提交 aceecc04 编写于 作者: O Oleg Nesterov 提交者: Linus Torvalds

[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: NOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
上级 2ceb8693
......@@ -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)) {
......
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