From aceecc041217b35df753d1ed6e25bd17c0c558d8 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 26 Jun 2006 00:26:05 -0700 Subject: [PATCH] [PATCH] coredump: optimize ->mm users traversal 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" Acked-by: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/exec.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index fffea1eef8..80fe7bcfa0 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1368,6 +1368,22 @@ static void format_corename(char *corename, const char *pattern, long signr) *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; @@ -1385,16 +1401,16 @@ static void zap_threads (struct mm_struct *mm) } 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)) { -- 2.39.5