On Tue, Feb 02, 2016 at 10:33:22PM +0900, Tetsuo Handa wrote: > >From 20b3c1c9ef35547395c3774c6208a867cf0046d4 Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> > Date: Tue, 2 Feb 2016 16:50:45 +0900 > Subject: [RFC][PATCH] mm, page_alloc: Warn on !__GFP_NOWARN allocation from IRQ context. > > Jan Stancek hit a hard lockup problem due to flood of memory allocation > failure messages which lasted for 10 seconds with IRQ disabled. Printing > traces using warn_alloc_failed() is very slow (which can take up to about > 1 second for each warn_alloc_failed() call). The caller used GFP_NOWARN > inside a loop. If the caller used __GFP_NOWARN, it would not have lasted > for 10 seconds. Who is doing page allocations in a loop with irqs disabled?! And then, why does it take that long? Is that a serial console? Most of the output is KERN_INFO, it might be better to raise the loglevel and still have all the debugging output in the logs. If that's not enough, we could consider changing the ratelimit or make should_suppress_show_mem() filter interrupts regardless of NODES_SHIFT. Or ratelimit show_mem() in a different way than the single page alloc failure line. It's not that the state changes significantly while an avalanche of allocations are failing. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>