From: Dave Chinner <david@fromorbit.com>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [PATCH] gfs2: use __vmalloc GFP_NOFS for fs-related allocations.
Date: Thu, 5 Feb 2015 22:45:00 +1100 [thread overview]
Message-ID: <20150205114459.GI12722@dastard> (raw)
In-Reply-To: <BD2045CE-45AD-4D79-8C8D-C854D112DCC5@linuxhacker.ru>
On Wed, Feb 04, 2015 at 02:13:29AM -0500, Oleg Drokin wrote:
> Hello!
>
> On Feb 3, 2015, at 5:33 PM, Dave Chinner wrote:
> >> I also wonder if vmalloc is still very slow? That was the case some
> >> time ago when I noticed a problem in directory access times in gfs2,
> >> which made us change to use kmalloc with a vmalloc fallback in the
> >> first place,
> > Another of the "myths" about vmalloc. The speed and scalability of
> > vmap/vmalloc is a long solved problem - Nick Piggin fixed the worst
> > of those problems 5-6 years ago - see the rewrite from 2008 that
> > started with commit db64fe0 ("mm: rewrite vmap layer")....
>
> This actually might be less true than one would hope. At least somewhat
> recent studies by LLNL (https://jira.hpdd.intel.com/browse/LU-4008)
> show that there's huge contention on vmlist_lock, so if you have vmalloc
vmlist_lock and the list it protected went away in 3.10.
Cheers,
Dave.
--
Dave Chinner
david at fromorbit.com
WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Oleg Drokin <green@linuxhacker.ru>
Cc: Steven Whitehouse <swhiteho@redhat.com>,
cluster-devel@redhat.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH] gfs2: use __vmalloc GFP_NOFS for fs-related allocations.
Date: Thu, 5 Feb 2015 22:45:00 +1100 [thread overview]
Message-ID: <20150205114459.GI12722@dastard> (raw)
In-Reply-To: <BD2045CE-45AD-4D79-8C8D-C854D112DCC5@linuxhacker.ru>
On Wed, Feb 04, 2015 at 02:13:29AM -0500, Oleg Drokin wrote:
> Hello!
>
> On Feb 3, 2015, at 5:33 PM, Dave Chinner wrote:
> >> I also wonder if vmalloc is still very slow? That was the case some
> >> time ago when I noticed a problem in directory access times in gfs2,
> >> which made us change to use kmalloc with a vmalloc fallback in the
> >> first place,
> > Another of the "myths" about vmalloc. The speed and scalability of
> > vmap/vmalloc is a long solved problem - Nick Piggin fixed the worst
> > of those problems 5-6 years ago - see the rewrite from 2008 that
> > started with commit db64fe0 ("mm: rewrite vmap layer")....
>
> This actually might be less true than one would hope. At least somewhat
> recent studies by LLNL (https://jira.hpdd.intel.com/browse/LU-4008)
> show that there's huge contention on vmlist_lock, so if you have vmalloc
vmlist_lock and the list it protected went away in 3.10.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
--
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WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Oleg Drokin <green@linuxhacker.ru>
Cc: Steven Whitehouse <swhiteho@redhat.com>,
cluster-devel@redhat.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH] gfs2: use __vmalloc GFP_NOFS for fs-related allocations.
Date: Thu, 5 Feb 2015 22:45:00 +1100 [thread overview]
Message-ID: <20150205114459.GI12722@dastard> (raw)
In-Reply-To: <BD2045CE-45AD-4D79-8C8D-C854D112DCC5@linuxhacker.ru>
On Wed, Feb 04, 2015 at 02:13:29AM -0500, Oleg Drokin wrote:
> Hello!
>
> On Feb 3, 2015, at 5:33 PM, Dave Chinner wrote:
> >> I also wonder if vmalloc is still very slow? That was the case some
> >> time ago when I noticed a problem in directory access times in gfs2,
> >> which made us change to use kmalloc with a vmalloc fallback in the
> >> first place,
> > Another of the "myths" about vmalloc. The speed and scalability of
> > vmap/vmalloc is a long solved problem - Nick Piggin fixed the worst
> > of those problems 5-6 years ago - see the rewrite from 2008 that
> > started with commit db64fe0 ("mm: rewrite vmap layer")....
>
> This actually might be less true than one would hope. At least somewhat
> recent studies by LLNL (https://jira.hpdd.intel.com/browse/LU-4008)
> show that there's huge contention on vmlist_lock, so if you have vmalloc
vmlist_lock and the list it protected went away in 3.10.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2015-02-05 11:45 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-02 3:59 [Cluster-devel] [PATCH] gfs2: use __vmalloc GFP_NOFS for fs-related allocations green
2015-02-02 3:59 ` green
2015-02-02 5:37 ` [Cluster-devel] " Dave Chinner
2015-02-02 5:37 ` Dave Chinner
2015-02-02 6:57 ` [Cluster-devel] " Oleg Drokin
2015-02-02 6:57 ` Oleg Drokin
2015-02-02 6:57 ` Oleg Drokin
2015-02-02 8:11 ` [Cluster-devel] " Dave Chinner
2015-02-02 8:11 ` Dave Chinner
2015-02-02 8:11 ` Dave Chinner
2015-02-02 10:30 ` [Cluster-devel] " Steven Whitehouse
2015-02-02 10:30 ` Steven Whitehouse
2015-02-02 10:30 ` Steven Whitehouse
2015-02-03 22:33 ` [Cluster-devel] " Dave Chinner
2015-02-03 22:33 ` Dave Chinner
2015-02-03 22:33 ` Dave Chinner
2015-02-04 7:13 ` [Cluster-devel] " Oleg Drokin
2015-02-04 7:13 ` Oleg Drokin
2015-02-04 7:13 ` Oleg Drokin
2015-02-04 9:49 ` [Cluster-devel] " Steven Whitehouse
2015-02-04 9:49 ` Steven Whitehouse
2015-02-04 9:49 ` Steven Whitehouse
2015-02-05 20:11 ` [Cluster-devel] " Dave Chinner
2015-02-05 20:11 ` Dave Chinner
2015-02-05 20:11 ` Dave Chinner
2015-02-05 11:45 ` Dave Chinner [this message]
2015-02-05 11:45 ` Dave Chinner
2015-02-05 11:45 ` Dave Chinner
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