Re: [PATCH] Recent VM fiasco - fixed

Christoph Rohland
2000-05-10T11:25:16Z

Linus Torvalds <torvalds@transmeta.com> writes:

> On 9 May 2000, Christoph Rohland wrote:
>
> > Linus Torvalds <torvalds@transmeta.com> writes:
> >
> > > Try out the really recent one - pre7-8. So far it hassome good reviews,
> > > and I've tested it both on a 20MB machine and a 512MB one..

> > I append the mem and task info from sysrq. Mem info seems to not
> > change after lockup.
>
> I suspect that if you do right-alt + scrolllock, you'll see it looping on
> a spinlock. Which is why the memory info isn't changing ;)
>
> But I'll double-check the shm code (I didn't test anything that did any
> shared memory, for example).

Juan Quintela's patch fixes the lockup. shm paging locked up on the
page lock.

Now I can give more data about pre7-8. After a short run I can say the
following:

The machine seems to be stable, but VM is mainly unbalanced:

[root@ls3016 /root]# vmstat 5
procs memory swap io system cpu
r b w swpd free buff cache si so bi bo in cs us sy id

[...]

9 3 0 0 1460016 1588 11284 0 0 0 0 109 23524 4 96 0
9 3 1 7552 557432 1004 19320 0 1607 0 402 186 42582 2 89 9
11 1 1 41972 111368 424 53740 0 6884 2 1721 277 25904 0 89 10
11 1 0 48084 11896 276 59404 0 1133 1 284 181 4439 0 95 5
13 2 2 48352 466952 180 52960 5 158 4 39 230 6381 2 98 0
10 3 1 53400 934204 248 59940 498 1442 128 363 272 3953 1 99 0
11 3 1 52624 878696 300 59820 248 50 81 13 148 971 0 100 0
11 1 0 4556 883852 316 16164 855 0 214 1 127 25188 3 97 0
12 0 0 3936 525620 316 15544 0 0 0 0 109 33969 4 96 0
12 0 0 3936 2029556 316 15544 0 0 0 0 123 19659 4 96 0
11 1 0 3936 686856 316 15544 0 0 0 0 117 14370 3 97 0
12 0 0 3936 388176 320 15544 0 0 0 0 121 7477 3 97 0
10 3 1 47660 5216 88 19992 0 9353 0 2341 757 1267 0 97 3
VM: killing process ipctst
6 6 1 36792 484880 152 26892 65 12307 21 3078 1619 2184 0 94 6
procs memory swap io system cpu
r b w swpd free buff cache si so bi bo in cs us sy id
10 1 1 39620 66736 148 29364 8 494 2 125 327 1980 0 100 0
VM: killing process ipctst
9 2 1 46536 627356 116 31072 87 8675 23 2169 1784 1412 0 96 4
10 0 1 46664 617368 116 31200 0 26 0 6 258 112 0 100 0
10 0 1 47300 607184 116 31832 0 126 0 32 291 110 0 100 0

So we are swapping out with lots of free memory and killing random
processes. The machine also becomes quite unresponsive compared to
pre4 on the same tests.

Greetings
Christoph

--
Christoph Rohland Tel: +49 6227 748201
SAP AG Fax: +49 6227 758201
LinuxLab Email: cr@sap.com