lkml.org 
[lkml]   [2010]   [Aug]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: 2.6.35 Regression: Ages spent discarding blocks that weren't used!
Hi.

On 04/08/10 22:44, Mark Lord wrote:
> Looks to me like more and more things are using the block discard
> functionality, and as predicted it is slowing things down enormously.
>
> The problem is that we still only discard tiny bits (a single range
> still??)
> per TRIM command, rather than batching larger ranges and larger numbers
> of ranges into single TRIM commands.
>
> That's a very poor implementation, especially when things start enabling
> it by default. Eg. the swap code, mke2fs, etc..
>
> Ugh.

I was hoping for a nice quick and simple answer. Since I haven't got
one, I'll try to find time to do a git bisect. I think I'll also look at
the swap code more carefully and see if it's doing the sensible thing. I
can't (at the moment) see the logic behind calling discard when
allocating swap. At freeing time makes much more sense to me.

Regards,

Nigel


\
 
 \ /
  Last update: 2010-08-04 23:25    [W:0.047 / U:0.356 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site