKWTKxSgx+fgD+qzFHrUQ+k1tzCRG3HlyMKoE5XXN2bzujNVyMWgwtt0f3A6745iPSG8y2yp2gmAKzYOFuxxAzOr0E4+a3ZAbiEhMv5uUMc2b6MZ7bjD/PCHWPOAwS9lJahbwrWTOdT3qJkE8b9Rue7H7xCZh8WbzFlyer4MD57xmnQwJYR5WweiIJEKY5FWYqv+LC9eG/ZtAP8VQvFyu8yOTSJch3p034o5ugtP2kEpNAOYTTuFnkJMF10xEYvmjkdLyPxffPZCKCNZhh38n12hJHHJli9UU4vo5y 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: List-Subscribe: List-Unsubscribe: From: Zi Yan nr_failed was missing the large folio splits from migrate_pages_batch() and can cause a mismatch between migrate_pages() return value and the number of not migrated pages, i.e., when the return value of migrate_pages() is 0, there are still pages left in the from page list. It will happen when a non-PMD THP large folio fails to migrate due to -ENOMEM and is split successfully but not all the split pages are not migrated, migrate_pages_batch() would return non-zero, but astats.nr_thp_split = 0. nr_failed would be 0 and returned to the caller of migrate_pages(), but the not migrated pages are left in the from page list without being added back to LRU lists. Fix it by adding a new nr_split counter for large folio splits and adding it to nr_failed in migrate_page_sync() after migrate_pages_batch() is done. Link: https://lkml.kernel.org/r/20231017163129.2025214-1-zi.yan@sent.com Fixes: 2ef7dbb26990 ("migrate_pages: try migrate in batch asynchronously firstly") Signed-off-by: Zi Yan Acked-by: Huang Ying Reviewed-by: Baolin Wang Cc: David Hildenbrand Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Huacai Chen --- This patch has a Fixes tag and should be backported to 6.6, I don't know why hasn't bakported. mm/migrate.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 1004b1def1c2..4ed470885217 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1504,6 +1504,7 @@ struct migrate_pages_stats { int nr_thp_succeeded; /* THP migrated successfully */ int nr_thp_failed; /* THP failed to be migrated */ int nr_thp_split; /* THP split before migrating */ + int nr_split; /* Large folio (include THP) split before migrating */ }; /* @@ -1623,6 +1624,7 @@ static int migrate_pages_batch(struct list_head *from, int nr_retry_pages = 0; int pass = 0; bool is_thp = false; + bool is_large = false; struct folio *folio, *folio2, *dst = NULL, *dst2; int rc, rc_saved = 0, nr_pages; LIST_HEAD(unmap_folios); @@ -1638,7 +1640,8 @@ static int migrate_pages_batch(struct list_head *from, nr_retry_pages = 0; list_for_each_entry_safe(folio, folio2, from, lru) { - is_thp = folio_test_large(folio) && folio_test_pmd_mappable(folio); + is_large = folio_test_large(folio); + is_thp = is_large && folio_test_pmd_mappable(folio); nr_pages = folio_nr_pages(folio); cond_resched(); @@ -1658,6 +1661,7 @@ static int migrate_pages_batch(struct list_head *from, stats->nr_thp_failed++; if (!try_split_folio(folio, split_folios)) { stats->nr_thp_split++; + stats->nr_split++; continue; } stats->nr_failed_pages += nr_pages; @@ -1686,11 +1690,12 @@ static int migrate_pages_batch(struct list_head *from, nr_failed++; stats->nr_thp_failed += is_thp; /* Large folio NUMA faulting doesn't split to retry. */ - if (folio_test_large(folio) && !nosplit) { + if (is_large && !nosplit) { int ret = try_split_folio(folio, split_folios); if (!ret) { stats->nr_thp_split += is_thp; + stats->nr_split += is_large; break; } else if (reason == MR_LONGTERM_PIN && ret == -EAGAIN) { @@ -1836,6 +1841,7 @@ static int migrate_pages_sync(struct list_head *from, new_folio_t get_new_folio, stats->nr_succeeded += astats.nr_succeeded; stats->nr_thp_succeeded += astats.nr_thp_succeeded; stats->nr_thp_split += astats.nr_thp_split; + stats->nr_split += astats.nr_split; if (rc < 0) { stats->nr_failed_pages += astats.nr_failed_pages; stats->nr_thp_failed += astats.nr_thp_failed; @@ -1843,7 +1849,11 @@ static int migrate_pages_sync(struct list_head *from, new_folio_t get_new_folio, return rc; } stats->nr_thp_failed += astats.nr_thp_split; - nr_failed += astats.nr_thp_split; + /* + * Do not count rc, as pages will be retried below. + * Count nr_split only, since it includes nr_thp_split. + */ + nr_failed += astats.nr_split; /* * Fall back to migrate all failed folios one by one synchronously. All * failed folios except split THPs will be retried, so their failure -- 2.47.1