On Mon, 15 Feb 2010 16:14:22 -0800 (PST) David Rientjes <rientjes@xxxxxxxxxx> wrote: > On Tue, 16 Feb 2010, KAMEZAWA Hiroyuki wrote: > > > > If /proc/sys/vm/panic_on_oom is set to 2, the kernel will panic > > > regardless of whether the memory allocation is constrained by either a > > > mempolicy or cpuset. > > > > > > Since mempolicy-constrained out of memory conditions now iterate through > > > the tasklist and select a task to kill, it is possible to panic the > > > machine if all tasks sharing the same mempolicy nodes (including those > > > with default policy, they may allocate anywhere) or cpuset mems have > > > /proc/pid/oom_adj values of OOM_DISABLE. This is functionally equivalent > > > to the compulsory panic_on_oom setting of 2, so the mode is removed. > > > > > > Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> > > > > NACK. In an enviroment which depends on cluster-fail-over, this is useful > > even if in such situation. > > > > You don't understand that the behavior has changed ever since > mempolicy-constrained oom conditions are now affected by a compulsory > panic_on_oom mode, please see the patch description. It's absolutely > insane for a single sysctl mode to panic the machine anytime a cpuset or > mempolicy runs out of memory and is more prone to user error from setting > it without fully understanding the ramifications than any use it will ever > do. The kernel already provides a mechanism for doing this, OOM_DISABLE. > if you want your cpuset or mempolicy to risk panicking the machine, set > all tasks that share its mems or nodes, respectively, to OOM_DISABLE. > This is no different from the memory controller being immune to such > panic_on_oom conditions, stop believing that it is the only mechanism used > in the kernel to do memory isolation. > You don't explain why "we _have to_ remove API which is used" Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>