From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753876AbcALXuE (ORCPT ); Tue, 12 Jan 2016 18:50:04 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:43048 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752961AbcALXuA (ORCPT ); Tue, 12 Jan 2016 18:50:00 -0500 Date: Tue, 12 Jan 2016 15:49:59 -0800 From: Andrew Morton To: Naoya Horiguchi Cc: Andi Kleen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Naoya Horiguchi , "Kirill A. Shutemov" Subject: Re: [PATCH v2 2/2] mm: soft-offline: exit with failure for non anonymous thp Message-Id: <20160112154959.009a3944dd094dc2234e2f65@linux-foundation.org> In-Reply-To: <1452568245-10412-3-git-send-email-n-horiguchi@ah.jp.nec.com> References: <20160108123300.843d370916d3248be297d831@linux-foundation.org> <1452568245-10412-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1452568245-10412-3-git-send-email-n-horiguchi@ah.jp.nec.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 12 Jan 2016 12:10:45 +0900 Naoya Horiguchi wrote: > Currently memory_failure() doesn't handle non anonymous thp case, because we > can hardly expect the error handling to be successful, and it can just hit > some corner case which results in BUG_ON or something severe like that. > This is also the case for soft offline code, so let's make it in the same way. > > Orignal code has a MF_COUNT_INCREASED check before put_hwpoison_page(), but > it's unnecessary because get_any_page() is already called when running on > this code, which takes a refcount of the target page regardress of the flag. > So this patch also removes it. > > ... > > --- next-20160111/mm/memory-failure.c > +++ next-20160111_patched/mm/memory-failure.c > @@ -1691,16 +1691,16 @@ static int soft_offline_in_use_page(struct page *page, int flags) > > if (!PageHuge(page) && PageTransHuge(hpage)) { > lock_page(hpage); > - ret = split_huge_page(hpage); > - unlock_page(hpage); > - if (unlikely(ret || PageTransCompound(page) || > - !PageAnon(page))) { > - pr_info("soft offline: %#lx: failed to split THP\n", > - page_to_pfn(page)); > - if (flags & MF_COUNT_INCREASED) > - put_hwpoison_page(hpage); > + if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) { > + unlock_page(hpage); > + if (!PageAnon(hpage)) > + pr_info("soft offline: %#lx: non anonymous thp\n", pfn); > + else > + pr_info("soft offline: %#lx: thp split failed\n", pfn); > + put_hwpoison_page(hpage); > return -EBUSY; > } hm, what happened there. mm/memory-failure.c: In function 'soft_offline_in_use_page': mm/memory-failure.c:1697: error: 'pfn' undeclared (first use in this function) mm/memory-failure.c:1697: error: (Each undeclared identifier is reported only once mm/memory-failure.c:1697: error: for each function it appears in.) --- a/mm/memory-failure.c~mm-soft-offline-exit-with-failure-for-non-anonymous-thp-fix +++ a/mm/memory-failure.c @@ -1694,9 +1694,9 @@ static int soft_offline_in_use_page(stru if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) { unlock_page(hpage); if (!PageAnon(hpage)) - pr_info("soft offline: %#lx: non anonymous thp\n", pfn); + pr_info("soft offline: %#lx: non anonymous thp\n", page_to_pfn(page)); else - pr_info("soft offline: %#lx: thp split failed\n", pfn); + pr_info("soft offline: %#lx: thp split failed\n", page_to_pfn(page)); put_hwpoison_page(hpage); return -EBUSY; } _