bcache: Fix/revamp tracepoints
The tracepoints were reworked to be more sensible, and fixed a null
pointer deref in one of the tracepoints.
Converted some of the pr_debug()s to tracepoints - this is partly a
performance optimization; it used to be that with DEBUG or
CONFIG_DYNAMIC_DEBUG pr_debug() was an empty macro; but at some point it
was changed to an empty inline function.
Some of the pr_debug() statements had rather expensive function calls as
part of the arguments, so this code was getting run unnecessarily even
on non debug kernels - in some fast paths, too.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 2714ed3..82f6d45 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -10,6 +10,8 @@
#include "btree.h"
#include "debug.h"
+#include <trace/events/bcache.h>
+
static struct workqueue_struct *dirty_wq;
static void read_dirty(struct closure *);
@@ -236,10 +238,12 @@
for (i = 0; i < KEY_PTRS(&w->key); i++)
atomic_inc(&PTR_BUCKET(dc->disk.c, &w->key, i)->pin);
- pr_debug("clearing %s", pkey(&w->key));
bch_btree_insert(&op, dc->disk.c);
closure_sync(&op.cl);
+ if (op.insert_collision)
+ trace_bcache_writeback_collision(&w->key);
+
atomic_long_inc(op.insert_collision
? &dc->disk.c->writeback_keys_failed
: &dc->disk.c->writeback_keys_done);
@@ -275,7 +279,6 @@
io->bio.bi_bdev = io->dc->bdev;
io->bio.bi_end_io = dirty_endio;
- trace_bcache_write_dirty(&io->bio);
closure_bio_submit(&io->bio, cl, &io->dc->disk);
continue_at(cl, write_dirty_finish, dirty_wq);
@@ -296,7 +299,6 @@
{
struct dirty_io *io = container_of(cl, struct dirty_io, cl);
- trace_bcache_read_dirty(&io->bio);
closure_bio_submit(&io->bio, cl, &io->dc->disk);
continue_at(cl, write_dirty, dirty_wq);
@@ -352,7 +354,7 @@
if (bch_bio_alloc_pages(&io->bio, GFP_KERNEL))
goto err_free;
- pr_debug("%s", pkey(&w->key));
+ trace_bcache_writeback(&w->key);
closure_call(&io->cl, read_dirty_submit, NULL, &dc->disk.cl);