mirror of
https://github.com/golang/go
synced 2024-10-04 14:31:21 -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
99 lines
2.5 KiB
C
99 lines
2.5 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 "os_GOOS.h"
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#include "defs_GOOS_GOARCH.h"
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#include "malloc.h"
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enum {
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MEM_COMMIT = 0x1000,
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MEM_RESERVE = 0x2000,
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MEM_DECOMMIT = 0x4000,
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MEM_RELEASE = 0x8000,
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PAGE_READWRITE = 0x0004,
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PAGE_NOACCESS = 0x0001,
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};
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#pragma dynimport runtime·VirtualAlloc VirtualAlloc "kernel32.dll"
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#pragma dynimport runtime·VirtualFree VirtualFree "kernel32.dll"
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#pragma dynimport runtime·VirtualProtect VirtualProtect "kernel32.dll"
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extern void *runtime·VirtualAlloc;
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extern void *runtime·VirtualFree;
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extern void *runtime·VirtualProtect;
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void*
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runtime·SysAlloc(uintptr n, uint64 *stat)
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{
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runtime·xadd64(stat, n);
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return runtime·stdcall(runtime·VirtualAlloc, 4, nil, n, (uintptr)(MEM_COMMIT|MEM_RESERVE), (uintptr)PAGE_READWRITE);
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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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void *r;
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r = runtime·stdcall(runtime·VirtualFree, 3, v, n, (uintptr)MEM_DECOMMIT);
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if(r == nil)
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runtime·throw("runtime: failed to decommit pages");
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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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void *r;
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r = runtime·stdcall(runtime·VirtualAlloc, 4, v, n, (uintptr)MEM_COMMIT, (uintptr)PAGE_READWRITE);
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if(r != v)
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runtime·throw("runtime: failed to commit pages");
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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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uintptr r;
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runtime·xadd64(stat, -(uint64)n);
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r = (uintptr)runtime·stdcall(runtime·VirtualFree, 3, v, (uintptr)0, (uintptr)MEM_RELEASE);
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if(r == 0)
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runtime·throw("runtime: failed to release pages");
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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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uintptr r, old;
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r = (uintptr)runtime·stdcall(runtime·VirtualProtect, 4, v, n, (uintptr)PAGE_NOACCESS, &old);
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if(r == 0)
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runtime·throw("runtime: failed to protect pages");
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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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// v is just a hint.
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// First try at v.
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v = runtime·stdcall(runtime·VirtualAlloc, 4, v, n, (uintptr)MEM_RESERVE, (uintptr)PAGE_READWRITE);
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if(v != nil)
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return v;
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// Next let the kernel choose the address.
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return runtime·stdcall(runtime·VirtualAlloc, 4, nil, n, (uintptr)MEM_RESERVE, (uintptr)PAGE_READWRITE);
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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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p = runtime·stdcall(runtime·VirtualAlloc, 4, v, n, (uintptr)MEM_COMMIT, (uintptr)PAGE_READWRITE);
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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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