ed09e0e2bf
Currently, it's possible for the next_gc calculation to underflow. Since next_gc is unsigned, this wraps around and effectively disables GC for the rest of the program's execution. Besides being obviously wrong, this is causing test failures on 32-bit because some tests are running out of heap. This underflow happens for two reasons, both having to do with how we estimate the reachable heap size at the end of the GC cycle. One reason is that this calculation depends on the value of heap_live at the beginning of the GC cycle, but we currently only record that value during a concurrent GC and not during a forced STW GC. Fix this by moving the recorded value from gcController to work and recording it on a common code path. The other reason is that we use the amount of allocation during the GC cycle as an approximation of the amount of floating garbage and subtract it from the marked heap to estimate the reachable heap. However, since this is only an approximation, it's possible for the amount of allocation during the cycle to be *larger* than the marked heap size (since the runtime allocates white and it's possible for these allocations to never be made reachable from the heap). Currently this causes wrap-around in our estimate of the reachable heap size, which in turn causes wrap-around in next_gc. Fix this by bottoming out the reachable heap estimate at 0, in which case we just fall back to triggering GC at heapminimum (which is okay since this only happens on small heaps). Fixes #10555, fixes #10556, and fixes #10559. Change-Id: Iad07b529c03772356fede2ae557732f13ebfdb63 Reviewed-on: https://go-review.googlesource.com/9286 Run-TryBot: Austin Clements <austin@google.com> Reviewed-by: Rick Hudson <rlh@golang.org> |
||
|---|---|---|
| api | ||
| doc | ||
| lib/time | ||
| misc | ||
| src | ||
| test | ||
| .gitattributes | ||
| .gitignore | ||
| AUTHORS | ||
| CONTRIBUTING.md | ||
| CONTRIBUTORS | ||
| favicon.ico | ||
| LICENSE | ||
| PATENTS | ||
| README.md | ||
| robots.txt | ||
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.
Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.
Please report issues here: https://golang.org/issue/new
Go is the work of hundreds of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Please note that we do not use pull requests.
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
--
Binary Distribution Notes
If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:
export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin
See https://golang.org/doc/install or doc/install.html for more details.