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runtime: fix data race in Plan9 sysalloc

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Add mutex to protect brk limit.
Add mstats.sys update.

R=rsc
CC=golang-dev
https://golang.org/cl/4762045
This commit is contained in:
Dmitriy Vyukov 2011-07-18 10:50:04 -04:00 committed by Russ Cox
parent e8689404a7
commit c1f035ba4c
1 changed files with 10 additions and 1 deletions
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11
src/pkg/runtime/plan9/mem.c
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@ -8,6 +8,7 @@
extern byte end[];
static byte *bloc = { end };
static Lock memlock;
enum
{
@ -19,23 +20,31 @@ runtime·SysAlloc(uintptr nbytes)
{
uintptr bl;
runtime·lock(&memlock);
mstats.sys += nbytes;
// Plan 9 sbrk from /sys/src/libc/9sys/sbrk.c
bl = ((uintptr)bloc + Round) & ~Round;
if(runtime·brk_((void*)(bl + nbytes)) < 0)
if(runtime·brk_((void*)(bl + nbytes)) < 0) {
runtime·unlock(&memlock);
return (void*)-1;
}
bloc = (byte*)bl + nbytes;
runtime·unlock(&memlock);
return (void*)bl;
}
void
runtime·SysFree(void *v, uintptr nbytes)
{
runtime·lock(&memlock);
mstats.sys -= nbytes;
// from tiny/mem.c
// Push pointer back if this is a free
// of the most recent SysAlloc.
nbytes += (nbytes + Round) & ~Round;
if(bloc == (byte*)v+nbytes)
bloc -= nbytes;
runtime·unlock(&memlock);
}
void