Re: [9fans] plan 9 overcommits memory?

[erik quanstrom <quanstro@quanstro.net>]

>> The current swap just frustrates people who expect it to work, and
>> then have their systems freeze randomly. Maybe by disabling/remove
>> swap support, then if someone really needs swap he will fix it first
>> and then we can add it back.
>
> i'm not sure all the random freezes are caused by swap.
> in a way, it would be nice if they were, but i wonder...

probablly not.

i am currently tracking down a problem on my amd system
at home.  the fault seems paging related, but i don't have any
configured "swap" partition.

this fault is during demand loading.

- erik

cpu0: registers for smtpd 36123
FLAGS=10206 TRAP=E ECODE=0 PC=F018BF4C SS=5C88 USP=F025194C
  AX F0059E1C  BX F0059018  CX 00827424  DX 0000F000
  SI 0000F000  DI 00010000  BP 00000000
  CS 0010  DS 0008  ES 0008  FS 001B  GS 001B
  CR0 80010039 CR2 00827458 CR3 08e5c000 CR4 000000d0
  MCA 177e882776 MCT 00000000
  ur f367e4c0 up f02d1ab8
panic: fault: 0x827458

ktrace ->

src(0xf0108b6e); // dumpstack+0x10
src(0xf014ddb6); // panic+0xfe
src(0xf0108d8c); // fault386+0x17d
src(0xf010832f); // trap+0x15d
src(0xf010062a); // forkret
//passing interrupt frame; last pc found at sp=0xf367e4b8
src(0xf018bf4c); // lookpage+0x2f
src(0xf018ab7e); // pio+0x34
src(0xf018aaaf); // fixfault+0x337
src(0xf018a663); // fault+0xc8
src(0xf0108d52); // fault386+0x143
src(0xf010832f); // trap+0x15d
src(0xf010062a); // forkret


acid: src(0xf018bf4c); // lookpage+0x2f
/sys/src/9/port/page.c:441
 4 439		lock(&palloc.hashlock);
 440		for(f = pghash(daddr); f; f = f->hash) {
>441			if(f->image == i && f->daddr == daddr) {

/sys/src/9/port/fault.c:198
  196		if(loadrec == 0) {	/* from a text/data image */
 197			daddr = s->fstart+soff;
>198			new = lookpage(s->image, daddr);
 199			if(new != nil) {

/sys/src/9/port/fault.c:90
  88		case SG_TEXT: 			/* Demand load */
 89			if(pagedout(*pg))
>90				pio(s, addr, soff, pg);