Commit c37511b8 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

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: default avatarKent Overstreet <koverstreet@google.com>
parent 57943511

drivers/md/bcache/alloc.c

+3 −7
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ 


#include <linux/kthread.h>

#include <linux/random.h>

#include <trace/events/bcache.h>



#define MAX_IN_FLIGHT_DISCARDS		8U
@@ -351,10 +352,7 @@ static void invalidate_buckets(struct cache *ca) 
		break;

	}



	pr_debug("free %zu/%zu free_inc %zu/%zu unused %zu/%zu",

		 fifo_used(&ca->free), ca->free.size,

		 fifo_used(&ca->free_inc), ca->free_inc.size,

		 fifo_used(&ca->unused), ca->unused.size);

	trace_bcache_alloc_invalidate(ca);

}



#define allocator_wait(ca, cond)					\
@@ -473,9 +471,7 @@ again: 
		return r;

	}



	pr_debug("alloc failure: blocked %i free %zu free_inc %zu unused %zu",

		 atomic_read(&ca->set->prio_blocked), fifo_used(&ca->free),

		 fifo_used(&ca->free_inc), fifo_used(&ca->unused));

	trace_bcache_alloc_fail(ca);



	if (cl) {

		closure_wait(&ca->set->bucket_wait, cl);

drivers/md/bcache/bcache.h

+0 −20
Original line number Diff line number Diff line
@@ -178,7 +178,6 @@ 
#define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__



#include <linux/bio.h>

#include <linux/blktrace_api.h>

#include <linux/kobject.h>

#include <linux/list.h>

#include <linux/mutex.h>
@@ -901,8 +900,6 @@ static inline unsigned local_clock_us(void) 
	return local_clock() >> 10;

}



#define MAX_BSETS		4U



#define BTREE_PRIO		USHRT_MAX

#define INITIAL_PRIO		32768
@@ -1107,23 +1104,6 @@ static inline void __bkey_put(struct cache_set *c, struct bkey *k) 
		atomic_dec_bug(&PTR_BUCKET(c, k, i)->pin);

}



/* Blktrace macros */



#define blktrace_msg(c, fmt, ...)					\

do {									\

	struct request_queue *q = bdev_get_queue(c->bdev);		\

	if (q)								\

		blk_add_trace_msg(q, fmt, ##__VA_ARGS__);		\

} while (0)



#define blktrace_msg_all(s, fmt, ...)					\

do {									\

	struct cache *_c;						\

	unsigned i;							\

	for_each_cache(_c, (s), i)					\

		blktrace_msg(_c, fmt, ##__VA_ARGS__);			\

} while (0)



static inline void cached_dev_put(struct cached_dev *dc)

{

	if (atomic_dec_and_test(&dc->count))

drivers/md/bcache/bset.h

+4 −0
Original line number Diff line number Diff line 
#ifndef _BCACHE_BSET_H

#define _BCACHE_BSET_H



#include <linux/slab.h>



/*

 * BKEYS:

 *
@@ -142,6 +144,8 @@ 


/* Btree key comparison/iteration */



#define MAX_BSETS		4U



struct btree_iter {

	size_t size, used;

	struct btree_iter_set {

drivers/md/bcache/btree.c

+24 −23
Original line number Diff line number Diff line
@@ -223,8 +223,9 @@ void bch_btree_node_read(struct btree *b) 
	struct closure cl;

	struct bio *bio;



	trace_bcache_btree_read(b);



	closure_init_stack(&cl);

	pr_debug("%s", pbtree(b));



	bio = bch_bbio_alloc(b->c);

	bio->bi_rw	= REQ_META|READ_SYNC;
@@ -234,7 +235,6 @@ void bch_btree_node_read(struct btree *b) 


	bch_bio_map(bio, b->sets[0].data);



	trace_bcache_btree_read(bio);

	bch_submit_bbio(bio, b->c, &b->key, 0);

	closure_sync(&cl);
@@ -343,7 +343,6 @@ static void do_btree_node_write(struct btree *b) 
			memcpy(page_address(bv->bv_page),

			       base + j * PAGE_SIZE, PAGE_SIZE);



		trace_bcache_btree_write(b->bio);

		bch_submit_bbio(b->bio, b->c, &k.key, 0);



		continue_at(cl, btree_node_write_done, NULL);
@@ -351,7 +350,6 @@ static void do_btree_node_write(struct btree *b) 
		b->bio->bi_vcnt = 0;

		bch_bio_map(b->bio, i);



		trace_bcache_btree_write(b->bio);

		bch_submit_bbio(b->bio, b->c, &k.key, 0);



		closure_sync(cl);
@@ -363,10 +361,13 @@ void bch_btree_node_write(struct btree *b, struct closure *parent) 
{

	struct bset *i = b->sets[b->nsets].data;



	trace_bcache_btree_write(b);



	BUG_ON(current->bio_list);

	BUG_ON(b->written >= btree_blocks(b));

	BUG_ON(b->written && !i->keys);

	BUG_ON(b->sets->data->seq != i->seq);

	bch_check_key_order(b, i);



	cancel_delayed_work(&b->work);
@@ -376,12 +377,8 @@ void bch_btree_node_write(struct btree *b, struct closure *parent) 
	clear_bit(BTREE_NODE_dirty,	 &b->flags);

	change_bit(BTREE_NODE_write_idx, &b->flags);



	bch_check_key_order(b, i);



	do_btree_node_write(b);



	pr_debug("%s block %i keys %i", pbtree(b), b->written, i->keys);



	b->written += set_blocks(i, b->c);

	atomic_long_add(set_blocks(i, b->c) * b->c->sb.block_size,

			&PTR_CACHE(b->c, &b->key, 0)->btree_sectors_written);
@@ -752,6 +749,8 @@ static struct btree *mca_cannibalize(struct cache_set *c, struct bkey *k, 
	int ret = -ENOMEM;

	struct btree *i;



	trace_bcache_btree_cache_cannibalize(c);



	if (!cl)

		return ERR_PTR(-ENOMEM);
@@ -770,7 +769,6 @@ static struct btree *mca_cannibalize(struct cache_set *c, struct bkey *k, 
		return ERR_PTR(-EAGAIN);

	}



	/* XXX: tracepoint */

	c->try_harder = cl;

	c->try_harder_start = local_clock();

retry:
@@ -956,13 +954,14 @@ static void btree_node_free(struct btree *b, struct btree_op *op) 
{

	unsigned i;



	trace_bcache_btree_node_free(b);



	/*

	 * The BUG_ON() in btree_node_get() implies that we must have a write

	 * lock on parent to free or even invalidate a node

	 */

	BUG_ON(op->lock <= b->level);

	BUG_ON(b == b->c->root);

	pr_debug("bucket %s", pbtree(b));



	if (btree_node_dirty(b))

		btree_complete_write(b, btree_current_write(b));
@@ -1012,12 +1011,16 @@ retry: 
	bch_bset_init_next(b);



	mutex_unlock(&c->bucket_lock);



	trace_bcache_btree_node_alloc(b);

	return b;

err_free:

	bch_bucket_free(c, &k.key);

	__bkey_put(c, &k.key);

err:

	mutex_unlock(&c->bucket_lock);



	trace_bcache_btree_node_alloc_fail(b);

	return b;

}
@@ -1254,7 +1257,7 @@ static void btree_gc_coalesce(struct btree *b, struct btree_op *op, 
	btree_node_free(r->b, op);

	up_write(&r->b->lock);



	pr_debug("coalesced %u nodes", nodes);

	trace_bcache_btree_gc_coalesce(nodes);



	gc->nodes--;

	nodes--;
@@ -1479,8 +1482,7 @@ static void bch_btree_gc(struct closure *cl) 
	struct btree_op op;

	uint64_t start_time = local_clock();



	trace_bcache_gc_start(c->sb.set_uuid);

	blktrace_msg_all(c, "Starting gc");

	trace_bcache_gc_start(c);



	memset(&stats, 0, sizeof(struct gc_stat));

	closure_init_stack(&writes);
@@ -1496,9 +1498,7 @@ static void bch_btree_gc(struct closure *cl) 
	closure_sync(&writes);



	if (ret) {

		blktrace_msg_all(c, "Stopped gc");

		pr_warn("gc failed!");



		continue_at(cl, bch_btree_gc, bch_gc_wq);

	}
@@ -1519,8 +1519,7 @@ static void bch_btree_gc(struct closure *cl) 
	stats.in_use	= (c->nbuckets - available) * 100 / c->nbuckets;

	memcpy(&c->gc_stats, &stats, sizeof(struct gc_stat));



	blktrace_msg_all(c, "Finished gc");

	trace_bcache_gc_end(c->sb.set_uuid);

	trace_bcache_gc_end(c);



	continue_at(cl, bch_moving_gc, bch_gc_wq);

}
@@ -1901,12 +1900,11 @@ static int btree_split(struct btree *b, struct btree_op *op) 


	split = set_blocks(n1->sets[0].data, n1->c) > (btree_blocks(b) * 4) / 5;



	pr_debug("%ssplitting at %s keys %i", split ? "" : "not ",

		 pbtree(b), n1->sets[0].data->keys);



	if (split) {

		unsigned keys = 0;



		trace_bcache_btree_node_split(b, n1->sets[0].data->keys);



		n2 = bch_btree_node_alloc(b->c, b->level, &op->cl);

		if (IS_ERR(n2))

			goto err_free1;
@@ -1941,8 +1939,11 @@ static int btree_split(struct btree *b, struct btree_op *op) 
		bch_keylist_add(&op->keys, &n2->key);

		bch_btree_node_write(n2, &op->cl);

		rw_unlock(true, n2);

	} else

	} else {

		trace_bcache_btree_node_compact(b, n1->sets[0].data->keys);



		bch_btree_insert_keys(n1, op);

	}



	bch_keylist_add(&op->keys, &n1->key);

	bch_btree_node_write(n1, &op->cl);
@@ -2117,6 +2118,8 @@ void bch_btree_set_root(struct btree *b) 
{

	unsigned i;



	trace_bcache_btree_set_root(b);



	BUG_ON(!b->written);



	for (i = 0; i < KEY_PTRS(&b->key); i++)
@@ -2130,7 +2133,6 @@ void bch_btree_set_root(struct btree *b) 
	__bkey_put(b->c, &b->key);



	bch_journal_meta(b->c, NULL);

	pr_debug("%s for %pf", pbtree(b), __builtin_return_address(0));

}



/* Cache lookup */
@@ -2216,7 +2218,6 @@ static int submit_partial_cache_hit(struct btree *b, struct btree_op *op, 
		n->bi_end_io	= bch_cache_read_endio;

		n->bi_private	= &s->cl;



		trace_bcache_cache_hit(n);

		__bch_submit_bbio(n, b->c);

	}

drivers/md/bcache/io.c

+2 −0
Original line number Diff line number Diff line
@@ -9,6 +9,8 @@ 
#include "bset.h"

#include "debug.h"



#include <linux/blkdev.h>



static void bch_bi_idx_hack_endio(struct bio *bio, int error)

{

	struct bio *p = bio->bi_private;

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