Changeset c170438 in mainline for uspace/lib/c/generic/ipc.c

Timestamp:

2016-05-24T21:00:37Z (9 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

2a7ba5e

Parents:

f570cdf

Message:

Do not create a new fibril for each IRQ notification

In the absence of fibril serialization, manager fibrils can
theoretically block in async IPC or on fibril synchronization
primitives. Consequently, it is safe to execute the IRQ handler directly
from the manager fibril. The manager fibril can block while processing
the notification, but most of the times it will not block and the
handler will execute atomically.

This changeset modifies the current behaviour so that we no longer spawn
a new notification fibril for each IRQ, but rather execute the handler
directly from the manager fibril and test if the execution blocked. If
it blocked, the manager fibril had assumed the role of a notification
fibril and we destroy it afterwards - merely to avoid fibril population
explosion. Otherwise, which is the usual behavior, we keep it so that
it resumes its job of a manager fibril.

File:

• uspace/lib/c/generic/ipc.c (modified) (2 diffs)

uspace/lib/c/generic/ipc.c

@@ -96 +96 @@
 }
 
-/** Prolog for ipc_call_async_*() functions.
+/** Prologue for ipc_call_async_*() functions.
  *
  * @param private  Argument for the answer/error callback.
@@ -122 +122 @@
 }
 
-/** Epilog for ipc_call_async_*() functions.
+/** Epilogue for ipc_call_async_*() functions.
  *
  * @param callid      Value returned by the SYS_IPC_CALL_ASYNC_* syscall.