Re: speeding up swapoff

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, 29 Aug 2007 09:29:32 -0400
Daniel Drake <[email protected]> wrote:


Hi,

> I've spent some time trying to understand why swapoff is such a slow
> operation.
> 
> My experiments show that when there is not much free physical memory,
> swapoff moves pages out of swap at a rate of approximately 5mb/sec.

sounds like about disk speed (at random-seek IO pattern)


> I'm happy to spend a few more hours looking into implementing this but
> would greatly appreciate any advice from those in-the-know on if my
> ideas are broken to start with...

before you go there... is this a "real life" problem? Or just a
mostly-artificial corner case? (the answer to that obviously is
relevant for the 'should we really care' question)

Another question, if this is during system shutdown, maybe that's a
valid case for flushing most of the pagecache first (from userspace)
since most of what's there won't be used again anyway. If that's enough
to make this go faster...

A third question, have you investigated what happens if a process gets
killed that has pages in swap; as long as we don't page those in but
just forget about them, that would solve the shutdown problem nicely
(since we kill stuff first anyway there)

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux