[PATCH] trace: reorder struct ring_buffer_per_cpu to removepadding on 64bit

From: Richard Kennedy
Date: Thu Mar 25 2010 - 07:27:42 EST


Reorder structure to remove 8 bytes of padding on 64 bit builds.
This shrinks the size to 128 bytes so allowing allocation from a smaller
slab & needed one fewer cache lines.

Signed-off-by: Richard Kennedy <richard@xxxxxxxxxxxxxxx>
----
patch against 2.6.34-rc2
compiled & booted on x86_64

regards
Richard

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 05a9f83..421db5e 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -422,6 +422,7 @@ int ring_buffer_print_page_header(struct trace_seq
*s)
*/
struct ring_buffer_per_cpu {
int cpu;
+ atomic_t record_disabled;
struct ring_buffer *buffer;
spinlock_t reader_lock; /* serialize readers */
arch_spinlock_t lock;
@@ -439,7 +440,6 @@ struct ring_buffer_per_cpu {
unsigned long read;
u64 write_stamp;
u64 read_stamp;
- atomic_t record_disabled;
};

struct ring_buffer {


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