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authorRickard Green <[email protected]>2018-04-13 14:33:38 +0200
committerRickard Green <[email protected]>2018-05-16 13:28:46 +0200
commit78f639da759cd3f8b5f28bc86ec404f3c3db60f4 (patch)
tree1e449df42cf4bd3e840a10de105a4646d19136e9 /erts/doc/src/erlang.xml
parent08873ec673ef223a4e0c9826b0370d80bb6aad24 (diff)
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New process suspend implementation based on async signaling
Diffstat (limited to 'erts/doc/src/erlang.xml')
-rw-r--r--erts/doc/src/erlang.xml46
1 files changed, 45 insertions, 1 deletions
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 3154fdaf8c..cff56b9cb8 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -7005,10 +7005,47 @@ ok
from other events in the system. It is only guaranteed that
<c><anno>Suspendee</anno></c> <em>eventually</em> suspends
(unless it
- is resumed). If option <c>asynchronous</c> has <em>not</em>
+ is resumed). If no <c>asynchronous</c> options has
been passed, the caller of <c>erlang:suspend_process/2</c> is
blocked until <c><anno>Suspendee</anno></c> has suspended.</p>
</item>
+ <tag><c>{asynchronous, ReplyTag}</c></tag>
+ <item>
+ <p>A suspend request is sent to the process identified by
+ <c><anno>Suspendee</anno></c>. When the suspend request
+ has been processed, a reply message is sent to the caller
+ of this function. The reply is on the form <c>{ReplyTag,
+ State}</c> where <c>State</c> is either:</p>
+ <taglist>
+ <tag><c>exited</c></tag>
+ <item>
+ <p>
+ <c><anno>Suspendee</anno></c> has exited.
+ </p>
+ </item>
+ <tag><c>suspended</c></tag>
+ <item>
+ <p>
+ <c><anno>Suspendee</anno></c> is now suspended.
+ </p>
+ </item>
+ <tag><c>not_suspended</c></tag>
+ <item>
+ <p>
+ <c><anno>Suspendee</anno></c> is not suspended.
+ This can only happen when the process that
+ issued this request, have called
+ <c>resume_process(<anno>Suspendee</anno>)</c>
+ before getting the reply.
+ </p>
+ </item>
+ </taglist>
+ <p>
+ Appart from the reply message, the <c>{asynchronous,
+ ReplyTag}</c> option behaves exactly the same as the
+ <c>asynchronous</c> option without reply tag.
+ </p>
+ </item>
<tag><c>unless_suspending</c></tag>
<item>
<p>The process identified by <c><anno>Suspendee</anno></c> is
@@ -7032,6 +7069,13 @@ ok
<warning>
<p>This BIF is intended for debugging only.</p>
</warning>
+ <warning>
+ <p>You can easily create deadlocks if processes suspends
+ each other (directly or in circles). In ERTS versions prior
+ to ERTS version 10.0, the runtime system prevented such
+ deadlocks, but this prevention has now been removed due
+ to performance reasons.</p>
+ </warning>
<p>Failures:</p>
<taglist>
<tag><c>badarg</c></tag>