From: chai wen Date: Thu, 9 Oct 2014 22:25:17 +0000 (-0700) Subject: softlockup: make detector be aware of task switch of processes hogging cpu X-Git-Tag: fixes-against-v3.18-rc2~137^2~141 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b1a8de1f534337b398c7778578a56ec4f018cb27;p=pandora-kernel.git softlockup: make detector be aware of task switch of processes hogging cpu For now, soft lockup detector warns once for each case of process softlockup. But the thread 'watchdog/n' may not always get the cpu at the time slot between the task switch of two processes hogging that cpu to reset soft_watchdog_warn. An example would be two processes hogging the cpu. Process A causes the softlockup warning and is killed manually by a user. Process B immediately becomes the new process hogging the cpu preventing the softlockup code from resetting the soft_watchdog_warn variable. This case is a false negative of "warn only once for a process", as there may be a different process that is going to hog the cpu. Resolve this by saving/checking the task pointer of the hogging process and use that to reset soft_watchdog_warn too. [dzickus@redhat.com: update comment] Signed-off-by: chai wen Signed-off-by: Don Zickus Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed