Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

runtime: remove old stack scanning code

Browse source 
This removes scang and preemptscan, since the stack scanning code now
uses suspendG.

For #10958, #24543.

Change-Id: Ic868bf5d6dcce40662a82cb27bb996cb74d0720e
Reviewed-on: https://go-review.googlesource.com/c/go/+/201138
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Austin Clements 2019-09-27 12:31:33 -04:00
parent 3f834114ab
commit 1b79afe460
3 changed files with 1 additions and 142 deletions
Download patch file Download diff file Expand all files Collapse all files

29
src/runtime/stack.go
View file

@ -916,7 +916,7 @@ func round2(x int32) int32 {
// Stack growth is multiplicative, for constant amortized cost.
//
// g->atomicstatus will be Grunning or Gscanrunning upon entry.
// If the GC is trying to stop this g then it will set preemptscan to true.
// If the scheduler is trying to stop this g, then it will set preemptStop.
//
// This must be nowritebarrierrec because it can be called as part of
// stack growth from other nowritebarrierrec functions, but the
@ -1022,34 +1022,7 @@ func newstack() {
preemptPark(gp) // never returns
}
// Synchronize with scang.
casgstatus(gp, _Grunning, _Gwaiting)
if gp.preemptscan {
for !castogscanstatus(gp, _Gwaiting, _Gscanwaiting) {
// Likely to be racing with the GC as
// it sees a _Gwaiting and does the
// stack scan. If so, gcworkdone will
// be set and gcphasework will simply
// return.
}
if !gp.gcscandone {
// gcw is safe because we're on the
// system stack.
gcw := &gp.m.p.ptr().gcw
scanstack(gp, gcw)
gp.gcscandone = true
}
gp.preemptscan = false
gp.preempt = false
casfrom_Gscanstatus(gp, _Gscanwaiting, _Gwaiting)
// This clears gcscanvalid.
casgstatus(gp, _Gwaiting, _Grunning)
gp.stackguard0 = gp.stack.lo + _StackGuard
gogo(&gp.sched) // never return
}
// Act like goroutine called runtime.Gosched.
casgstatus(gp, _Gwaiting, _Grunning)
gopreempt_m(gp) // never return
}