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| author | Michael Anthony Knyszek <mknyszek@google.com> | 2021-08-23 17:27:40 +0000 |
|---|---|---|
| committer | Dmitri Shuralyov <dmitshur@golang.org> | 2021-12-22 22:05:22 +0000 |
| commit | 1242f430a94ade0f560dc218029b2c830f65e6a2 (patch) | |
| tree | 69bbe39310304185ac7b14448f8ebe7e8efd7121 /src/runtime/mpagealloc_64bit.go | |
| parent | 59f1a26262ce157c0d8d0b87858649b2a7f752c0 (diff) | |
| download | go-1242f430a94ade0f560dc218029b2c830f65e6a2.tar.xz | |
[release-branch.go1.17] runtime: set iOS addr space to 40 bits with incremental pagealloc
In iOS <14, the address space is strictly limited to 8 GiB, or 33 bits.
As a result, the page allocator also assumes all heap memory lives in
this region. This is especially necessary because the page allocator has
a PROT_NONE mapping proportional to the size of the usable address
space, so this keeps that mapping very small.
However starting with iOS 14, this restriction is relaxed, and mmap may
start returning addresses outside of the <14 range. Today this means
that in iOS 14 and later, users experience an error in the page
allocator when a heap arena is mapped outside of the old range.
This change increases the ios/arm64 heapAddrBits to 40 while
simultaneously making ios/arm64 use the 64-bit pagealloc implementation
(with reservations and incremental mapping) to accommodate both iOS
versions <14 and 14+.
Once iOS <14 is deprecated, we can remove these exceptions and treat
ios/arm64 like any other arm64 platform.
This change also makes the BaseChunkIdx expression a little bit easier
to read, while we're here.
For #46860.
Fixes #48116.
Change-Id: I13865f799777739109585f14f1cc49d6d57e096b
Reviewed-on: https://go-review.googlesource.com/c/go/+/344401
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Austin Clements <austin@google.com>
(cherry picked from commit af368da0b137116faba81ca249a8d964297e6e45)
Reviewed-on: https://go-review.googlesource.com/c/go/+/369737
Diffstat (limited to 'src/runtime/mpagealloc_64bit.go')
| -rw-r--r-- | src/runtime/mpagealloc_64bit.go | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/src/runtime/mpagealloc_64bit.go b/src/runtime/mpagealloc_64bit.go index 16577346a7..8b72c25ffa 100644 --- a/src/runtime/mpagealloc_64bit.go +++ b/src/runtime/mpagealloc_64bit.go @@ -2,10 +2,8 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. -//go:build amd64 || (!ios && arm64) || mips64 || mips64le || ppc64 || ppc64le || riscv64 || s390x -// +build amd64 !ios,arm64 mips64 mips64le ppc64 ppc64le riscv64 s390x - -// See mpagealloc_32bit.go for why ios/arm64 is excluded here. +//go:build amd64 || arm64 || mips64 || mips64le || ppc64 || ppc64le || riscv64 || s390x +// +build amd64 arm64 mips64 mips64le ppc64 ppc64le riscv64 s390x package runtime |