diff options
Diffstat (limited to 'src/runtime/stack1.go')
| -rw-r--r-- | src/runtime/stack1.go | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/src/runtime/stack1.go b/src/runtime/stack1.go index 933e3d0b28..cb2110efb6 100644 --- a/src/runtime/stack1.go +++ b/src/runtime/stack1.go @@ -575,7 +575,7 @@ func copystack(gp *g, newsize uintptr) { fillstack(new, 0xfd) } if stackDebug >= 1 { - print("copystack gp=", gp, " [", hex(old.lo), " ", hex(old.hi-used), " ", hex(old.hi), "]/", old.hi-old.lo, " -> [", 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), "]/", gp.stackAlloc, " -> [", hex(new.lo), " ", hex(new.hi-used), " ", hex(new.hi), "]/", newsize, "\n") } // adjust pointers in the to-be-copied frames @@ -832,12 +832,19 @@ func shrinkstack(gp *g) { oldsize := gp.stackAlloc newsize := oldsize / 2 + // Don't shrink the allocation below the minimum-sized stack + // allocation. if newsize < _FixedStack { - return // don't shrink below the minimum-sized stack + return } - used := gp.stack.hi - gp.sched.sp - if used >= oldsize/4 { - return // still using at least 1/4 of the segment. + // Compute how much of the stack is currently in use and only + // shrink the stack if gp is using less than a quarter of its + // current stack. The currently used stack includes everything + // down to the SP plus the stack guard space that ensures + // there's room for nosplit functions. + avail := gp.stack.hi - gp.stack.lo + if used := gp.stack.hi - gp.sched.sp + _StackLimit; used >= avail/4 { + return } // We can't copy the stack if we're in a syscall. |