mirror of
https://github.com/golang/go
synced 2024-10-04 08:31:22 -06:00
1665b006a5
On stack overflow, if all frames on the stack are
copyable, we copy the frames to a new stack twice
as large as the old one. During GC, if a G is using
less than 1/4 of its stack, copy the stack to a stack
half its size.
TODO
- Do something about C frames. When a C frame is in the
stack segment, it isn't copyable. We allocate a new segment
in this case.
- For idempotent C code, we can abort it, copy the stack,
then retry. I'm working on a separate CL for this.
- For other C code, we can raise the stackguard
to the lowest Go frame so the next call that Go frame
makes triggers a copy, which will then succeed.
- Pick a starting stack size?
The plan is that eventually we reach a point where the
stack contains only copyable frames.
LGTM=rsc
R=dvyukov, rsc
CC=golang-codereviews
https://golang.org/cl/54650044
96 lines
2.0 KiB
C
96 lines
2.0 KiB
C
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "runtime.h"
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#include "arch_GOARCH.h"
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#include "defs_GOOS_GOARCH.h"
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#include "os_GOOS.h"
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#include "malloc.h"
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enum
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{
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ENOMEM = 12,
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};
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void*
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runtime·SysAlloc(uintptr n, uint64 *stat)
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{
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void *v;
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v = runtime·mmap(nil, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
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if(v < (void*)4096)
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return nil;
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runtime·xadd64(stat, n);
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return v;
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}
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void
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runtime·SysUnused(void *v, uintptr n)
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{
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runtime·madvise(v, n, MADV_FREE);
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}
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void
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runtime·SysUsed(void *v, uintptr n)
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{
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USED(v);
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USED(n);
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}
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void
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runtime·SysFree(void *v, uintptr n, uint64 *stat)
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{
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runtime·xadd64(stat, -(uint64)n);
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runtime·munmap(v, n);
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}
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void
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runtime·SysFault(void *v, uintptr n)
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{
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runtime·mmap(v, n, PROT_NONE, 0, -1, 0);
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}
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void*
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runtime·SysReserve(void *v, uintptr n)
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{
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void *p;
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// On 64-bit, people with ulimit -v set complain if we reserve too
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// much address space. Instead, assume that the reservation is okay
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// and check the assumption in SysMap.
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if(sizeof(void*) == 8)
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return v;
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p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
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if(p < (void*)4096)
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return nil;
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return p;
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}
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void
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runtime·SysMap(void *v, uintptr n, uint64 *stat)
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{
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void *p;
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runtime·xadd64(stat, n);
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// On 64-bit, we don't actually have v reserved, so tread carefully.
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if(sizeof(void*) == 8) {
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p = runtime·mmap(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
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if(p == (void*)ENOMEM)
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runtime·throw("runtime: out of memory");
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if(p != v) {
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runtime·printf("runtime: address space conflict: map(%p) = %p\n", v, p);
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runtime·throw("runtime: address space conflict");
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}
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return;
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}
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p = runtime·mmap(v, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
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if(p == (void*)ENOMEM)
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runtime·throw("runtime: out of memory");
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if(p != v)
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runtime·throw("runtime: cannot map pages in arena address space");
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}
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