-
Notifications
You must be signed in to change notification settings - Fork 17.9k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
runtime: use MADV_FREE_REUSABLE on darwin
Currently on darwin we use MADV_FREE, which unfortunately doesn't result in a change in the process's RSS until pages actually get kicked out, which the OS is free to do lazily (e.g. until it finds itself under memory pressure). To remedy this, we instead use MADV_FREE_REUSABLE which has similar semantics, except that it also sets a reusable bit on each page so the process's RSS gets reported more accurately. The one caveat is for every time we call MADV_FREE_REUSABLE on a region we must call MADV_FREE_REUSE to keep the kernel's accounting updated. Also, because this change requires adding new constants that only exist on darwin, it splits mem_bsd.go into mem_bsd.go and mem_darwin.go. Fixes #29844. Change-Id: Idb6421698511138a430807bcbbd1516cd57557c8 Reviewed-on: https://go-review.googlesource.com/c/go/+/159117 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
- Loading branch information
Showing
7 changed files
with
102 additions
and
24 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,80 @@ | ||
| // Copyright 2018 The Go Authors. All rights reserved. | ||
| // Use of this source code is governed by a BSD-style | ||
| // license that can be found in the LICENSE file. | ||
|
|
||
| package runtime | ||
|
|
||
| import ( | ||
| "unsafe" | ||
| ) | ||
|
|
||
| // Don't split the stack as this function may be invoked without a valid G, | ||
| // which prevents us from allocating more stack. | ||
| //go:nosplit | ||
| func sysAlloc(n uintptr, sysStat *uint64) unsafe.Pointer { | ||
| v, err := mmap(nil, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_PRIVATE, -1, 0) | ||
| if err != 0 { | ||
| return nil | ||
| } | ||
| mSysStatInc(sysStat, n) | ||
| return v | ||
| } | ||
|
|
||
| func sysUnused(v unsafe.Pointer, n uintptr) { | ||
| // MADV_FREE_REUSABLE is like MADV_FREE except it also propagates | ||
| // accounting information about the process to task_info. | ||
| madvise(v, n, _MADV_FREE_REUSABLE) | ||
| } | ||
|
|
||
| func sysUsed(v unsafe.Pointer, n uintptr) { | ||
| // MADV_FREE_REUSE is necessary to keep the kernel's accounting | ||
| // accurate. If called on any memory region that hasn't been | ||
| // MADV_FREE_REUSABLE'd, it's a no-op. | ||
| madvise(v, n, _MADV_FREE_REUSE) | ||
| } | ||
|
|
||
| // Don't split the stack as this function may be invoked without a valid G, | ||
| // which prevents us from allocating more stack. | ||
| //go:nosplit | ||
| func sysFree(v unsafe.Pointer, n uintptr, sysStat *uint64) { | ||
| mSysStatDec(sysStat, n) | ||
| munmap(v, n) | ||
| } | ||
|
|
||
| func sysFault(v unsafe.Pointer, n uintptr) { | ||
| mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE|_MAP_FIXED, -1, 0) | ||
| } | ||
|
|
||
| func sysReserve(v unsafe.Pointer, n uintptr) unsafe.Pointer { | ||
| flags := int32(_MAP_ANON | _MAP_PRIVATE) | ||
| if raceenabled { | ||
| // Currently the race detector expects memory to live within a certain | ||
| // range, and on Darwin 10.10 mmap is prone to ignoring hints, moreso | ||
| // than later versions and other BSDs (#26475). So, even though it's | ||
| // potentially dangerous to MAP_FIXED, we do it in the race detection | ||
| // case because it'll help maintain the race detector's invariants. | ||
| // | ||
| // TODO(mknyszek): Drop this once support for Darwin 10.10 is dropped, | ||
| // and reconsider this when #24133 is addressed. | ||
| flags |= _MAP_FIXED | ||
| } | ||
| p, err := mmap(v, n, _PROT_NONE, flags, -1, 0) | ||
| if err != 0 { | ||
| return nil | ||
| } | ||
| return p | ||
| } | ||
|
|
||
| const _ENOMEM = 12 | ||
|
|
||
| func sysMap(v unsafe.Pointer, n uintptr, sysStat *uint64) { | ||
| mSysStatInc(sysStat, n) | ||
|
|
||
| p, err := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0) | ||
| if err == _ENOMEM { | ||
| throw("runtime: out of memory") | ||
| } | ||
| if p != v || err != 0 { | ||
| throw("runtime: cannot map pages in arena address space") | ||
| } | ||
| } |