From 906010b2134e14a2e377decbadd357b3d0ab9c6a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 21 Sep 2009 16:08:49 +0200 Subject: perf_event: Provide vmalloc() based mmap() backing Some architectures such as Sparc, ARM and MIPS (basically everything with flush_dcache_page()) need to deal with dcache aliases by carefully placing pages in both kernel and user maps. These architectures typically have to use vmalloc_user() for this. However, on other architectures, vmalloc() is not needed and has the downsides of being more restricted and slower than regular allocations. Signed-off-by: Peter Zijlstra Acked-by: David Miller Cc: Andrew Morton Cc: Jens Axboe Cc: Paul Mackerras LKML-Reference: <1254830228.21044.272.camel@laptop> Signed-off-by: Ingo Molnar --- tools/perf/design.txt | 3 +++ 1 file changed, 3 insertions(+) (limited to 'tools') diff --git a/tools/perf/design.txt b/tools/perf/design.txt index f1946d107b1..fdd42a824c9 100644 --- a/tools/perf/design.txt +++ b/tools/perf/design.txt @@ -455,3 +455,6 @@ will need at least this: If your architecture does have hardware capabilities, you can override the weak stub hw_perf_event_init() to register hardware counters. + +Architectures that have d-cache aliassing issues, such as Sparc and ARM, +should select PERF_USE_VMALLOC in order to avoid these for perf mmap(). -- cgit v1.2.3