From: Oleg Nesterov Date: Mon, 19 Mar 2012 16:03:22 +0000 (+0100) Subject: exit_signal: simplify the "we have changed execution domain" logic X-Git-Tag: v3.4-rc1~182 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e636825346b36a07ccfc8e30946d52855e21f681;p=pandora-kernel.git exit_signal: simplify the "we have changed execution domain" logic exit_notify() checks "tsk->self_exec_id != tsk->parent_exec_id" to handle the "we have changed execution domain" case. We can change do_thread() to always set ->exit_signal = SIGCHLD and remove this check to simplify the code. We could change setup_new_exec() instead, this looks more logical because it increments ->self_exec_id. But note that de_thread() already resets ->exit_signal if it changes the leader, let's keep both changes close to each other. Note that we change ->exit_signal lockless, this changes the rules. Thereafter ->exit_signal is not stable under tasklist but this is fine, the only possible change is OLDSIG -> SIGCHLD. This can race with eligible_child() but the race is harmless. We can race with reparent_leader() which changes our ->exit_signal in parallel, but it does the same change to SIGCHLD. The noticeable user-visible change is that the execing task is not "visible" to do_wait()->eligible_child(__WCLONE) right after exec. To me this looks more logical, and this is consistent with mt case. Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed