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| author | Andy Pan <panjf2000@gmail.com> | 2021-05-06 09:04:03 +0800 |
|---|---|---|
| committer | Austin Clements <austin@google.com> | 2021-08-31 13:54:19 +0000 |
| commit | 3920d6f2085559ae262d651b00bf8b29f953580a (patch) | |
| tree | 423aa9be3d75bdd06a34ab19a916ad1ce52ed7ba /src/runtime/proc.go | |
| parent | f118d145a56be294e578fb20e0e2fdde2a92846d (diff) | |
| download | go-3920d6f2085559ae262d651b00bf8b29f953580a.tar.gz go-3920d6f2085559ae262d651b00bf8b29f953580a.zip | |
runtime: eliminate the redundant for loop in runqget()
Change-Id: If9b283bbef3ff12a64d34b07491aee3396852f05
Reviewed-on: https://go-review.googlesource.com/c/go/+/317509
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/runtime/proc.go')
| -rw-r--r-- | src/runtime/proc.go | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 55023e3f9f..197441dfa7 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -5994,14 +5994,12 @@ func runqputbatch(pp *p, q *gQueue, qsize int) { // Executed only by the owner P. func runqget(_p_ *p) (gp *g, inheritTime bool) { // If there's a runnext, it's the next G to run. - for { - next := _p_.runnext - if next == 0 { - break - } - if _p_.runnext.cas(next, 0) { - return next.ptr(), true - } + next := _p_.runnext + // If the runnext is non-0 and the CAS fails, it could only have been stolen by another P, + // because other Ps can race to set runnext to 0, but only the current P can set it to non-0. + // Hence, there's no need to retry this CAS if it falls. + if next != 0 && _p_.runnext.cas(next, 0) { + return next.ptr(), true } for { |