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authorSteven Rostedt <srostedt@redhat.com>2009-03-12 11:21:08 -0400
committerSteven Rostedt <srostedt@redhat.com>2009-03-12 21:14:58 -0400
commita123c52b46a1f84bcec3dc963351896c6d6afaf7 (patch)
treebbfea12d2234930fd67644fa281d11c8ab850460
parent51b643b404827d8fde60d7953773a42d46ca87e0 (diff)
tracing: fix comments about trace buffer resizing
Impact: cleanup Some of the comments about the trace buffer resizing is gobbledygook. And I wonder why people question if I'm a native English speaker. This patch makes the comments make a bit more sense. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
-rw-r--r--kernel/trace/trace.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c3946a6df34e..c61ee85c50bb 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2336,7 +2336,8 @@ static int tracing_resize_ring_buffer(unsigned long size)
2336 2336
2337 /* 2337 /*
2338 * If kernel or user changes the size of the ring buffer 2338 * If kernel or user changes the size of the ring buffer
2339 * it get completed. 2339 * we use the size that was given, and we can forget about
2340 * expanding it later.
2340 */ 2341 */
2341 ring_buffer_expanded = 1; 2342 ring_buffer_expanded = 1;
2342 2343
@@ -2351,8 +2352,20 @@ static int tracing_resize_ring_buffer(unsigned long size)
2351 r = ring_buffer_resize(global_trace.buffer, 2352 r = ring_buffer_resize(global_trace.buffer,
2352 global_trace.entries); 2353 global_trace.entries);
2353 if (r < 0) { 2354 if (r < 0) {
2354 /* AARGH! We are left with different 2355 /*
2355 * size max buffer!!!! */ 2356 * AARGH! We are left with different
2357 * size max buffer!!!!
2358 * The max buffer is our "snapshot" buffer.
2359 * When a tracer needs a snapshot (one of the
2360 * latency tracers), it swaps the max buffer
2361 * with the saved snap shot. We succeeded to
2362 * update the size of the main buffer, but failed to
2363 * update the size of the max buffer. But when we tried
2364 * to reset the main buffer to the original size, we
2365 * failed there too. This is very unlikely to
2366 * happen, but if it does, warn and kill all
2367 * tracing.
2368 */
2356 WARN_ON(1); 2369 WARN_ON(1);
2357 tracing_disabled = 1; 2370 tracing_disabled = 1;
2358 } 2371 }