Date: Sat, 24 Jan 2015 17:32:46 +0000 (UTC) From: Will Andrews <will@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r277651 - head/sys/vm Message-ID: <201501241732.t0OHWkD3089056@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: will Date: Sat Jan 24 17:32:45 2015 New Revision: 277651 URL: https://svnweb.freebsd.org/changeset/base/277651 Log: Add vm.panic_on_oom sysctl, which enables those who would rather panic than kill a process, when the system runs out of memory. Defaults to off. Usually, this is most useful when the OOM condition is due to mismanagement of memory, on a system where the applications in question don't respond well to being killed. In theory, if the system is properly managed, it shouldn't be possible to hit this condition. If it does, the panic can be more desirable for some users (since it can be a good means of finding the root cause) rather than killing the largest process and continuing on its merry way. As kib@ mentions in the differential, there is also protect(1), which uses procctl(PROC_SPROTECT) to ensure that some processes are immune. However, a panic approach is still useful in some environments. This is primarily intended as a development/debugging tool. Differential Revision: D1627 Reviewed by: kib MFC after: 1 week Modified: head/sys/vm/vm_pageout.c Modified: head/sys/vm/vm_pageout.c ============================================================================== --- head/sys/vm/vm_pageout.c Sat Jan 24 17:11:11 2015 (r277650) +++ head/sys/vm/vm_pageout.c Sat Jan 24 17:32:45 2015 (r277651) @@ -180,6 +180,12 @@ static int vm_swap_enabled = 1; static int vm_swap_idle_enabled = 0; #endif +static int vm_panic_on_oom = 0; + +SYSCTL_INT(_vm, OID_AUTO, panic_on_oom, + CTLFLAG_RWTUN, &vm_panic_on_oom, 0, + "panic on out of memory instead of killing the largest process"); + SYSCTL_INT(_vm, OID_AUTO, pageout_wakeup_thresh, CTLFLAG_RW, &vm_pageout_wakeup_thresh, 0, "free page threshold for waking up the pageout daemon"); @@ -1585,6 +1591,8 @@ vm_pageout_oom(int shortage) } sx_sunlock(&allproc_lock); if (bigproc != NULL) { + if (vm_panic_on_oom != 0) + panic("out of swap space"); PROC_LOCK(bigproc); killproc(bigproc, "out of swap space"); sched_nice(bigproc, PRIO_MIN);
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201501241732.t0OHWkD3089056>