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Wed, 06 Oct 2021 13:15:13 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyABKk/9Kv5nK/n8wDOgt5wHwzEBYKofFmU30gYxiWgdXVd9pFaNq3S6Bq1e4aIY9E2QEcyUw== X-Received: by 2002:a37:48c:: with SMTP id 134mr100776qke.233.1633551313175; Wed, 06 Oct 2021 13:15:13 -0700 (PDT) Received: from t490s ([2607:fea8:56a2:9100::bed8]) by smtp.gmail.com with ESMTPSA id b19sm1531437qto.46.2021.10.06.13.15.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Oct 2021 13:15:12 -0700 (PDT) Date: Wed, 6 Oct 2021 16:15:11 -0400 From: Peter Xu To: Yang Shi Cc: naoya.horiguchi@nec.com, hughd@google.com, kirill.shutemov@linux.intel.com, willy@infradead.org, osalvador@suse.de, akpm@linux-foundation.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [v3 PATCH 2/5] mm: filemap: check if THP has hwpoisoned subpage for PMD page fault Message-ID: References: <20210930215311.240774-1-shy828301@gmail.com> <20210930215311.240774-3-shy828301@gmail.com> MIME-Version: 1.0 In-Reply-To: <20210930215311.240774-3-shy828301@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Queue-Id: 516B6D0013E9 X-Stat-Signature: j6eycxidi9ig7q5mfjyrkccfsp1jf7is Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Jp8D0Sqs; spf=none (imf20.hostedemail.com: domain of peterx@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=peterx@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam06 X-HE-Tag: 1633551315-663756 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: On Thu, Sep 30, 2021 at 02:53:08PM -0700, Yang Shi wrote: > @@ -1148,8 +1148,12 @@ static int __get_hwpoison_page(struct page *page) > return -EBUSY; > > if (get_page_unless_zero(head)) { > - if (head == compound_head(page)) > + if (head == compound_head(page)) { > + if (PageTransHuge(head)) > + SetPageHasHWPoisoned(head); > + > return 1; > + } > > pr_info("Memory failure: %#lx cannot catch tail\n", > page_to_pfn(page)); Sorry for the late comments. I'm wondering whether it's ideal to set this bit here, as get_hwpoison_page() sounds like a pure helper to get a refcount out of a sane hwpoisoned page. I'm afraid there can be side effect that we set this without being noticed, so I'm also wondering we should keep it in memory_failure(). Quotting comments for get_hwpoison_page(): * get_hwpoison_page() takes a page refcount of an error page to handle memory * error on it, after checking that the error page is in a well-defined state * (defined as a page-type we can successfully handle the memor error on it, * such as LRU page and hugetlb page). For example, I see that both unpoison_memory() and soft_offline_page() will call it too, does it mean that we'll also set the bits e.g. even when we want to inject an unpoison event too? Thanks, -- Peter Xu