From: Ian Lance Taylor <iant@golang.org>
Date: Fri, 22 Oct 2021 21:19:34 +0000 (-0700)
Subject: internal/poll: avoid tiny allocator for splicePipe
X-Git-Tag: go1.18beta1~767
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=60c3069dd82eee30c00f2a8d829ba74b11bcf07e;p=gostls13.git

internal/poll: avoid tiny allocator for splicePipe

We want to set a finalizer on splicePipe, so make it large enough to
not use the tiny allocator. Otherwise the finalizer will not run until
the rest of the tiny allocation can be freed. This only matters on
32-bit systems.

Fixes #48968

Change-Id: I8eb3c9f48fdccab7dc79c5b918d4257b6151ee91
Reviewed-on: https://go-review.googlesource.com/c/go/+/358114
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
---

diff --git a/src/internal/poll/splice_linux.go b/src/internal/poll/splice_linux.go
index 8062d98fae..6869a40b24 100644
--- a/src/internal/poll/splice_linux.go
+++ b/src/internal/poll/splice_linux.go
@@ -158,6 +158,10 @@ type splicePipe struct {
 	rfd  int
 	wfd  int
 	data int
+
+	// We want to use a finalizer, so ensure that the size is
+	// large enough to not use the tiny allocator.
+	_ [24 - 3*unsafe.Sizeof(int(0))]byte
 }
 
 // splicePipePool caches pipes to avoid high-frequency construction and destruction of pipe buffers.