From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> To: Shawn Landden <slandden@gmail.com> Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC] EPOLL_KILLME: New flag to epoll_wait() that subscribes process to death row (new syscall) Date: Thu, 2 Nov 2017 07:10:24 +0900 [thread overview] Message-ID: <b98ae797-ce25-79bd-e405-35565256f673@I-love.SAKURA.ne.jp> (raw) In-Reply-To: <20171101053244.5218-1-slandden@gmail.com> On 2017/11/01 14:32, Shawn Landden wrote: > @@ -1029,6 +1030,22 @@ bool out_of_memory(struct oom_control *oc) > return true; > } > > + /* > + * Check death row. > + */ > + if (!list_empty(eventpoll_deathrow_list())) { > + struct list_head *l = eventpoll_deathrow_list(); Unsafe traversal. List can become empty at this moment. > + struct task_struct *ts = list_first_entry(l, > + struct task_struct, se.deathrow); > + > + pr_debug("Killing pid %u from EPOLL_KILLME death row.", > + ts->pid); > + > + /* We use SIGKILL so as to cleanly interrupt ep_poll() */ > + kill_pid(task_pid(ts), SIGKILL, 1); send_sig() ? > + return true; > + } > + > /* > * The OOM killer does not compensate for IO-less reclaim. > * pagefault_out_of_memory lost its gfp context so we have to > And why is static int oom_fd = open("/proc/self/oom_score_adj", O_WRONLY); and then toggling between write(fd, "1000", 4); and write(fd, "0", 1); not sufficient? Adding prctl() that do this might be handy though.
WARNING: multiple messages have this Message-ID (diff)
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> To: Shawn Landden <slandden@gmail.com> Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC] EPOLL_KILLME: New flag to epoll_wait() that subscribes process to death row (new syscall) Date: Thu, 2 Nov 2017 07:10:24 +0900 [thread overview] Message-ID: <b98ae797-ce25-79bd-e405-35565256f673@I-love.SAKURA.ne.jp> (raw) In-Reply-To: <20171101053244.5218-1-slandden@gmail.com> On 2017/11/01 14:32, Shawn Landden wrote: > @@ -1029,6 +1030,22 @@ bool out_of_memory(struct oom_control *oc) > return true; > } > > + /* > + * Check death row. > + */ > + if (!list_empty(eventpoll_deathrow_list())) { > + struct list_head *l = eventpoll_deathrow_list(); Unsafe traversal. List can become empty at this moment. > + struct task_struct *ts = list_first_entry(l, > + struct task_struct, se.deathrow); > + > + pr_debug("Killing pid %u from EPOLL_KILLME death row.", > + ts->pid); > + > + /* We use SIGKILL so as to cleanly interrupt ep_poll() */ > + kill_pid(task_pid(ts), SIGKILL, 1); send_sig() ? > + return true; > + } > + > /* > * The OOM killer does not compensate for IO-less reclaim. > * pagefault_out_of_memory lost its gfp context so we have to > And why is static int oom_fd = open("/proc/self/oom_score_adj", O_WRONLY); and then toggling between write(fd, "1000", 4); and write(fd, "0", 1); not sufficient? Adding prctl() that do this might be handy though. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-11-01 22:10 UTC|newest] Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-11-01 5:32 [RFC] EPOLL_KILLME: New flag to epoll_wait() that subscribes process to death row (new syscall) Shawn Landden 2017-11-01 5:32 ` Shawn Landden 2017-11-01 5:32 ` Shawn Landden 2017-11-01 14:04 ` Matthew Wilcox 2017-11-01 14:04 ` Matthew Wilcox 2017-11-01 15:16 ` Colin Walters 2017-11-01 15:16 ` Colin Walters 2017-11-01 15:22 ` Colin Walters 2017-11-01 15:22 ` Colin Walters 2017-11-03 9:22 ` peter enderborg 2017-11-03 9:22 ` peter enderborg 2017-11-03 9:22 ` peter enderborg 2017-11-01 19:02 ` Shawn Landden 2017-11-01 19:37 ` Colin Walters 2017-11-01 19:37 ` Colin Walters 2017-11-01 19:43 ` Shawn Landden 2017-11-01 20:54 ` Shawn Landden 2017-11-02 15:24 ` Shawn Paul Landden 2017-11-02 15:24 ` Shawn Paul Landden 2017-11-01 19:05 ` Shawn Landden 2017-11-01 22:10 ` Tetsuo Handa [this message] 2017-11-01 22:10 ` Tetsuo Handa 2017-11-02 7:36 ` Shawn Landden 2017-11-02 15:45 ` Michal Hocko 2017-11-02 15:45 ` Michal Hocko 2017-11-03 6:35 ` [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE_KILLME), for stateless idle loops Shawn Landden 2017-11-03 6:35 ` Shawn Landden 2017-11-03 6:35 ` Shawn Landden 2017-11-03 9:09 ` Michal Hocko 2017-11-03 9:09 ` Michal Hocko 2017-11-18 4:45 ` Shawn Landden 2017-11-19 4:19 ` Matthew Wilcox 2017-11-19 4:19 ` Matthew Wilcox 2017-11-19 4:19 ` Matthew Wilcox 2017-11-20 8:35 ` Michal Hocko 2017-11-20 8:35 ` Michal Hocko 2017-11-21 4:48 ` Shawn Landden 2017-11-21 4:48 ` Shawn Landden 2017-11-21 7:05 ` Michal Hocko 2017-11-21 7:05 ` Michal Hocko 2017-11-18 20:33 ` Shawn Landden 2017-11-18 20:33 ` Shawn Landden 2017-11-15 21:11 ` Pavel Machek 2017-11-21 4:49 ` [RFC v3] It is common for services to be stateless around their main event loop. If a process sets PR_SET_IDLE to PR_IDLE_MODE_KILLME then it signals to the kernel that epoll_wait() and friends may not complete, and the kernel may send SIGKILL if resources get tight Shawn Landden 2017-11-21 4:49 ` Shawn Landden 2017-11-21 4:49 ` Shawn Landden 2017-11-21 4:56 ` Shawn Landden 2017-11-21 4:56 ` Shawn Landden 2017-11-21 5:16 ` [RFC v4] " Shawn Landden 2017-11-21 5:16 ` Shawn Landden 2017-11-21 5:16 ` Shawn Landden 2017-11-21 5:26 ` Shawn Landden 2017-11-21 5:26 ` Shawn Landden 2017-11-21 9:14 ` Thomas Gleixner 2017-11-21 9:14 ` Thomas Gleixner 2017-11-22 10:29 ` [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE_KILLME), for stateless idle loops peter enderborg 2017-11-22 10:29 ` peter enderborg 2017-11-22 10:29 ` peter enderborg
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