From: Paul Mackerras Date: Wed, 9 Sep 2009 20:28:49 +0000 (+0000) Subject: powerpc/perf_counters: Reduce stack usage of power_check_constraints X-Git-Tag: v2.6.32-rc1~675^2~4 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e51ee31e8af22948dcc3b115978469b09c96c3fd;p=pandora-kernel.git powerpc/perf_counters: Reduce stack usage of power_check_constraints Michael Ellerman reported stack-frame size warnings being produced for power_check_constraints(), which uses an 8*8 array of u64 and two 8*8 arrays of unsigned long, which are currently allocated on the stack, along with some other smaller variables. These arrays come to 1.5kB on 64-bit or 1kB on 32-bit, which is a bit too much for the stack. This fixes the problem by putting these arrays in the existing per-cpu cpu_hw_counters struct. This is OK because two of the call sites have interrupts disabled already; for the third call site we use get_cpu_var, which disables preemption, so we know we won't get a context switch while we're in power_check_constraints(). Note that power_check_constraints() can be called during context switch but is not called from interrupts. Reported-by: Michael Ellerman Signed-off-by: Paul Mackerras Cc: --- Reading git-diff-tree failed