From: Andrew Morton <akpm@linux-foundation.org>
To: paul.szabo@sydney.edu.au
Cc: dave@linux.vnet.ibm.com, 695182@bugs.debian.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC] Reproducible OOM with partial workaround
Date: Fri, 11 Jan 2013 00:01:19 -0800 [thread overview]
Message-ID: <20130111000119.8e9bdf5d.akpm@linux-foundation.org> (raw)
In-Reply-To: <201301110146.r0B1kF4T032208@como.maths.usyd.edu.au>
On Fri, 11 Jan 2013 12:46:15 +1100 paul.szabo@sydney.edu.au wrote:
> > ... I don't believe 64GB of RAM has _ever_ been booted on a 32-bit
> > kernel without either violating the ABI (3GB/1GB split) or doing
> > something that never got merged upstream ...
>
> Sorry to be so contradictory:
>
> psz@como:~$ uname -a
> Linux como.maths.usyd.edu.au 3.2.32-pk06.10-t01-i386 #1 SMP Sat Jan 5 18:34:25 EST 2013 i686 GNU/Linux
> psz@como:~$ free -l
> total used free shared buffers cached
> Mem: 64446900 4729292 59717608 0 15972 480520
> Low: 375836 304400 71436
> High: 64071064 4424892 59646172
> -/+ buffers/cache: 4232800 60214100
> Swap: 134217724 0 134217724
> psz@como:~$
>
> (though I would not know about violations).
>
> But OK, I take your point that I should move with the times.
Check /proc/slabinfo, see if all your lowmem got eaten up by buffer_heads.
If so, you *may* be able to work around this by setting
/proc/sys/vm/dirty_ratio really low, so the system keeps a minimum
amount of dirty pagecache around. Then, with luck, if we haven't
broken the buffer_heads_over_limit logic it in the past decade (we
probably have), the VM should be able to reclaim those buffer_heads.
Alternatively, use a filesystem which doesn't attach buffer_heads to
dirty pages. xfs or btrfs, perhaps.
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WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: paul.szabo@sydney.edu.au
Cc: dave@linux.vnet.ibm.com, 695182@bugs.debian.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC] Reproducible OOM with partial workaround
Date: Fri, 11 Jan 2013 00:01:19 -0800 [thread overview]
Message-ID: <20130111000119.8e9bdf5d.akpm@linux-foundation.org> (raw)
In-Reply-To: <201301110146.r0B1kF4T032208@como.maths.usyd.edu.au>
On Fri, 11 Jan 2013 12:46:15 +1100 paul.szabo@sydney.edu.au wrote:
> > ... I don't believe 64GB of RAM has _ever_ been booted on a 32-bit
> > kernel without either violating the ABI (3GB/1GB split) or doing
> > something that never got merged upstream ...
>
> Sorry to be so contradictory:
>
> psz@como:~$ uname -a
> Linux como.maths.usyd.edu.au 3.2.32-pk06.10-t01-i386 #1 SMP Sat Jan 5 18:34:25 EST 2013 i686 GNU/Linux
> psz@como:~$ free -l
> total used free shared buffers cached
> Mem: 64446900 4729292 59717608 0 15972 480520
> Low: 375836 304400 71436
> High: 64071064 4424892 59646172
> -/+ buffers/cache: 4232800 60214100
> Swap: 134217724 0 134217724
> psz@como:~$
>
> (though I would not know about violations).
>
> But OK, I take your point that I should move with the times.
Check /proc/slabinfo, see if all your lowmem got eaten up by buffer_heads.
If so, you *may* be able to work around this by setting
/proc/sys/vm/dirty_ratio really low, so the system keeps a minimum
amount of dirty pagecache around. Then, with luck, if we haven't
broken the buffer_heads_over_limit logic it in the past decade (we
probably have), the VM should be able to reclaim those buffer_heads.
Alternatively, use a filesystem which doesn't attach buffer_heads to
dirty pages. xfs or btrfs, perhaps.
next prev parent reply other threads:[~2013-01-11 7:58 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-10 21:58 [RFC] Reproducible OOM with partial workaround paul.szabo
2013-01-10 21:58 ` paul.szabo
2013-01-10 23:12 ` Dave Hansen
2013-01-10 23:12 ` Dave Hansen
2013-01-11 0:46 ` paul.szabo
2013-01-11 0:46 ` paul.szabo
2013-01-11 1:26 ` Dave Hansen
2013-01-11 1:26 ` Dave Hansen
2013-01-11 1:46 ` paul.szabo
2013-01-11 1:46 ` paul.szabo
2013-01-11 8:01 ` Andrew Morton [this message]
2013-01-11 8:01 ` Andrew Morton
2013-01-11 8:30 ` Simon Jeons
2013-01-11 8:30 ` Simon Jeons
2013-01-11 11:51 ` paul.szabo
2013-01-11 11:51 ` paul.szabo
2013-01-11 20:31 ` Andrew Morton
2013-01-11 20:31 ` Andrew Morton
2013-01-12 3:24 ` paul.szabo
2013-01-12 3:24 ` paul.szabo
2013-01-11 16:04 ` Dave Hansen
2013-01-11 16:04 ` Dave Hansen
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