Make the semaphore undo code use a task watcher instead of hooking into copy_process() and do_exit() directly. Signed-off-by: Matt Helsley --- include/linux/sem.h | 17 ----------------- ipc/sem.c | 12 ++++++++---- kernel/exit.c | 3 --- kernel/fork.c | 6 +----- 4 files changed, 9 insertions(+), 29 deletions(-) Benchmark results: System: 4 1.7GHz ppc64 (Power 4+) processors, 30968600MB RAM, 2.6.19-rc2-mm2 kernel Clone Number of Children Cloned 5000 7500 10000 12500 15000 17500 --------------------------------------------------------------------------------------- Mean 17960.5 18169.3 18408.2 18479.9 18515.6 18465.4 Dev 305.381 314.209 292.395 284.992 299.331 295.311 Err (%) 1.70029 1.72934 1.5884 1.54217 1.61664 1.59927 Fork Number of Children Forked 5000 7500 10000 12500 15000 17500 --------------------------------------------------------------------------------------- Mean 18050.2 18141.4 18316.2 18386.2 18441.9 18476.2 Dev 295.68 312.922 296.962 298.81 300.985 294.046 Err (%) 1.63809 1.72491 1.62131 1.62519 1.63207 1.59149 Kernbench: Elapsed: 124.272s User: 439.643s System: 46.32s CPU: 390.5% 439.64user 46.25system 2:04.46elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k 439.70user 46.27system 2:04.04elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k 439.64user 46.31system 2:04.18elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k 439.49user 46.27system 2:04.41elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k 439.55user 46.47system 2:04.32elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k 439.77user 46.29system 2:04.63elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k 439.61user 46.31system 2:04.09elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k 439.68user 46.31system 2:04.02elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k 439.76user 46.49system 2:04.59elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k 439.59user 46.23system 2:03.98elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k Index: linux-2.6.19-rc2-mm2/ipc/sem.c =================================================================== --- linux-2.6.19-rc2-mm2.orig/ipc/sem.c +++ linux-2.6.19-rc2-mm2/ipc/sem.c @@ -81,10 +81,11 @@ #include #include #include #include #include +#include #include #include "util.h" #define sem_ids(ns) (*((ns)->ids[IPC_SEM_IDS])) @@ -1288,11 +1289,11 @@ asmlinkage long sys_semop (int semid, st * See the notes above unlock_semundo() regarding the spin_lock_init() * in this code. Initialize the undo_list->lock here instead of get_undo_list() * because of the reasoning in the comment above unlock_semundo. */ -int copy_semundo(unsigned long clone_flags, struct task_struct *tsk) +static int copy_semundo(unsigned long clone_flags, struct task_struct *tsk) { struct sem_undo_list *undo_list; int error; if (clone_flags & CLONE_SYSVSEM) { @@ -1304,10 +1305,11 @@ int copy_semundo(unsigned long clone_fla } else tsk->sysvsem.undo_list = NULL; return 0; } +task_watcher_func(init, copy_semundo); /* * add semadj values to semaphores, free undo structures. * undo structures are not freed when semaphore arrays are destroyed * so some of them may be out of date. @@ -1317,22 +1319,22 @@ int copy_semundo(unsigned long clone_fla * should we queue up and wait until we can do so legally? * The original implementation attempted to do this (queue and wait). * The current implementation does not do so. The POSIX standard * and SVID should be consulted to determine what behavior is mandated. */ -void exit_sem(struct task_struct *tsk) +static int exit_sem(unsigned long ignored, struct task_struct *tsk) { struct sem_undo_list *undo_list; struct sem_undo *u, **up; struct ipc_namespace *ns; undo_list = tsk->sysvsem.undo_list; if (!undo_list) - return; + return 0; if (!atomic_dec_and_test(&undo_list->refcnt)) - return; + return 0; ns = tsk->nsproxy->ipc_ns; /* There's no need to hold the semundo list lock, as current * is the last task exiting for this undo list. */ @@ -1395,11 +1397,13 @@ found: update_queue(sma); next_entry: sem_unlock(sma); } kfree(undo_list); + return 0; } +task_watcher_func(free, exit_sem); #ifdef CONFIG_PROC_FS static int sysvipc_sem_proc_show(struct seq_file *s, void *it) { struct sem_array *sma = it; Index: linux-2.6.19-rc2-mm2/kernel/exit.c =================================================================== --- linux-2.6.19-rc2-mm2.orig/kernel/exit.c +++ linux-2.6.19-rc2-mm2/kernel/exit.c @@ -46,12 +46,10 @@ #include #include #include #include -extern void sem_exit (void); - static void exit_mm(struct task_struct * tsk); static void __unhash_process(struct task_struct *p) { nr_threads--; @@ -919,11 +917,10 @@ fastcall NORET_TYPE void do_exit(long co exit_mm(tsk); notify_task_watchers(WATCH_TASK_FREE, code, tsk); if (group_dead) acct_process(); - exit_sem(tsk); __exit_files(tsk); __exit_fs(tsk); exit_thread(); cpuset_exit(tsk); exit_keys(tsk); Index: linux-2.6.19-rc2-mm2/kernel/fork.c =================================================================== --- linux-2.6.19-rc2-mm2.orig/kernel/fork.c +++ linux-2.6.19-rc2-mm2/kernel/fork.c @@ -1095,14 +1095,12 @@ static struct task_struct *copy_process( #endif if ((retval = security_task_alloc(p))) goto bad_fork_cleanup_policy; /* copy all the process information */ - if ((retval = copy_semundo(clone_flags, p))) - goto bad_fork_cleanup_security; if ((retval = copy_files(clone_flags, p))) - goto bad_fork_cleanup_semundo; + goto bad_fork_cleanup_security; if ((retval = copy_fs(clone_flags, p))) goto bad_fork_cleanup_files; if ((retval = copy_sighand(clone_flags, p))) goto bad_fork_cleanup_fs; if ((retval = copy_signal(clone_flags, p))) @@ -1269,12 +1267,10 @@ bad_fork_cleanup_sighand: __cleanup_sighand(p->sighand); bad_fork_cleanup_fs: exit_fs(p); /* blocking */ bad_fork_cleanup_files: exit_files(p); /* blocking */ -bad_fork_cleanup_semundo: - exit_sem(p); bad_fork_cleanup_security: security_task_free(p); bad_fork_cleanup_policy: #ifdef CONFIG_NUMA mpol_free(p->mempolicy); Index: linux-2.6.19-rc2-mm2/include/linux/sem.h =================================================================== --- linux-2.6.19-rc2-mm2.orig/include/linux/sem.h +++ linux-2.6.19-rc2-mm2/include/linux/sem.h @@ -136,25 +136,8 @@ struct sem_undo_list { struct sysv_sem { struct sem_undo_list *undo_list; }; -#ifdef CONFIG_SYSVIPC - -extern int copy_semundo(unsigned long clone_flags, struct task_struct *tsk); -extern void exit_sem(struct task_struct *tsk); - -#else -static inline int copy_semundo(unsigned long clone_flags, struct task_struct *tsk) -{ - return 0; -} - -static inline void exit_sem(struct task_struct *tsk) -{ - return; -} -#endif - #endif /* __KERNEL__ */ #endif /* _LINUX_SEM_H */ -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/