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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-09-21 18:08:49 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-10-06 16:21:50 +0400 |
| commit | 906010b2134e14a2e377decbadd357b3d0ab9c6a (patch) | |
| tree | 598b30d08f5ca8df1e00abc295b120fa1bd2c2e2 /tools/perf/design.txt | |
| parent | e13dbd7d75d1ecc315c6e3071b3c4e8fba4f6bec (diff) | |
| download | linux-906010b2134e14a2e377decbadd357b3d0ab9c6a.tar.xz | |
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 <a.p.zijlstra@chello.nl>
Acked-by: David Miller <davem@davemloft.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1254830228.21044.272.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'tools/perf/design.txt')
| -rw-r--r-- | tools/perf/design.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/design.txt b/tools/perf/design.txt index f1946d107b10..fdd42a824c98 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(). |