diff options
| author | Russ Cox <rsc@golang.org> | 2025-03-04 10:31:02 -0500 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2025-04-11 12:24:59 -0700 |
| commit | 3968a5bca4fc0cdb4e2bb9fd6169deafdafc420d (patch) | |
| tree | d78415165d6bbc9f77fc38a452a12217fb675bfd /src/runtime/runtime2.go | |
| parent | c77ada1b78ae83c88a4e964a7cbfa2e708073d8b (diff) | |
| download | go-3968a5bca4fc0cdb4e2bb9fd6169deafdafc420d.tar.xz | |
runtime: handle m0 padding better
The SpinbitMutex experiment requires m structs other than m0
to be allocated in 2048-byte size class, by adding padding.
Do the calculation more explicitly, to avoid future CLs like CL 653335.
Change-Id: I83ae1e86ef3711ab65441f4e487f94b9e1429029
Reviewed-on: https://go-review.googlesource.com/c/go/+/654595
Reviewed-by: Rhys Hiltner <rhys.hiltner@gmail.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Diffstat (limited to 'src/runtime/runtime2.go')
| -rw-r--r-- | src/runtime/runtime2.go | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go index 6b9f49d503..4318930d9c 100644 --- a/src/runtime/runtime2.go +++ b/src/runtime/runtime2.go @@ -619,13 +619,18 @@ type m struct { // Up to 10 locks held by this m, maintained by the lock ranking code. locksHeldLen int locksHeld [10]heldLockInfo +} + +const mRedZoneSize = (16 << 3) * asanenabledBit // redZoneSize(2048) + +type mPadded struct { + m // Size the runtime.m structure so it fits in the 2048-byte size class, and // not in the next-smallest (1792-byte) size class. That leaves the 11 low // bits of muintptr values available for flags, as required for // GOEXPERIMENT=spinbitmutex. - _ [goexperiment.SpinbitMutexInt * 64 * goarch.PtrSize / 8]byte - _ [goexperiment.SpinbitMutexInt * 700 * (2 - goarch.PtrSize/4)]byte + _ [goexperiment.SpinbitMutexInt * (2048 - mallocHeaderSize - mRedZoneSize - unsafe.Sizeof(m{}))]byte } type p struct { |