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runtime: new allocation strategy for amd64

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Do not reserve virtual address space.
Instead, assume it will be there when we need it,
and crash loudly if that assumption is violated.
Reserving the address space gets charged to
ulimit -v, which exceeds commonly set limits.

http://groups.google.com/group/golang-dev/msg/7c477af5f5a8dd2c

R=r, niemeyer
CC=golang-dev
https://golang.org/cl/4148045
This commit is contained in:
Russ Cox 2011-02-09 14:38:33 -05:00
parent 56faae21d2
commit 5b1b2ba9c7
3 changed files with 35 additions and 3 deletions
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17
src/pkg/runtime/freebsd/mem.c
View File

@ -33,6 +33,12 @@ runtime·SysFree(void *v, uintptr n)
void*
runtime·SysReserve(void *v, uintptr n)
{
// On 64-bit, people with ulimit -v set complain if we reserve too
// much address space. Instead, assume that the reservation is okay
// and check the assumption in SysMap.
if(sizeof(void*) == 8)
return v;
return runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
}
@ -42,6 +48,17 @@ runtime·SysMap(void *v, uintptr n)
void *p;
mstats.sys += n;
// On 64-bit, we don't actually have v reserved, so tread carefully.
if(sizeof(void*) == 8) {
p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0);
if(p != v) {
runtime·printf("runtime: address space conflict: map(%v) = %v\n", v, p);
runtime·throw("runtime: address space conflict");
}
return;
}
p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
if(p != v)
runtime·throw("runtime: cannot map pages in arena address space");

17
src/pkg/runtime/linux/mem.c
View File

@ -39,6 +39,12 @@ runtime·SysFree(void *v, uintptr n)
void*
runtime·SysReserve(void *v, uintptr n)
{
// On 64-bit, people with ulimit -v set complain if we reserve too
// much address space. Instead, assume that the reservation is okay
// and check the assumption in SysMap.
if(sizeof(void*) == 8)
return v;
return runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
}
@ -48,6 +54,17 @@ runtime·SysMap(void *v, uintptr n)
void *p;
mstats.sys += n;
// On 64-bit, we don't actually have v reserved, so tread carefully.
if(sizeof(void*) == 8) {
p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0);
if(p != v) {
runtime·printf("runtime: address space conflict: map(%v) = %v\n", v, p);
runtime·throw("runtime: address space conflict");
}
return;
}
p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
if(p != v)
runtime·throw("runtime: cannot map pages in arena address space");

4
test/run
View File

@ -42,9 +42,7 @@ TMP2FILE=/tmp/gotest2-$$-$USER
# don't run the machine out of memory: limit individual processes to 4GB.
# on thresher, 3GB suffices to run the tests; with 2GB, peano fails.
# Linux charges reserved but not mapped addresses to ulimit -v
# so we have to use ulimit -m.
ulimit -m 4000000
ulimit -v 4000000
# no core files please
ulimit -c 0