Revision c4f675cd40d955d539180506c09515c90169b15b authored by Sergei Trofimovich on 20 May 2011, 20:20:30 UTC, committed by Chris Mason on 23 May 2011, 17:24:14 UTC
Observed as a large delay when --mixed filesystem is filled up. Test example: 1. create tiny --mixed FS: $ dd if=/dev/zero of=2G.img seek=$((2048 * 1024 * 1024 - 1)) count=1 bs=1 $ mkfs.btrfs --mixed 2G.img $ mount -oloop 2G.img /mnt/ut/ 2. Try to fill it up: $ dd if=/dev/urandom of=10M.file bs=10240 count=1024 $ seq 1 256 | while read file_no; do echo $file_no; time cp 10M.file ${file_no}.copy; done Up to '200.copy' it goes fast, but when disk fills-up each -ENOSPC message takes 3 seconds to pop-up _every_ ENOSPC (and in usermode linux it's even more: 30-60 seconds!). (Maybe, time depends on kernel's timer resolution). No IO, no CPU load, just rescheduling. Some debugging revealed busy spinning in shrink_delalloc. Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Reviewed-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
1 parent 0f3b708
copy_page.S
/*
* arch/alpha/lib/copy_page.S
*
* Copy an entire page.
*/
.text
.align 4
.global copy_page
.ent copy_page
copy_page:
.prologue 0
lda $18,128
nop
unop
nop
1: ldq $0,0($17)
ldq $1,8($17)
ldq $2,16($17)
ldq $3,24($17)
ldq $4,32($17)
ldq $5,40($17)
ldq $6,48($17)
ldq $7,56($17)
stq $0,0($16)
subq $18,1,$18
stq $1,8($16)
addq $17,64,$17
stq $2,16($16)
stq $3,24($16)
stq $4,32($16)
stq $5,40($16)
stq $6,48($16)
stq $7,56($16)
addq $16,64,$16
bne $18, 1b
ret
nop
unop
nop
.end copy_page
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...