languages/dart-sdk
languages/dart-sdk
1
0
Fork 0
mirror of https://github.com/dart-lang/sdk synced 2024-10-14 15:57:17 +00:00
Code Issues Packages Projects Releases Wiki Activity

[vm] Update comment on thread interrupters.

Browse source 
TEST=docs only
Change-Id: Ib2921c485defc232264d0c4f86b783ce33c6eadd
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/302848
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
This commit is contained in:
Ryan Macnak 2023-05-11 21:41:01 +00:00 committed by Commit Queue
parent b8f28f576c
commit 4641a46077
1 changed files with 10 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
runtime/vm/thread_interrupter.cc
View file

@ -20,14 +20,16 @@ namespace dart {
// interrupted, the thread's interrupt callback is invoked. Callbacks cannot
// rely on being executed on the interrupted thread.
//
// There are two mechanisms used to interrupt a thread. The first, used on OSs
// with pthreads (Android, Linux, and Mac), is thread specific signal delivery.
// The second, used on Windows, is explicit suspend and resume thread system
// calls. Signal delivery forbids taking locks and allocating memory (which
// takes a lock). Explicit suspend and resume means that the interrupt callback
// will not be executing on the interrupted thread, making it meaningless to
// access TLS from within the thread interrupt callback. Combining these
// limitations, thread interrupt callbacks are forbidden from:
// There are two mechanisms used to interrupt a thread. The first, used on Linux
// and Android, is SIGPROF. The second, used on Windows, Fuchsia, Mac and iOS,
// is explicit suspend and resume thread system calls. (Although Mac supports
// SIGPROF, when the process is attached to lldb, it becomes unusably slow, and
// signal masking is unreliable across fork-exec.) Signal delivery forbids
// taking locks and allocating memory (which takes a lock). Explicit suspend and
// resume means that the interrupt callback will not be executing on the
// interrupted thread, making it meaningless to access TLS from within the
// thread interrupt callback. Combining these limitations, thread interrupt
// callbacks are forbidden from:
//
// * Accessing TLS.
// * Allocating memory.