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

Revert "cmd/compile: allow all of the preamble to be preemptible"

Browse source 
This reverts commits

3f3782feed (CL 648518)
b386b62852 (CL 668475)

Fixes #73542

Change-Id: I218851c5c0b62700281feb0b3f82b6b9b97b910d
Reviewed-on: https://go-review.googlesource.com/c/go/+/670055
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This commit is contained in:
Keith Randall 2025-05-05 10:51:52 -07:00 • committed by Gopher Robot
parent 6729fbe93e
commit fa2bb342d7
12 changed files with 127 additions and 59 deletions
Download patch file Download diff file Expand all files Collapse all files

23
src/runtime/stack.go
View file

@ -1075,29 +1075,6 @@ func newstack() {
gopreempt_m(gp) // never return
}
if stackguard0 == gp.stack.lo+stackGuard && gp.preemptRecent {
// The case happens because of an interaction between synchronous
// and asynchronous preemption. First, we set the cooperative
// preemption signal (g.stackguard0 = stackPreempt), and as a
// result the function fails the stack check and enters its
// morestack path. If it gets suspended at that point, we might
// give up waiting for it and send an async preempt. That async
// preempt gets processed and clears the cooperative preemption
// signal (g.stackguard0 = g.stack.lo+stackGuard) and resumes
// the function. But even though the cooperative preemption
// signal is cleared, we're already on the morestack path and
// can't avoid calling morestack. See issue 35470.
//
// To avoid this problem, if we've been preempted recently,
// clear the "preempted recently" flag and resume the G.
// If we really did need more stack, the morestack check will
// immediately fail and we'll get back here to try again (with
// preemptRecent==false, so we don't take this case the
// second time).
gp.preemptRecent = false
gogo(&gp.sched) // never return
}
// Allocate a bigger segment and move the stack.
oldsize := gp.stack.hi - gp.stack.lo
newsize := oldsize * 2