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Mon, 17 Feb 2025 09:52:48 +0800 (CST) Received: from huawei.com (10.175.124.71) by kwepemg100017.china.huawei.com (7.202.181.58) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 17 Feb 2025 09:52:47 +0800 From: Wupeng Ma To: , , , , , CC: , , Subject: [PATCH v3 2/3] mm: memory-hotplug: check folio ref count first in do_migrate_range Date: Mon, 17 Feb 2025 09:43:28 +0800 Message-ID: <20250217014329.3610326-3-mawupeng1@huawei.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250217014329.3610326-1-mawupeng1@huawei.com> References: <20250217014329.3610326-1-mawupeng1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.71] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemg100017.china.huawei.com (7.202.181.58) X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 2165A14000D X-Stat-Signature: dgo64sjj8wdkxhz6mh9egr4jyccrh3s8 X-Rspam-User: X-HE-Tag: 1739757171-614019 X-HE-Meta: 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 IEzLOPTX p9jxjTMTU1bxdx48TEtPrgkC3y1qaeMXOL0mYCRHTwmMOBIW056JeI94iKbmE4VS1apR4fBghlXWZPbW4/hIcBnP+DCuwA/4fY5LJ0YsbEnhMhoNb/mxdb8UoGslK7xCRqAtW5K+r48BVcsjjd9kevd+1Z9DDkpZ4Ry5HzVM53w+MIQ1vaO4hGhPAFfOmLL/kgwt2OM8qdjhf5t651P6e5zxEv207JP+88xE4863mPqxSKZ0zo71XPwTA9+V9PazFKGPF2qTAR6/69ac= 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: Ma Wupeng If a folio has an increased reference count, folio_try_get() will acquire it, perform necessary operations, and then release it. In the case of a poisoned folio without an elevated reference count (which is unlikely for memory-failure), folio_try_get() will simply bypass it. Therefore, relocate the folio_try_get() function, responsible for checking and acquiring this reference count at first. Signed-off-by: Ma Wupeng Acked-by: David Hildenbrand Acked-by: Miaohe Lin --- mm/memory_hotplug.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 3de661e57e92..3669b3e2d962 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1795,12 +1795,12 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) if (folio_test_large(folio)) pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1; - /* - * HWPoison pages have elevated reference counts so the migration would - * fail on them. It also doesn't make any sense to migrate them in the - * first place. Still try to unmap such a page in case it is still mapped - * (keep the unmap as the catch all safety net). - */ + if (!folio_try_get(folio)) + continue; + + if (unlikely(page_folio(page) != folio)) + goto put_folio; + if (folio_test_hwpoison(folio) || (folio_test_large(folio) && folio_test_has_hwpoisoned(folio))) { if (WARN_ON(folio_test_lru(folio))) @@ -1808,14 +1808,8 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) if (folio_mapped(folio)) unmap_poisoned_folio(folio, pfn, false); - continue; - } - - if (!folio_try_get(folio)) - continue; - - if (unlikely(page_folio(page) != folio)) goto put_folio; + } if (!isolate_folio_to_list(folio, &source)) { if (__ratelimit(&migrate_rs)) {