From: Matthew Wilcox <willy@infradead.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Seema Pandit <seema.pandit@intel.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
stable <stable@vger.kernel.org>,
Robert Barror <robert.barror@intel.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Jan Kara <jack@suse.cz>
Subject: Re: [PATCH] filesystem-dax: Disable PMD support
Date: Fri, 28 Jun 2019 09:54:17 -0700 [thread overview]
Message-ID: <20190628165417.GD4286@bombadil.infradead.org> (raw)
In-Reply-To: <CAPcyv4jeRwhYWnGw9RrfDA54RRa9LK4JPuF3zQ-av=HdRqCTJw@mail.gmail.com>
On Fri, Jun 28, 2019 at 09:39:01AM -0700, Dan Williams wrote:
> On Fri, Jun 28, 2019 at 9:37 AM Matthew Wilcox <willy@infradead.org> wrote:
> > That was the conclusion I came to; that one thread holding the mmap sem
> > for read isn't being woken up when it should be. Just need to find it ...
> > obviously it's something to do with the PMD entries.
>
> Can you explain to me one more time, yes I'm slow on the uptake on
> this, the difference between xas_load() and xas_find_conflict() and
> why it's ok for dax_lock_page() to use xas_load() while
> grab_mapping_entry() uses xas_find_conflict()?
When used with a non-zero 'order', xas_find_conflict() will return
an entry whereas xas_load() might return a pointer to a node.
dax_lock_page() always uses a zero order, so they would always do the
same thing (xas_find_conflict() would be less efficient).
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WARNING: multiple messages have this Message-ID (diff)
From: Matthew Wilcox <willy@infradead.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm <linux-nvdimm@lists.01.org>, Jan Kara <jack@suse.cz>,
stable <stable@vger.kernel.org>,
Robert Barror <robert.barror@intel.com>,
Seema Pandit <seema.pandit@intel.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] filesystem-dax: Disable PMD support
Date: Fri, 28 Jun 2019 09:54:17 -0700 [thread overview]
Message-ID: <20190628165417.GD4286@bombadil.infradead.org> (raw)
In-Reply-To: <CAPcyv4jeRwhYWnGw9RrfDA54RRa9LK4JPuF3zQ-av=HdRqCTJw@mail.gmail.com>
On Fri, Jun 28, 2019 at 09:39:01AM -0700, Dan Williams wrote:
> On Fri, Jun 28, 2019 at 9:37 AM Matthew Wilcox <willy@infradead.org> wrote:
> > That was the conclusion I came to; that one thread holding the mmap sem
> > for read isn't being woken up when it should be. Just need to find it ...
> > obviously it's something to do with the PMD entries.
>
> Can you explain to me one more time, yes I'm slow on the uptake on
> this, the difference between xas_load() and xas_find_conflict() and
> why it's ok for dax_lock_page() to use xas_load() while
> grab_mapping_entry() uses xas_find_conflict()?
When used with a non-zero 'order', xas_find_conflict() will return
an entry whereas xas_load() might return a pointer to a node.
dax_lock_page() always uses a zero order, so they would always do the
same thing (xas_find_conflict() would be less efficient).
next prev parent reply other threads:[~2019-06-28 16:54 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-27 0:15 [PATCH] filesystem-dax: Disable PMD support Dan Williams
2019-06-27 0:15 ` Dan Williams
2019-06-27 12:34 ` Matthew Wilcox
2019-06-27 12:34 ` Matthew Wilcox
2019-06-27 16:06 ` Dan Williams
2019-06-27 16:06 ` Dan Williams
2019-06-27 18:29 ` Dan Williams
2019-06-27 18:29 ` Dan Williams
2019-06-27 18:58 ` Dan Williams
2019-06-27 18:58 ` Dan Williams
2019-06-27 19:09 ` Dan Williams
2019-06-27 19:09 ` Dan Williams
2019-06-27 19:59 ` Matthew Wilcox
2019-06-27 19:59 ` Matthew Wilcox
2019-06-28 2:39 ` Dan Williams
2019-06-28 2:39 ` Dan Williams
2019-06-28 16:37 ` Matthew Wilcox
2019-06-28 16:37 ` Matthew Wilcox
2019-06-28 16:39 ` Dan Williams
2019-06-28 16:39 ` Dan Williams
2019-06-28 16:54 ` Matthew Wilcox [this message]
2019-06-28 16:54 ` Matthew Wilcox
2019-06-29 16:03 ` Matthew Wilcox
2019-06-29 16:03 ` Matthew Wilcox
2019-06-30 7:27 ` Dan Williams
2019-06-30 7:27 ` Dan Williams
2019-06-30 8:01 ` Dan Williams
2019-06-30 8:01 ` Dan Williams
2019-06-30 15:23 ` Matthew Wilcox
2019-06-30 15:23 ` Matthew Wilcox
2019-06-30 21:37 ` Dan Williams
2019-06-30 21:37 ` Dan Williams
2019-07-02 3:34 ` Matthew Wilcox
2019-07-02 3:34 ` Matthew Wilcox
2019-07-02 15:37 ` Dan Williams
2019-07-02 15:37 ` Dan Williams
2019-07-03 0:22 ` Boaz Harrosh
2019-07-03 0:22 ` Boaz Harrosh
2019-07-03 0:42 ` Dan Williams
2019-07-03 0:42 ` Dan Williams
2019-07-03 1:39 ` Boaz Harrosh
2019-07-03 1:39 ` Boaz Harrosh
2019-07-01 12:11 ` Jan Kara
2019-07-01 12:11 ` Jan Kara
2019-07-03 15:47 ` Matthew Wilcox
2019-07-03 15:47 ` Matthew Wilcox
2019-07-04 16:40 ` Jan Kara
2019-07-04 16:40 ` Jan Kara
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