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From: Dan Williams <dan.j.williams@intel.com>
To: "ruansy.fnst@fujitsu.com" <ruansy.fnst@fujitsu.com>
Cc: Jane Chu <jane.chu@oracle.com>,
	 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	 "linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
	 "nvdimm@lists.linux.dev" <nvdimm@lists.linux.dev>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	 "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"dm-devel@redhat.com" <dm-devel@redhat.com>,
	 "djwong@kernel.org" <djwong@kernel.org>,
	"david@fromorbit.com" <david@fromorbit.com>,
	"hch@lst.de" <hch@lst.de>,  "agk@redhat.com" <agk@redhat.com>,
	"snitzer@redhat.com" <snitzer@redhat.com>
Subject: Re: [PATCH RESEND v6 1/9] pagemap: Introduce ->memory_failure()
Date: Wed, 18 Aug 2021 10:10:51 -0700	[thread overview]
Message-ID: <CAPcyv4gS=sYbC3gzMN0uQ5SAhDJ8CAC81tz7AtMueqLfuzGDOw@mail.gmail.com> (raw)
In-Reply-To: <OSBPR01MB2920AD0C7FD02E238D0C387AF4FF9@OSBPR01MB2920.jpnprd01.prod.outlook.com>

On Wed, Aug 18, 2021 at 12:52 AM ruansy.fnst@fujitsu.com
<ruansy.fnst@fujitsu.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Jane Chu <jane.chu@oracle.com>
> > Subject: Re: [PATCH RESEND v6 1/9] pagemap: Introduce ->memory_failure()
> >
> >
> > On 8/17/2021 10:43 PM, Jane Chu wrote:
> > > More information -
> > >
> > > On 8/16/2021 10:20 AM, Jane Chu wrote:
> > >> Hi, ShiYang,
> > >>
> > >> So I applied the v6 patch series to my 5.14-rc3 as it's what you
> > >> indicated is what v6 was based at, and injected a hardware poison.
> > >>
> > >> I'm seeing the same problem that was reported a while ago after the
> > >> poison was consumed - in the SIGBUS payload, the si_addr is missing:
> > >>
> > >> ** SIGBUS(7): canjmp=1, whichstep=0, **
> > >> ** si_addr(0x(nil)), si_lsb(0xC), si_code(0x4, BUS_MCEERR_AR) **
> > >>
> > >> The si_addr ought to be 0x7f6568000000 - the vaddr of the first page
> > >> in this case.
> > >
> > > The failure came from here :
> > >
> > > [PATCH RESEND v6 6/9] xfs: Implement ->notify_failure() for XFS
> > >
> > > +static int
> > > +xfs_dax_notify_failure(
> > > ...
> > > +    if (!xfs_sb_version_hasrmapbt(&mp->m_sb)) {
> > > +        xfs_warn(mp, "notify_failure() needs rmapbt enabled!");
> > > +        return -EOPNOTSUPP;
> > > +    }
> > >
> > > I am not familiar with XFS, but I have a few questions I hope to get
> > > answers -
> > >
> > > 1) What does it take and cost to make
> > >     xfs_sb_version_hasrmapbt(&mp->m_sb) to return true?
>
> Enable rmpabt feature when making xfs filesystem
>    `mkfs.xfs -m rmapbt=1 /path/to/device`
> BTW, reflink is enabled by default.
>
> > >
> > > 2) For a running environment that fails the above check, is it
> > >     okay to leave the poison handle in limbo and why?
> It will fall back to the old handler.  I think you have already known it.
>
> > >
> > > 3) If the above regression is not acceptable, any potential remedy?
> >
> > How about moving the check to prior to the notifier registration?
> > And register only if the check is passed?  This seems better than an
> > alternative which is to fall back to the legacy memory_failure handling in case
> > the filesystem returns -EOPNOTSUPP.
>
> Sounds like a nice solution.  I think I can add an is_notify_supported() interface in dax_holder_ops and check it when register dax_holder.

Shouldn't the fs avoid registering a memory failure handler if it is
not prepared to take over? For example, shouldn't this case behave
identically to ext4 that will not even register a callback?


  reply	other threads:[~2021-08-18 17:11 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 10:01 [PATCH RESEND v6 0/9] fsdax: introduce fs query to support reflink Shiyang Ruan
2021-07-30 10:01 ` [PATCH RESEND v6 1/9] pagemap: Introduce ->memory_failure() Shiyang Ruan
2021-08-06  1:17   ` Jane Chu
2021-08-16 17:20     ` Jane Chu
2021-08-17  1:44       ` ruansy.fnst
2021-08-18  5:43       ` Jane Chu
2021-08-18  6:08         ` Jane Chu
2021-08-18  7:52           ` ruansy.fnst
2021-08-18 17:10             ` Dan Williams [this message]
2021-08-23 13:21               ` hch
2021-08-18 15:52           ` Darrick J. Wong
2021-08-19  7:18           ` Jane Chu
2021-08-19  8:11             ` Jane Chu
2021-08-19  9:10               ` ruansy.fnst
2021-08-19 20:50                 ` Jane Chu
2021-08-20 16:07   ` Dan Williams
2021-07-30 10:01 ` [PATCH RESEND v6 2/9] dax: Introduce holder for dax_device Shiyang Ruan
2021-08-06  1:02   ` Jane Chu
2021-08-17  1:45     ` ruansy.fnst
2021-08-20 16:06   ` Dan Williams
2021-08-20 20:19   ` Dan Williams
2021-07-30 10:01 ` [PATCH RESEND v6 3/9] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
2021-08-06  1:00   ` Jane Chu
2021-08-20 16:54     ` Dan Williams
2021-07-30 10:01 ` [PATCH RESEND v6 4/9] pmem,mm: Implement ->memory_failure in pmem driver Shiyang Ruan
2021-08-20 20:51   ` Dan Williams
2021-07-30 10:01 ` [PATCH RESEND v6 5/9] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
2021-08-06  0:59   ` Jane Chu
2021-08-20 22:40   ` Dan Williams
2021-07-30 10:01 ` [PATCH RESEND v6 6/9] xfs: Implement ->notify_failure() for XFS Shiyang Ruan
2021-08-06  0:50   ` Jane Chu
2021-08-20 22:56     ` Dan Williams
2021-08-20 22:59   ` Dan Williams
2021-07-30 10:01 ` [PATCH RESEND v6 7/9] dm: Introduce ->rmap() to find bdev offset Shiyang Ruan
2021-08-20 23:46   ` Dan Williams
2021-07-30 10:01 ` [PATCH RESEND v6 8/9] md: Implement dax_holder_operations Shiyang Ruan
2021-08-06  0:48   ` Jane Chu
2021-08-17  1:59     ` ruansy.fnst
2021-07-30 10:01 ` [PATCH RESEND v6 9/9] fsdax: add exception for reflinked files Shiyang Ruan
2021-08-06  0:46   ` Jane Chu

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