Re: [PATCH] Recent VM fiasco - fixed

Steve Dodd
2000-05-11T17:38:05Z

On Wed, May 10, 2000 at 05:16:05PM -0700, Linus Torvalds wrote:

[..]
> Just the dirty buffer handling made quite an enormous difference, so
> please do test this if you hated earlier pre7 kernels.

I definitely hate pre7-9.

For various reasons, I'm stuck on a 16Mb box right now. I just tried to start
dselect[0], and it got killed. It's completely repeatable, and running vmstat
shows that something demented is happening:

frodo:~$ vmstat 1 # and then start dselect on another terminal
procs memory swap io system cpu
r b w swpd free buff cache si so bi bo in cs us sy id
0 0 0 2508 6544 196 5124 6 4 94 9 137 56 40 5 55
0 0 0 2508 6524 196 5140 0 0 16 0 134 4 0 2 98
0 0 0 2508 6524 196 5140 0 0 0 0 106 2 0 2 98
0 0 0 2508 6520 200 5140 0 0 1 0 112 6 0 2 98
0 0 0 2508 6200 204 5224 16 0 77 0 125 29 4 4 92
0 0 0 2508 6200 204 5224 0 0 0 0 103 2 0 2 98
1 0 0 2508 5332 212 5504 0 0 285 0 117 21 42 4 54
1 0 0 2508 3748 216 6004 0 0 501 0 119 24 83 7 11
1 0 0 2508 2664 220 6388 0 0 389 69 164 20 55 5 40
1 0 0 2508 964 224 7020 0 0 631 0 117 15 83 6 11
1 0 0 2508 364 216 6692 0 0 341 0 113 22 81 15 5
1 0 0 2504 288 208 5900 0 0 512 0 114 18 78 22 0
1 0 0 2504 364 112 5068 0 0 514 0 114 25 77 18 5
1 0 1 2504 252 72 4416 0 0 483 12 137 47 73 15 13
1 0 0 2504 264 68 4448 0 0 511 13 147 77 32 20 48
VM: killing process dselect
0 2 0 2504 8044 76 3960 176 0 803 0 220 137 16 23 61
0 0 0 2504 8032 76 3964 0 0 2 0 106 8 0 2 98
0 0 0 2504 8032 76 3964 0 0 1 0 105 6 0 2 98

I'm not an "mm person", but that doesn't look optimal to me.

The box does have a reasonable amount of swap:

frodo:~$ cat /proc/swaps
Filename Type Size Used Priority
/dev/hdc2 partition 18140 2480 -1
/dev/hdc4 partition 50396 0 -2

[0] so I could install the libbfd header files to compile kdb to poke at the
loop device lock-up stuff so I can use loop for testing ntfs stuff.. I'm
stuck in a maze of twisty kernel bugs, none alike..