[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 <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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parent
2ceb8693ef
commit
aceecc0412
36
fs/exec.c
36
fs/exec.c
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@ -1368,6 +1368,22 @@ static void format_corename(char *corename, const char *pattern, long signr)
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*out_ptr = 0;
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}
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static void zap_process(struct task_struct *start, int *ptraced)
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{
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struct task_struct *t;
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t = start;
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do {
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if (t != current && t->mm) {
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t->mm->core_waiters++;
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force_sig_specific(SIGKILL, t);
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if (unlikely(t->ptrace) &&
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unlikely(t->parent->mm == t->mm))
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*ptraced = 1;
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}
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} while ((t = next_thread(t)) != start);
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}
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static void zap_threads (struct mm_struct *mm)
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{
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struct task_struct *g, *p;
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@ -1385,16 +1401,16 @@ static void zap_threads (struct mm_struct *mm)
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}
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read_lock(&tasklist_lock);
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do_each_thread(g,p)
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if (mm == p->mm && p != tsk) {
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force_sig_specific(SIGKILL, p);
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mm->core_waiters++;
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if (unlikely(p->ptrace) &&
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unlikely(p->parent->mm == mm))
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traced = 1;
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}
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while_each_thread(g,p);
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for_each_process(g) {
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p = g;
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do {
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if (p->mm) {
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if (p->mm == mm)
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zap_process(p, &traced);
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break;
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}
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} while ((p = next_thread(p)) != g);
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}
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read_unlock(&tasklist_lock);
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if (unlikely(traced)) {
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