On Sat, Jan 10, 2015 at 04:29:39AM +0100, Laszlo Ersek wrote: > I've bisected this issue to >
Awesome, this was on my list of list of suspicious commits to check before my ARM64 box decided not to come back from reboot on Friday. :) Thanks for bisecting! cheers, --Kyle > > f045bbb9fa1bf6f507ad4de12d4e3471d8f672f1 is the first bad commit > > commit f045bbb9fa1bf6f507ad4de12d4e3471d8f672f1 > > Author: Linus Torvalds <torva...@linux-foundation.org> > > Date: Wed Dec 17 11:59:04 2014 -0800 > > > > mmu_gather: fix over-eager tlb_flush_mmu_free() calling > > > > Dave Hansen reports that commit fb7332a9fedf ("mmu_gather: move minimal > > range calculations into generic code") caused a performance problem: > > > > "tlb_finish_mmu() goes up about 9x in the profiles (~0.4%->3.6%) and > > tlb_flush_mmu_free() takes about 3.1% of CPU time with the patch > > applied, but does not show up at all on the commit before" > > > > and the reason is that Will moved the test for whether we need to flush > > from tlb_flush_mmu() into tlb_flush_mmu_tlbonly(). But that meant that > > tlb_flush_mmu_free() basically lost that check. > > > > Move it back into tlb_flush_mmu() where it belongs, so that it covers > > both tlb_flush_mmu_tlbonly() _and_ tlb_flush_mmu_free(). > > > > Reported-and-tested-by: Dave Hansen <d...@sr71.net> > > Acked-by: Will Deacon <will.dea...@arm.com> > > Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/