From: Frederic Weisbecker Date: Thu, 17 Dec 2009 04:40:34 +0000 (+0100) Subject: perf events, x86/stacktrace: Fix performance/softlockup by providing a special frame... X-Git-Tag: v2.6.33-rc2~46^2~3 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=06d65bda75341485d32f33da474b0664819ad497;p=pandora-kernel.git perf events, x86/stacktrace: Fix performance/softlockup by providing a special frame pointer-only stack walker It's just wasteful for stacktrace users like perf to walk through every entries on the stack whereas these only accept reliable ones, ie: that the frame pointer validates. Since perf requires pure reliable stacktraces, it needs a stack walker based on frame pointers-only to optimize the stacktrace processing. This might solve some near-lockup scenarios that can be triggered by call-graph tracing timer events. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Paul Mackerras LKML-Reference: <1261024834-5336-2-git-send-regression-fweisbec@gmail.com> [ v2: fix for modular builds and small detail tidyup ] Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed