Re: 2.6.1: kernel BUG at mm/swapfile.c:806

From: marcel cotta
Date: Fri Jan 16 2004 - 01:44:12 EST


marcel cotta wrote:
Andrew Morton wrote:

marcel cotta <marcel@xxxxxxxxxxxxx> wrote:

Andrew Morton wrote:

marcel cotta <marcel@xxxxxxxxxxxxx> wrote:


i got this oops after the box swapped like crazy under X for about 5 minutes
while swapping it was nearly unusable (jerky mouse, console switching took 10 seconds)
the extreme performance drop is always reproducible when swapping starts


------------[ cut here ]------------
kernel BUG at mm/swapfile.c:806!



Amazing. Are you using a swapfile, or are you swapping to a block device?





hehe, hasnt been reported for a while eh ;)

i used swapfiles, one static 50mb file and the rest in temp 16MB blocks managed by swapd



What is `swapd'?




the box is still running and i just saw another thing

hades:~# cat /proc/swaps
Filename Type Size Used
Priority
/swap/linux0.swp file 14184 14160 -1
/swap/linux1.swp file 16184 16036
-22
/swap/linux2.swp file 16184 15740
-23
/swap/linux3.swp file 16184 15720
-28
/swap/linux4.swp file 16184 15960
-43
/swap/linux5.swp file 16184 13380
-44
/swap/linux6.swp file 16184 104
-45
/swap/linux7.swp file 16184 0
-46
/swap/linux8.swp file 16184 4
-47


hades:~# free
total used free shared buffers cached
Mem: 188724 184076 4648 0 328 33176
-/+ buffers/cache: 150572 38152
Swap: 127476 90528 36948


have a look at the total swap amount, free reports 127476 but the
total should be 143656
the /swap/linux0.swp file being 2mb smaller is no error
it is caused by setting swapfile size in /etc/swapd.conf to 14184,
while only
this file being in use, and restarting swapd with 16184 as new
swapfile size



another thing as im still playing with this

the swapfiles size is 143656 kb
/proc/swap reports 127476 kb

thats makes a difference of 16180 kb, so 4 kb must be missing since a swapfile is 16184
these are exactly the 4 bytes in the /swap/linux8.swp
i just tried to less it - the process went right into D state :p

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