docs/132546: [patch] sync vm_map_lock(9) with recent locking changes

pluknet pluknet at gmail.com
Wed Mar 11 15:10:05 UTC 2009


>Number:         132546
>Category:       docs
>Synopsis:       [patch] sync vm_map_lock(9) with recent locking changes
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-doc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Mar 11 15:10:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     pluknet
>Release:        FreeBSD 8.0-CURRENT
>Organization:
RIPN
>Environment:
FreeBSD 8.0-CURRENT
>Description:
Quoting commit log to vm_map.c, v1.402:

"Resurrect shared map locks allowing greater concurrency during some map
operations, such as page faults.
[..]
MFC after:	6 weeks"

vm_map_lock(9) was not updated to reflect the reality.
>How-To-Repeat:

>Fix:
Apply the patch.



Patch attached with submission follows:

--- share/man/man9/vm_map_lock.9.orig	Wed Mar 11 17:57:55 2009
+++ share/man/man9/vm_map_lock.9	Wed Mar 11 17:59:54 2009
@@ -73,7 +73,6 @@
 .Fn vm_map_lock_read
 macro obtains a read-lock on
 .Fa map .
-Currently this is implemented as an exclusive lock.
 .Pp
 The
 .Fn vm_map_unlock_read
@@ -93,23 +92,18 @@
 .Fa map .
 It returns FALSE if the lock cannot be immediately acquired;
 otherwise return TRUE with the lock acquired.
-Currently this is implemented as an exclusive lock.
 .Pp
 The
 .Fn vm_map_lock_upgrade
 macro attempts to atomically upgrade a read-lock on
 .Fa map
 to an exclusive lock.
-As read-locks are currently implemented as exclusive locks,
-this macro is a no-op.
 .Pp
 The
 .Fn vm_map_lock_downgrade
 macro attempts to downgrade an exclusive lock on
 .Fa map
 to a read-lock.
-As read-locks are currently implemented as exclusive locks,
-this macro is a no-op.
 .Sh IMPLEMENTATION NOTES
 Currently, all of the locking macros implement their locks as sleep locks.
 .Sh SEE ALSO


>Release-Note:
>Audit-Trail:
>Unformatted:



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