|author||Peter Zijlstra <email@example.com>||2009-09-21 16:08:49 +0200|
|committer||Ingo Molnar <firstname.lastname@example.org>||2009-10-06 14:21:50 +0200|
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 <email@example.com> Acked-by: David Miller <firstname.lastname@example.org> Cc: Andrew Morton <email@example.com> Cc: Jens Axboe <firstname.lastname@example.org> Cc: Paul Mackerras <email@example.com> LKML-Reference: <1254830228.21044.272.camel@laptop> Signed-off-by: Ingo Molnar <firstname.lastname@example.org>
Diffstat (limited to 'tools/perf/design.txt')
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/design.txt b/tools/perf/design.txt
index f1946d107b10..fdd42a824c98 100644
@@ -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().