From b483cf3bc249d7af706390efa63d6671e80d1c09 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 14 Oct 2017 09:26:59 +0200 Subject: [PATCH] locking/lockdep: Disable cross-release features for now Johan Hovold reported a big lockdep slowdown on his system, caused by lockdep: > I had noticed that the BeagleBone Black boot time appeared to have > increased significantly with 4.14 and yesterday I finally had time to > investigate it. > > Boot time (from "Linux version" to login prompt) had in fact doubled > since 4.13 where it took 17 seconds (with my current config) compared to > the 35 seconds I now see with 4.14-rc4. > > I quick bisect pointed to lockdep and specifically the following commit: > > 28a903f63ec0 ("locking/lockdep: Handle non(or multi)-acquisition of a crosslock") Because the final v4.14 release is close, disable the cross-release lockdep features for now. Bisected-by: Johan Hovold Debugged-by: Johan Hovold Reported-by: Johan Hovold Cc: Arnd Bergmann Cc: Byungchul Park Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Lindgren Cc: kernel-team@lge.com Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mm@kvack.org Cc: linux-omap@vger.kernel.org Link: http://lkml.kernel.org/r/20171014072659.f2yr6mhm5ha3eou7@gmail.com Signed-off-by: Ingo Molnar --- lib/Kconfig.debug | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 2689b7c50c529..e2705843c524d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1092,8 +1092,8 @@ config PROVE_LOCKING select DEBUG_MUTEXES select DEBUG_RT_MUTEXES if RT_MUTEXES select DEBUG_LOCK_ALLOC - select LOCKDEP_CROSSRELEASE - select LOCKDEP_COMPLETIONS + select LOCKDEP_CROSSRELEASE if BROKEN + select LOCKDEP_COMPLETIONS if BROKEN select TRACE_IRQFLAGS default n help -- 2.39.5