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runtime: remove g.stackAlloc

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Since we're no longer stealing space for the stack barrier array from
the stack allocation, the stack allocation is simply
g.stack.hi-g.stack.lo.

Updates #17503.

Change-Id: Id9b450ae12c3df9ec59cfc4365481a0a16b7c601
Reviewed-on: https://go-review.googlesource.com/36621
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
This commit is contained in:
Austin Clements 2017-02-09 14:11:13 -05:00
parent d089a6c718
commit 0993b2fd06
4 changed files with 13 additions and 21 deletions
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19
src/runtime/stack.go
View file

@ -415,9 +415,10 @@ func stackalloc(n uint32) stack {
// resources and must not split the stack.
//
//go:systemstack
func stackfree(stk stack, n uintptr) {
func stackfree(stk stack) {
gp := getg()
v := unsafe.Pointer(stk.lo)
n := stk.hi - stk.lo
if n&(n-1) != 0 {
throw("stack not a power of 2")
}
@ -852,7 +853,7 @@ func copystack(gp *g, newsize uintptr, sync bool) {
fillstack(new, 0xfd)
}
if stackDebug >= 1 {
print("copystack gp=", gp, " [", hex(old.lo), " ", hex(old.hi-used), " ", hex(old.hi), "]/", gp.stackAlloc, " -> [", hex(new.lo), " ", hex(new.hi-used), " ", hex(new.hi), "]/", newsize, "\n")
print("copystack gp=", gp, " [", hex(old.lo), " ", hex(old.hi-used), " ", hex(old.hi), "]", " -> [", hex(new.lo), " ", hex(new.hi-used), " ", hex(new.hi), "]/", newsize, "\n")
}
// Compute adjustment.
@ -895,8 +896,6 @@ func copystack(gp *g, newsize uintptr, sync bool) {
gp.stack = new
gp.stackguard0 = new.lo + _StackGuard // NOTE: might clobber a preempt request
gp.sched.sp = new.hi - used
oldsize := gp.stackAlloc
gp.stackAlloc = newsize
gp.stktopsp += adjinfo.delta
// Adjust pointers in the new stack.
@ -906,7 +905,7 @@ func copystack(gp *g, newsize uintptr, sync bool) {
if stackPoisonCopy != 0 {
fillstack(old, 0xfc)
}
stackfree(old, oldsize)
stackfree(old)
}
// round x up to a power of 2.
@ -1051,9 +1050,9 @@ func newstack(ctxt unsafe.Pointer) {
}
// Allocate a bigger segment and move the stack.
oldsize := int(gp.stackAlloc)
oldsize := gp.stack.hi - gp.stack.lo
newsize := oldsize * 2
if uintptr(newsize) > maxstacksize {
if newsize > maxstacksize {
print("runtime: goroutine stack exceeds ", maxstacksize, "-byte limit\n")
throw("stack overflow")
}
@ -1064,7 +1063,7 @@ func newstack(ctxt unsafe.Pointer) {
// The concurrent GC will not scan the stack while we are doing the copy since
// the gp is in a Gcopystack status.
copystack(gp, uintptr(newsize), true)
copystack(gp, newsize, true)
if stackDebug >= 1 {
print("stack grow done\n")
}
@ -1098,7 +1097,7 @@ func shrinkstack(gp *g) {
if gp.stack.lo != 0 {
// Free whole stack - it will get reallocated
// if G is used again.
stackfree(gp.stack, gp.stackAlloc)
stackfree(gp.stack)
gp.stack.lo = 0
gp.stack.hi = 0
}
@ -1120,7 +1119,7 @@ func shrinkstack(gp *g) {
return
}
oldsize := gp.stackAlloc
oldsize := gp.stack.hi - gp.stack.lo
newsize := oldsize / 2
// Don't shrink the allocation below the minimum-sized stack
// allocation.