From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-180.mta0.migadu.com (out-180.mta0.migadu.com [91.218.175.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 997A81E867 for ; Mon, 15 Jan 2024 12:03:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="XMLr/Gyr" Message-ID: <03168121-080f-41e4-a242-02638f5787f7@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1705320181; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=0ku4XsXQqxqtL/FTICwMT++CeuXLKDLkAWaL9IT7UHs=; b=XMLr/GyrtPkV7e9kX240aayMjgfu+hZ4RAC0BD3UMdAsnR5UoeV+/t7OfvMpMiN+SEL4tv Eg7DbbHjNSlgyrXhC4xZvg6fqxayKQ63Vqs2yA7tQ9tqkXZrtDdxNXgvldzv3x8V5AwpyA 0322B8O3yB1KcRQOU4KdyKWmvxGlmWY= Date: Mon, 15 Jan 2024 20:02:51 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v2] fs/hugetlbfs/inode.c: mm/memory-failure.c: fix hugetlbfs hwpoison handling To: Sidhartha Kumar , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: akpm@linux-foundation.org, usama.anjum@collabora.com, jiaqiyan@google.com, willy@infradead.org, linmiaohe@huawei.com, naoya.horiguchi@nec.com, shy828301@gmail.com, jthoughton@google.com, jane.chu@oracle.com, stable@vger.kernel.org References: <20240112180840.367006-1-sidhartha.kumar@oracle.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Muchun Song In-Reply-To: <20240112180840.367006-1-sidhartha.kumar@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2024/1/13 02:08, Sidhartha Kumar wrote: > has_extra_refcount() makes the assumption that the page cache adds a ref > count of 1 and subtracts this in the extra_pins case. Commit a08c7193e4f1 > (mm/filemap: remove hugetlb special casing in filemap.c) modifies > __filemap_add_folio() by calling folio_ref_add(folio, nr); for all cases > (including hugtetlb) where nr is the number of pages in the folio. We > should adjust the number of references coming from the page cache by > subtracing the number of pages rather than 1. > > In hugetlbfs_read_iter(), folio_test_has_hwpoisoned() is testing the wrong > flag as, in the hugetlb case, memory-failure code calls > folio_test_set_hwpoison() to indicate poison. folio_test_hwpoison() is the > correct function to test for that flag. > > After these fixes, the hugetlb hwpoison read selftest passes all cases. > > Fixes: a08c7193e4f1 ("mm/filemap: remove hugetlb special casing in filemap.c") > Closes: https://lore.kernel.org/linux-mm/20230713001833.3778937-1-jiaqiyan@google.com/T/#m8e1469119e5b831bbd05d495f96b842e4a1c5519 > Cc: # 6.7+ > Signed-off-by: Sidhartha Kumar > Reported-by: Muhammad Usama Anjum > --- > > v1 -> v2: > move ref_count adjustment to if(extra_pins) block as that represents > ref counts from the page cache per Miaohe Lin. > > fs/hugetlbfs/inode.c | 2 +- > mm/memory-failure.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c > index 36132c9125f9..3a248e4f7e93 100644 > --- a/fs/hugetlbfs/inode.c > +++ b/fs/hugetlbfs/inode.c > @@ -340,7 +340,7 @@ static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to) > } else { > folio_unlock(folio); > > - if (!folio_test_has_hwpoisoned(folio)) > + if (!folio_test_hwpoison(folio)) > want = nr; > else { > /* > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index d8c853b35dbb..ef7ae73b65bd 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -976,7 +976,7 @@ static bool has_extra_refcount(struct page_state *ps, struct page *p, > int count = page_count(p) - 1; > > if (extra_pins) > - count -= 1; > + count -= folio_nr_pages(page_folio(p)); IIUC, It seems than this also fix shmem of THP, because has_extra_refcount() is called from me_pagecache_clean(), right? > > if (count > 0) { > pr_err("%#lx: %s still referenced by %d users\n",