runtime: reduced struct sizes found via pahole
During my research of pahole with Go structs, I've found couple of
structs in runtime/ pkg where we can reduce several structs' sizes
highligted by pahole tool which detect byte holes and paddings.
Overall, there are 80 bytes reduced.
Change-Id: I398e5ed6f5b199394307741981cb5ad5b875e98f
Reviewed-on: https://go-review.googlesource.com/c/go/+/578795
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Joedian Reid <joedian@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
diff --git a/src/runtime/mgclimit.go b/src/runtime/mgclimit.go
index bd6dc37..ad86fbd 100644
--- a/src/runtime/mgclimit.go
+++ b/src/runtime/mgclimit.go
@@ -33,16 +33,6 @@
lock atomic.Uint32
enabled atomic.Bool
- bucket struct {
- // Invariants:
- // - fill >= 0
- // - capacity >= 0
- // - fill <= capacity
- fill, capacity uint64
- }
- // overflow is the cumulative amount of GC CPU time that we tried to fill the
- // bucket with but exceeded its capacity.
- overflow uint64
// gcEnabled is an internal copy of gcBlackenEnabled that determines
// whether the limiter tracks total assist time.
@@ -55,6 +45,20 @@
// the mark and sweep phases.
transitioning bool
+ // test indicates whether this instance of the struct was made for testing purposes.
+ test bool
+
+ bucket struct {
+ // Invariants:
+ // - fill >= 0
+ // - capacity >= 0
+ // - fill <= capacity
+ fill, capacity uint64
+ }
+ // overflow is the cumulative amount of GC CPU time that we tried to fill the
+ // bucket with but exceeded its capacity.
+ overflow uint64
+
// assistTimePool is the accumulated assist time since the last update.
assistTimePool atomic.Int64
@@ -77,9 +81,6 @@
//
// gomaxprocs isn't used directly so as to keep this structure unit-testable.
nprocs int32
-
- // test indicates whether this instance of the struct was made for testing purposes.
- test bool
}
// limiting returns true if the CPU limiter is currently enabled, meaning the Go GC
diff --git a/src/runtime/mgcscavenge.go b/src/runtime/mgcscavenge.go
index dede4a1..8102940 100644
--- a/src/runtime/mgcscavenge.go
+++ b/src/runtime/mgcscavenge.go
@@ -281,15 +281,19 @@
// g is the goroutine the scavenger is bound to.
g *g
- // parked is whether or not the scavenger is parked.
- parked bool
-
// timer is the timer used for the scavenger to sleep.
timer *timer
// sysmonWake signals to sysmon that it should wake the scavenger.
sysmonWake atomic.Uint32
+ // parked is whether or not the scavenger is parked.
+ parked bool
+
+ // printControllerReset instructs printScavTrace to signal that
+ // the controller was reset.
+ printControllerReset bool
+
// targetCPUFraction is the target CPU overhead for the scavenger.
targetCPUFraction float64
@@ -312,10 +316,6 @@
// value. Used if the controller's assumptions fail to hold.
controllerCooldown int64
- // printControllerReset instructs printScavTrace to signal that
- // the controller was reset.
- printControllerReset bool
-
// sleepStub is a stub used for testing to avoid actually having
// the scavenger sleep.
//
diff --git a/src/runtime/netpoll.go b/src/runtime/netpoll.go
index 6a73f70..bbfef80 100644
--- a/src/runtime/netpoll.go
+++ b/src/runtime/netpoll.go
@@ -102,14 +102,14 @@
lock mutex // protects the following fields
closing bool
+ rrun bool // whether rt is running
+ wrun bool // whether wt is running
user uint32 // user settable cookie
rseq uintptr // protects from stale read timers
rt timer // read deadline timer
- rrun bool // whether rt is running
rd int64 // read deadline (a nanotime in the future, -1 when expired)
wseq uintptr // protects from stale write timers
wt timer // write deadline timer
- wrun bool // whether wt is running
wd int64 // write deadline (a nanotime in the future, -1 when expired)
self *pollDesc // storage for indirect interface. See (*pollDesc).makeArg.
}
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 1468c7c..e469f20 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -6024,8 +6024,8 @@
type sysmontick struct {
schedtick uint32
- schedwhen int64
syscalltick uint32
+ schedwhen int64
syscallwhen int64
}
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index b58255f..0093a6d 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -510,12 +510,12 @@
sleepWhen int64 // when to sleep until
selectDone atomic.Uint32 // are we participating in a select and did someone win the race?
- coroarg *coro // argument during coroutine transfers
-
// goroutineProfiled indicates the status of this goroutine's stack for the
// current in-progress goroutine profile
goroutineProfiled goroutineProfileStateHolder
+ coroarg *coro // argument during coroutine transfers
+
// Per-G tracer state.
trace gTraceState
@@ -604,8 +604,8 @@
// there's no stack to put them on. That is their sole purpose.
waitunlockf func(*g, unsafe.Pointer) bool
waitlock unsafe.Pointer
- waitTraceBlockReason traceBlockReason
waitTraceSkip int
+ waitTraceBlockReason traceBlockReason
syscalltick uint32
freelink *m // on sched.freem
diff --git a/src/runtime/sizeof_test.go b/src/runtime/sizeof_test.go
index d235d6a..43aba98 100644
--- a/src/runtime/sizeof_test.go
+++ b/src/runtime/sizeof_test.go
@@ -20,7 +20,7 @@
_32bit uintptr // size on 32bit platforms
_64bit uintptr // size on 64bit platforms
}{
- {runtime.G{}, 272, 440}, // g, but exported for testing
+ {runtime.G{}, 272, 432}, // g, but exported for testing
{runtime.Sudog{}, 56, 88}, // sudog, but exported for testing
}
diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go
index bfe4153..a7ce9c3 100644
--- a/src/runtime/symtab.go
+++ b/src/runtime/symtab.go
@@ -401,13 +401,12 @@
modulehashes []modulehash
hasmain uint8 // 1 if module contains the main function, 0 otherwise
+ bad bool // module failed to load and should be ignored
gcdatamask, gcbssmask bitvector
typemap map[typeOff]*_type // offset to *_rtype in previous module
- bad bool // module failed to load and should be ignored
-
next *moduledata
}
