From: Oleg Nesterov zap_threads() iterates over all threads to find those ones which share current->mm. All threads in the thread group share the same ->mm, so we can skip entire thread group if it has another ->mm. This patch shifts the killing of thread group into the newly added zap_process() function. This looks as unnecessary complication, but it is used in further patches. Signed-off-by: Oleg Nesterov Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton --- fs/exec.c | 36 ++++++++++++++++++++++++++---------- 1 files changed, 26 insertions(+), 10 deletions(-) diff -puN fs/exec.c~coredump-optimize-mm-users-traversal fs/exec.c --- 25/fs/exec.c~coredump-optimize-mm-users-traversal Thu Apr 6 16:03:29 2006 +++ 25-akpm/fs/exec.c Thu Apr 6 16:03:29 2006 @@ -1386,6 +1386,22 @@ static void format_corename(char *corena *out_ptr = 0; } +static void zap_process(struct task_struct *start, int *ptraced) +{ + struct task_struct *t; + + t = start; + do { + if (t != current && t->mm) { + t->mm->core_waiters++; + force_sig_specific(SIGKILL, t); + if (unlikely(t->ptrace) && + unlikely(t->parent->mm == t->mm)) + *ptraced = 1; + } + } while ((t = next_thread(t)) != start); +} + static void zap_threads (struct mm_struct *mm) { struct task_struct *g, *p; @@ -1403,16 +1419,16 @@ static void zap_threads (struct mm_struc } read_lock(&tasklist_lock); - do_each_thread(g,p) - if (mm == p->mm && p != tsk) { - force_sig_specific(SIGKILL, p); - mm->core_waiters++; - if (unlikely(p->ptrace) && - unlikely(p->parent->mm == mm)) - traced = 1; - } - while_each_thread(g,p); - + for_each_process(g) { + p = g; + do { + if (p->mm) { + if (p->mm == mm) + zap_process(p, &traced); + break; + } + } while ((p = next_thread(p)) != g); + } read_unlock(&tasklist_lock); if (unlikely(traced)) { _