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[175.177.40.153]) by smtp.gmail.com with ESMTPSA id z14sm10952986pfn.11.2021.06.13.19.12.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Jun 2021 19:12:30 -0700 (PDT) From: Naoya Horiguchi To: linux-mm@kvack.org Cc: Andrew Morton , David Hildenbrand , Oscar Salvador , Michal Hocko , Ding Hui , Tony Luck , "Aneesh Kumar K.V" , Naoya Horiguchi , linux-kernel@vger.kernel.org Subject: [PATCH v1 2/6] mm/hwpoison: remove race consideration Date: Mon, 14 Jun 2021 11:12:08 +0900 Message-Id: <20210614021212.223326-3-nao.horiguchi@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210614021212.223326-1-nao.horiguchi@gmail.com> References: <20210614021212.223326-1-nao.horiguchi@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Naoya Horiguchi Now memory_failure() and unpoison_memory() are protected by mf_mutex, so no need to explicitly check races between them. So remove them. Signed-off-by: Naoya Horiguchi --- mm/memory-failure.c | 37 ------------------------------------- 1 file changed, 37 deletions(-) diff --git v5.13-rc5/mm/memory-failure.c v5.13-rc5_patched/mm/memory-failure.c index 280eb6d6dd15..e7910386fc9c 100644 --- v5.13-rc5/mm/memory-failure.c +++ v5.13-rc5_patched/mm/memory-failure.c @@ -1461,14 +1461,6 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) lock_page(head); page_flags = head->flags; - if (!PageHWPoison(head)) { - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); - num_poisoned_pages_dec(); - unlock_page(head); - put_page(head); - return 0; - } - /* * TODO: hwpoison for pud-sized hugetlb doesn't work right now, so * simply disable it. In order to make it work properly, we need @@ -1730,16 +1722,6 @@ int memory_failure(unsigned long pfn, int flags) */ page_flags = p->flags; - /* - * unpoison always clear PG_hwpoison inside page lock - */ - if (!PageHWPoison(p)) { - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); - num_poisoned_pages_dec(); - unlock_page(p); - put_page(p); - goto unlock_mutex; - } if (hwpoison_filter(p)) { if (TestClearPageHWPoison(p)) num_poisoned_pages_dec(); @@ -1956,17 +1938,6 @@ int unpoison_memory(unsigned long pfn) goto unlock_mutex; } - /* - * unpoison_memory() can encounter thp only when the thp is being - * worked by memory_failure() and the page lock is not held yet. - * In such case, we yield to memory_failure() and make unpoison fail. - */ - if (!PageHuge(page) && PageTransHuge(page)) { - unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n", - pfn, &unpoison_rs); - goto unlock_mutex; - } - if (!get_hwpoison_page(p, flags)) { if (TestClearPageHWPoison(p)) num_poisoned_pages_dec(); @@ -1975,20 +1946,12 @@ int unpoison_memory(unsigned long pfn) goto unlock_mutex; } - lock_page(page); - /* - * This test is racy because PG_hwpoison is set outside of page lock. - * That's acceptable because that won't trigger kernel panic. Instead, - * the PG_hwpoison page will be caught and isolated on the entrance to - * the free buddy page pool. - */ if (TestClearPageHWPoison(page)) { unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n", pfn, &unpoison_rs); num_poisoned_pages_dec(); freeit = 1; } - unlock_page(page); put_page(page); if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) -- 2.25.1