From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933739AbcA1Fu7 (ORCPT ); Thu, 28 Jan 2016 00:50:59 -0500 Received: from TYO202.gate.nec.co.jp ([210.143.35.52]:49741 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932490AbcA1Fun convert rfc822-to-8bit (ORCPT ); Thu, 28 Jan 2016 00:50:43 -0500 From: Naoya Horiguchi To: Vlastimil Babka CC: Andrew Morton , Chen Gong , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "Naoya Horiguchi" , Linux API , "linux-man@vger.kernel.org" , Michael Kerrisk Subject: Re: [PATCH v1] mm/madvise: pass return code of memory_failure() to userspace Thread-Topic: [PATCH v1] mm/madvise: pass return code of memory_failure() to userspace Thread-Index: AQHRVO7ycrgEO8RsvEaF+M0ct5XjPp8O1Q2AgAEJbAA= Date: Thu, 28 Jan 2016 05:49:11 +0000 Message-ID: <20160128054910.GA5512@hori1.linux.bs1.fc.nec.co.jp> References: <1453451277-20979-1-git-send-email-n-horiguchi@ah.jp.nec.com> <56A8CD2F.5080903@suse.cz> In-Reply-To: <56A8CD2F.5080903@suse.cz> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.128.101.12] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <660470AA4C6CBE4BBBE0AA15FAA87D66@gisp.nec.co.jp> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 27, 2016 at 02:59:11PM +0100, Vlastimil Babka wrote: > [CC += linux-api, linux-man] > > On 01/22/2016 09:27 AM, Naoya Horiguchi wrote: > > Currently the return value of memory_failure() is not passed to userspace, which > > is inconvenient for test programs that want to know the result of error handling. > > So let's return it to the caller as we already do in MADV_SOFT_OFFLINE case. > > > > Signed-off-by: Naoya Horiguchi > > --- > > mm/madvise.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git v4.4-mmotm-2016-01-20-16-10/mm/madvise.c v4.4-mmotm-2016-01-20-16-10_patched/mm/madvise.c > > index f56825b..6a77114 100644 > > --- v4.4-mmotm-2016-01-20-16-10/mm/madvise.c > > +++ v4.4-mmotm-2016-01-20-16-10_patched/mm/madvise.c > > @@ -555,8 +555,9 @@ static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end) > > } > > pr_info("Injecting memory failure for page %#lx at %#lx\n", > > page_to_pfn(p), start); > > - /* Ignore return value for now */ > > - memory_failure(page_to_pfn(p), 0, MF_COUNT_INCREASED); > > + ret = memory_failure(page_to_pfn(p), 0, MF_COUNT_INCREASED); > > + if (ret) > > + return ret; > > Can you explain what madvise can newly return for MADV_HWPOISON in which > situations, for the purposes of updated man page? OK, this patch newly allows madvise(MADV_HWPOISON) to return EBUSY when error handling failed due to 2 major reasons: - the target page is a page type which memory error handler doesn't support (like slab pages, kernel-reserved pages) - the memory error handler failed to isolate the target page (for example, due to failure in unmapping) And for man page purpose, errnos of MADV_SOFT_OFFLINE is not documented either. So let me refer to 2 possible error code from madvise(MADV_SOFT_OFFLINE): - EBUSY: failed to isolate from lru list, - EIO: failed to migrate the target page to another page. Thanks, Naoya Horiguchi From mboxrd@z Thu Jan 1 00:00:00 1970 From: Naoya Horiguchi Subject: Re: [PATCH v1] mm/madvise: pass return code of memory_failure() to userspace Date: Thu, 28 Jan 2016 05:49:11 +0000 Message-ID: <20160128054910.GA5512@hori1.linux.bs1.fc.nec.co.jp> References: <1453451277-20979-1-git-send-email-n-horiguchi@ah.jp.nec.com> <56A8CD2F.5080903@suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <56A8CD2F.5080903@suse.cz> Content-Language: ja-JP Content-ID: <660470AA4C6CBE4BBBE0AA15FAA87D66@gisp.nec.co.jp> Sender: owner-linux-mm@kvack.org To: Vlastimil Babka Cc: Andrew Morton , Chen Gong , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Naoya Horiguchi , Linux API , "linux-man@vger.kernel.org" , Michael Kerrisk List-Id: linux-man@vger.kernel.org On Wed, Jan 27, 2016 at 02:59:11PM +0100, Vlastimil Babka wrote: > [CC +=3D linux-api, linux-man] >=20 > On 01/22/2016 09:27 AM, Naoya Horiguchi wrote: > > Currently the return value of memory_failure() is not passed to userspa= ce, which > > is inconvenient for test programs that want to know the result of error= handling. > > So let's return it to the caller as we already do in MADV_SOFT_OFFLINE = case. > >=20 > > Signed-off-by: Naoya Horiguchi > > --- > > mm/madvise.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > >=20 > > diff --git v4.4-mmotm-2016-01-20-16-10/mm/madvise.c v4.4-mmotm-2016-01-= 20-16-10_patched/mm/madvise.c > > index f56825b..6a77114 100644 > > --- v4.4-mmotm-2016-01-20-16-10/mm/madvise.c > > +++ v4.4-mmotm-2016-01-20-16-10_patched/mm/madvise.c > > @@ -555,8 +555,9 @@ static int madvise_hwpoison(int bhv, unsigned long = start, unsigned long end) > > } > > pr_info("Injecting memory failure for page %#lx at %#lx\n", > > page_to_pfn(p), start); > > - /* Ignore return value for now */ > > - memory_failure(page_to_pfn(p), 0, MF_COUNT_INCREASED); > > + ret =3D memory_failure(page_to_pfn(p), 0, MF_COUNT_INCREASED); > > + if (ret) > > + return ret; >=20 > Can you explain what madvise can newly return for MADV_HWPOISON in which > situations, for the purposes of updated man page? OK, this patch newly allows madvise(MADV_HWPOISON) to return EBUSY when error handling failed due to 2 major reasons: - the target page is a page type which memory error handler doesn't suppor= t (like slab pages, kernel-reserved pages) - the memory error handler failed to isolate the target page (for example, due to failure in unmapping) And for man page purpose, errnos of MADV_SOFT_OFFLINE is not documented eit= her. So let me refer to 2 possible error code from madvise(MADV_SOFT_OFFLINE): - EBUSY: failed to isolate from lru list, - EIO: failed to migrate the target page to another page. Thanks, Naoya Horiguchi= -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org