From: Nigel Cunningham <nigel@tuxonice.net>
To: Mark Lord <kernel@teksavvy.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
pm list <linux-pm@lists.linux-foundation.org>
Subject: Re: 2.6.35 Regression: Ages spent discarding blocks that weren't used!
Date: Thu, 05 Aug 2010 07:22:30 +1000 [thread overview]
Message-ID: <4C59DA16.4020500@tuxonice.net> (raw)
In-Reply-To: <4C5960B0.7020003@teksavvy.com>
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
next prev parent reply other threads:[~2010-08-04 21:22 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-04 1:40 2.6.35 Regression: Ages spent discarding blocks that weren't used! Nigel Cunningham
2010-08-04 8:59 ` Stefan Richter
2010-08-04 9:16 ` Nigel Cunningham
2010-08-04 9:16 ` Nigel Cunningham
2010-08-04 8:59 ` Stefan Richter
2010-08-04 12:44 ` Mark Lord
2010-08-04 12:44 ` Mark Lord
2010-08-04 18:02 ` Martin K. Petersen
2010-08-04 18:02 ` Martin K. Petersen
2010-08-04 21:22 ` Nigel Cunningham
2010-08-04 21:22 ` Nigel Cunningham [this message]
2010-08-05 3:58 ` Hugh Dickins
2010-08-05 6:28 ` Nigel Cunningham
2010-08-06 1:15 ` Hugh Dickins
2010-08-06 1:15 ` Hugh Dickins
2010-08-06 4:40 ` Nigel Cunningham
2010-08-06 22:07 ` Hugh Dickins
2010-08-06 22:07 ` Hugh Dickins
2010-08-07 22:47 ` Nigel Cunningham
2010-08-07 22:47 ` Nigel Cunningham
2010-08-13 11:54 ` Christoph Hellwig
2010-08-13 18:15 ` Hugh Dickins
2010-08-14 11:43 ` Christoph Hellwig
2010-08-14 11:43 ` Christoph Hellwig
2010-08-13 18:15 ` Hugh Dickins
2010-08-13 11:54 ` Christoph Hellwig
2010-08-06 4:40 ` Nigel Cunningham
2010-08-05 6:28 ` Nigel Cunningham
2010-08-05 3:58 ` Hugh Dickins
2010-08-04 1:40 Nigel Cunningham
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