Re: kswapd continuously active

From: Jan Engelhardt
Date: Fri Feb 05 2010 - 08:09:16 EST



On Friday 2010-02-05 14:00, Jens Axboe wrote:
>> >January 25 Feb-05
>> >MemTotal: 8166752 kB 8166752
>> >MemFree: 3243552 kB 3781776
>> >Buffers: 207968 kB 4912
>> >Cached: 2728216 kB 2684400
>> >SwapCached: 0 kB 0
>> >Active: 2203136 kB 495624
>> >Inactive: 2152544 kB 3263136
>> >Active(anon): 1167256 kB 488168
>> >Inactive(anon): 252952 kB 583912
>> >Active(file): 1035880 kB 7456
>> >Inactive(file): 1899592 kB 2679224
>> >Unevictable: 0 kB 0
>> >Mlocked: 0 kB 0
>> >SwapTotal: 0 kB 0
>> >SwapFree: 0 kB 0
>> >Dirty: 141624 kB 2662184
>> >Writeback: 0 kB ..
>>
>> Today this happened again. So I looked at /proc/meminfo to paste today's
>> values next to those from January. That is when I noticed the "Dirty"
>> value - and thus I ran
>>
>> watch -d -n 1 'grep Dirty /proc/meminfo'
>>
>> What I see is that the dirty amount - a sync is currently running -
>> only decreases with at most 400 KB/sec, often less than that.
>
>I'm guessing the barriers and commits are what is killing your
>performance. What happens with barrier=0?

The ext4 filesystem is already mounted with barrier=0. If there
is any block-level barriers I also can turn off, what would be
the command?


thanks,
Jan
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