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| author | Keith Randall <khr@golang.org> | 2025-02-11 15:02:08 -0800 |
|---|---|---|
| committer | Keith Randall <khr@golang.org> | 2025-04-25 12:21:48 -0700 |
| commit | 3f3782feed6e0726ddb08afd32dad7d94fbb38c6 (patch) | |
| tree | 1fdceec931e4169b405a1909f624b7987b1adc6b /src/cmd/internal/obj/mips | |
| parent | dc1e255104f3fee2589da61b7fa80627beb885f4 (diff) | |
| download | go-3f3782feed6e0726ddb08afd32dad7d94fbb38c6.tar.xz | |
cmd/compile: allow all of the preamble to be preemptible
We currently make some parts of the preamble unpreemptible because
it confuses morestack. See comments in the code.
Instead, have morestack handle those weird cases so we can
remove unpreemptible marks from most places.
This CL makes user functions preemptible everywhere if they have no
write barriers (at least, on x86). In cmd/go the fraction of functions
that need preemptible markings drops from 82% to 36%. Makes the cmd/go
binary 0.3% smaller.
Update #35470
Change-Id: Ic83d5eabfd0f6d239a92e65684bcce7e67ff30bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/648518
Auto-Submit: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Diffstat (limited to 'src/cmd/internal/obj/mips')
| -rw-r--r-- | src/cmd/internal/obj/mips/obj0.go | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/src/cmd/internal/obj/mips/obj0.go b/src/cmd/internal/obj/mips/obj0.go index b9152fe57e..ef242c5f3b 100644 --- a/src/cmd/internal/obj/mips/obj0.go +++ b/src/cmd/internal/obj/mips/obj0.go @@ -767,12 +767,6 @@ func (c *ctxt0) stacksplit(p *obj.Prog, framesize int32) *obj.Prog { p.To.Type = obj.TYPE_REG p.To.Reg = REG_R1 - // Mark the stack bound check and morestack call async nonpreemptible. - // If we get preempted here, when resumed the preemption request is - // cleared, but we'll still call morestack, which will double the stack - // unnecessarily. See issue #35470. - p = c.ctxt.StartUnsafePoint(p, c.newprog) - var q *obj.Prog if framesize <= abi.StackSmall { // small stack: SP < stackguard @@ -876,8 +870,6 @@ func (c *ctxt0) stacksplit(p *obj.Prog, framesize int32) *obj.Prog { } p.Mark |= BRANCH - p = c.ctxt.EndUnsafePoint(p, c.newprog, -1) - // JMP start p = obj.Appendp(p, c.newprog) |