The patch titled Subject: ipc: remove bogus lock comment for ipc_checkid has been removed from the -mm tree. Its filename was ipc-remove-bogus-lock-comment-for-ipc_checkid.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Davidlohr Bueso <davidlohr.bueso@xxxxxx> Subject: ipc: remove bogus lock comment for ipc_checkid This series makes the sysv semaphore code more scalable, by reducing the time the semaphore lock is held, and making the locking more scalable for semaphore arrays with multiple semaphores. The first four patches were written by Davidlohr Buesso, and reduce the hold time of the semaphore lock. The last three patches change the sysv semaphore code locking to be more fine grained, providing a performance boost when multiple semaphores in a semaphore array are being manipulated simultaneously. On a 24 CPU system, performance numbers with the semop-multi test with N threads and N semaphores, look like this: vanilla Davidlohr's Davidlohr's + Davidlohr's + threads patches rwlock patches v3 patches 10 610652 726325 1783589 2142206 20 341570 365699 1520453 1977878 30 288102 307037 1498167 2037995 40 290714 305955 1612665 2256484 50 288620 312890 1733453 2650292 60 289987 306043 1649360 2388008 70 291298 306347 1723167 2717486 80 290948 305662 1729545 2763582 90 290996 306680 1736021 2757524 100 292243 306700 1773700 3059159 This patch: There is no reason to be holding the ipc lock while reading ipcp->seq, hence remove misleading comment. Also simplify the return value for the function. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@xxxxxx> Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> Cc: Chegu Vinod <chegu_vinod@xxxxxx> Cc: Emmanuel Benisty <benisty.e@xxxxxxxxx> Cc: Jason Low <jason.low2@xxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Michel Lespinasse <walken@xxxxxxxxxx> Cc: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> Cc: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx> Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- ipc/util.h | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff -puN ipc/util.h~ipc-remove-bogus-lock-comment-for-ipc_checkid ipc/util.h --- a/ipc/util.h~ipc-remove-bogus-lock-comment-for-ipc_checkid +++ a/ipc/util.h @@ -150,14 +150,9 @@ static inline int ipc_buildid(int id, in return SEQ_MULTIPLIER * seq + id; } -/* - * Must be called with ipcp locked - */ static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) { - if (uid / SEQ_MULTIPLIER != ipcp->seq) - return 1; - return 0; + return uid / SEQ_MULTIPLIER != ipcp->seq; } static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm) _ Patches currently in -mm which might be from davidlohr.bueso@xxxxxx are origin.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html