From: Paul E. McKenney Date: Wed, 18 Jun 2008 16:26:49 +0000 (-0700) Subject: rcu: make rcutorture more vicious: reinstate boot-time testing X-Git-Tag: v2.6.27-rc1~1070^2^2~7 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=31a72bce0bd6f3e0114009288bccbc96376eeeca;p=pandora-kernel.git rcu: make rcutorture more vicious: reinstate boot-time testing This patch re-institutes the ability to build rcutorture directly into the Linux kernel. The reason that this capability was removed was that this could result in your kernel being pretty much useless, as rcutorture would be running starting from early boot. This problem has been avoided by (1) making rcutorture run only three seconds of every six by default, (2) adding a CONFIG_RCU_TORTURE_TEST_RUNNABLE that permits rcutorture to be quiesced at boot time, and (3) adding a sysctl in /proc named /proc/sys/kernel/rcutorture_runnable that permits rcutorture to be quiesced and unquiesced when built into the kernel. Please note that this /proc file is -not- available when rcutorture is built as a module. Please also note that to get the earlier take-no-prisoners behavior, you must use the boot command line to set rcutorture's "stutter" parameter to zero. The rcutorture quiescing mechanism is currently quite crude: loops in each rcutorture process that poll a global variable once per tick. Suggestions for improvement are welcome. The default action will be to reduce the polling rate to a few times per second. Signed-off-by: Paul E. McKenney Suggested-by: Ingo Molnar Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed