path: root/include/linux/sem.h
diff options
authorManfred Spraul <manfred@colorfullife.com>2009-12-15 16:47:32 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 07:20:10 -0800
commitb97e820ffffbf49e94ed60c9c26f1a54bccae924 (patch)
tree195146c43d24051aada20a211f2bb146bfebe9d2 /include/linux/sem.h
parentb6e90822e77cd476c18410f7003197d466e36ac6 (diff)
ipc/sem.c: add a per-semaphore pending list
Based on Nick's findings: sysv sem has the concept of semaphore arrays that consist out of multiple semaphores. Atomic operations that affect multiple semaphores are supported. The patch is the first step for optimizing simple, single semaphore operations: In addition to the global list of all pending operations, a 2nd, per-semaphore list with the simple operations is added. Note: this patch does not make sense by itself, the new list is used nowhere. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/sem.h')
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/sem.h b/include/linux/sem.h
index 1b191c176bc..8a4adbef8a0 100644
--- a/include/linux/sem.h
+++ b/include/linux/sem.h
@@ -86,6 +86,7 @@ struct task_struct;
struct sem {
int semval; /* current value */
int sempid; /* pid of last operation */
+ struct list_head sem_pending; /* pending single-sop operations */
/* One sem_array data structure for each set of semaphores in the system. */
@@ -96,11 +97,13 @@ struct sem_array {
struct sem *sem_base; /* ptr to first semaphore in array */
struct list_head sem_pending; /* pending operations to be processed */
struct list_head list_id; /* undo requests on this array */
- unsigned long sem_nsems; /* no. of semaphores in array */
+ int sem_nsems; /* no. of semaphores in array */
+ int complex_count; /* pending complex operations */
/* One queue for each sleeping process in the system. */
struct sem_queue {
+ struct list_head simple_list; /* queue of pending operations */
struct list_head list; /* queue of pending operations */
struct task_struct *sleeper; /* this process */
struct sem_undo *undo; /* undo structure */