From: Peter Kruse <pk@q-leap.de>
To: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>,
eric.dumazet@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: I have a blaze of 353 page allocation failures, all alike
Date: Wed, 13 Apr 2011 09:13:46 +0200 [thread overview]
Message-ID: <4DA54D2A.3050206@q-leap.de> (raw)
In-Reply-To: <alpine.DEB.2.00.1104121830030.14956@chino.kir.corp.google.com>
Hello,
thanks for your replies, I appreciate that.
On 04/13/2011 03:34 AM, David Rientjes wrote:
> On Tue, 12 Apr 2011, Christoph Lameter wrote:
>
>> The problem maybe that you have lots and lots of SCSI devices which
>> consume ZONE_DMA memory for their control structures. I guess that is
>> oversubscribing the 16M zone.
but there are only two devices:
# fdisk -l
Disk /dev/sda: 249.8 GB, 249865175040 bytes
255 heads, 63 sectors/track, 30377 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x4ac39024
Device Boot Start End Blocks Id System
/dev/sda1 1 13 104422 83 Linux
/dev/sda2 14 30377 243898830 8e Linux LVM
WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk
doesn't support GPT. Use GNU Parted.
Disk /dev/sdb: 37946.0 GB, 37946025574400 bytes
255 heads, 63 sectors/track, 4613341 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/sdb doesn't contain a valid partition table
> You can try to get more memory reserves specifically for lowmem in
> ZONE_DMA by changing /proc/sys/vm/lowmem_reserve_ratio. The values are
> ratios, so lowering the numbers will yield larger amounts of memory
> reserves in ZONE_DMA for GFP_DMA allocations. Try lowering the non-zero
> entries to 1 to reserve the entire zone for lowmem, assuming your system
> has enough RAM for everything else you're running.
this server has 48GB - that should be enough.
> This will verify if ZONE_DMA is being depleted from the larger number of
> SCSI devices. If you don't get any additional page allocation failures,
> then check how much memory in ZONE_DMA is used at peak and that would be a
> sane reserve ratio to use next time you restart the system.
Could that still be a problem if there are only two scsi devices?
Regards,
Peter
next prev parent reply other threads:[~2011-04-13 7:13 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-10 15:03 I have a blaze of 353 page allocation failures, all alike Peter Kruse
2011-02-14 16:49 ` Christoph Lameter
2011-02-15 7:44 ` Peter Kruse
2011-02-15 17:30 ` Christoph Lameter
2011-02-16 12:22 ` Peter Kruse
2011-02-16 15:59 ` Christoph Lameter
2011-02-16 16:03 ` Peter Kruse
2011-02-16 16:14 ` Christoph Lameter
2011-02-17 7:31 ` Peter Kruse
2011-02-17 17:03 ` Christoph Lameter
2011-02-18 12:30 ` Peter Kruse
2011-02-24 12:01 ` Peter Kruse
2011-04-12 15:01 ` Peter Kruse
2011-04-12 18:08 ` Christoph Lameter
2011-04-13 1:34 ` David Rientjes
2011-04-13 7:13 ` Peter Kruse [this message]
2011-04-13 16:17 ` Christoph Lameter
2011-05-19 11:56 ` Peter Kruse
2011-05-19 16:00 ` Christoph Lameter
2011-05-23 6:34 ` Peter Kruse
[not found] ` <4E09BEA1.1080501@q-leap.de>
[not found] ` <alpine.DEB.2.00.1107051013500.16869@router.home>
2011-07-05 17:20 ` Mel Gorman
2011-07-06 4:16 ` Dave Chinner
2011-07-06 6:50 ` Peter Kruse
2011-07-06 14:31 ` Christoph Lameter
2011-07-06 15:15 ` Peter Kruse
2011-07-06 15:30 ` Christoph Lameter
2011-11-24 10:53 ` Peter Kruse
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