Re: Kernel 2.6.8.1: swap storm of death - CFQ scheduler=culprit

Karl Vogel
2004-08-22T19:18:25Z

When using elevator=as I'm unable to trigger the swap of death, so it seems
that the CFQ scheduler is at blame here.

With AS scheduler, the system recovers in +-10 seconds, vmstat output during
that time:

procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
1 0 0 295632 40372 49400 87 278 324 303 1424 784 7 2 78 13
0 0 0 295632 40372 49400 0 0 0 0 1210 648 3 1 96 0
0 0 0 295632 40372 49400 0 0 0 0 1209 652 4 0 96 0
2 0 0 112784 40372 49400 0 0 0 0 1204 630 23 34 43 0
1 9 156236 788 264 8128 28 156220 3012 156228 3748 3655 11 31 0 59
0 15 176656 2196 280 8664 0 20420 556 20436 1108 374 2 5 0 93
0 17 205320 724 232 7960 28 28664 396 28664 1118 503 7 12 0 81
2 12 217892 1812 252 8556 248 12584 864 12584 1495 318 2 7 0 91
4 14 253268 2500 268 8728 188 35392 432 35392 1844 399 3 7 0 90
0 13 255692 1188 288 9152 960 2424 1408 2424 1173 2215 10 5 0 85
0 7 266140 2288 312 9276 604 10468 752 10468 1248 644 5 5 0 90
0 7 190516 340636 348 9860 1400 0 2016 0 1294 817 4 8 0 88
1 8 190516 339460 384 10844 552 0 1556 4 1241 642 3 1 0 96
1 3 190516 337084 404 11968 1432 0 2576 4 1292 788 3 1 0 96
0 6 190516 333892 420 13612 1844 0 3500 0 1343 850 5 2 0 93
0 1 190516 333700 424 13848 480 0 720 0 1250 654 3 2 0 95
0 1 190516 334468 424 13848 188 0 188 0 1224 589 3 2 0 95

With CFQ processes got stuck in 'D' and never left that state. See URL's in my
initial post for diagnostics.