Messages in this thread | | | Date | Mon, 10 Apr 2006 12:25:07 +0200 (CEST) | From | Grzegorz Kulewski <> | Subject | Re: Slow swapon for big (12GB) swap |
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On Mon, 10 Apr 2006, Andrew Morton wrote: > Grzegorz Kulewski <kangur@polcom.net> wrote: >> >> I am using big swap here (as a backing for potentially huge tmpfs). And I >> wonder why swapon on such big (like 12GB) swap takes about 7 minutes >> (continuous disk IO). > > It's a bit quicker here: > > vmm:/usr/src/25# mkswap /dev/hda6 > Setting up swapspace version 1, size = 54031826 kB > vmm:/usr/src/25# time swapon /dev/hda6 > swapon /dev/hda6 0.00s user 0.04s system 74% cpu 0.054 total > > >> Is this expected? > > Nope. > >> Why it is like that? > > Are you using a swapfile or a swap partition?
Swap file.
> If it's a swapfile then perhaps the filesystem is being inefficient in its > bmap() function. Which filesystem is it?
Ext3.
The kernel is 2.6.16-rc3-git2-ck1. There is -ck patch in it but I strongly hope that swap prefetch is not *that* buggy to cause such things... I am considering testing vanilla. Con CC'd.
The system is Athlon XP 2000MHz with 1GB of RAM and Samsung 80GB IDE hard drive.
The second run of swapon is very fast (like 2 seconds). So it looks like it has cached something in RAM?...
Thanks,
Grzegorz Kulewski
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