Commit f646e227b88a164a841d6b6dd969d8a45272dd83
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signal: retarget_shared_pending: consider shared/unblocked signals only
exit_signals() checks signal_pending() before retarget_shared_pending() but this is suboptimal. We can avoid the while_each_thread() loop in case when there are no shared signals visible to us. Add the "shared_pending.signal & ~blocked" check. We don't use tsk->blocked directly but pass ~blocked as an argument, this is needed for the next patch. Note: we can optimize this more. while_each_thread(t) can check t->blocked into account and stop after every pending signal has the new target, see the next patch. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com> Acked-by: Tejun Heo <tj@kernel.org>
Showing 1 changed file with 10 additions and 2 deletions Side-by-side Diff
kernel/signal.c
| ... | ... | @@ -2203,10 +2203,15 @@ |
| 2203 | 2203 | * group-wide signal. Another thread should be notified now to take |
| 2204 | 2204 | * the signal since we will not. |
| 2205 | 2205 | */ |
| 2206 | -static void retarget_shared_pending(struct task_struct *tsk) | |
| 2206 | +static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which) | |
| 2207 | 2207 | { |
| 2208 | + sigset_t retarget; | |
| 2208 | 2209 | struct task_struct *t; |
| 2209 | 2210 | |
| 2211 | + sigandsets(&retarget, &tsk->signal->shared_pending.signal, which); | |
| 2212 | + if (sigisemptyset(&retarget)) | |
| 2213 | + return; | |
| 2214 | + | |
| 2210 | 2215 | t = tsk; |
| 2211 | 2216 | while_each_thread(tsk, t) { |
| 2212 | 2217 | if (!signal_pending(t) && !(t->flags & PF_EXITING)) |
| ... | ... | @@ -2217,6 +2222,7 @@ |
| 2217 | 2222 | void exit_signals(struct task_struct *tsk) |
| 2218 | 2223 | { |
| 2219 | 2224 | int group_stop = 0; |
| 2225 | + sigset_t unblocked; | |
| 2220 | 2226 | |
| 2221 | 2227 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
| 2222 | 2228 | tsk->flags |= PF_EXITING; |
| ... | ... | @@ -2232,7 +2238,9 @@ |
| 2232 | 2238 | if (!signal_pending(tsk)) |
| 2233 | 2239 | goto out; |
| 2234 | 2240 | |
| 2235 | - retarget_shared_pending(tsk); | |
| 2241 | + unblocked = tsk->blocked; | |
| 2242 | + signotset(&unblocked); | |
| 2243 | + retarget_shared_pending(tsk, &unblocked); | |
| 2236 | 2244 | |
| 2237 | 2245 | if (unlikely(tsk->group_stop & GROUP_STOP_PENDING) && |
| 2238 | 2246 | task_participate_group_stop(tsk)) |