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Message-Id: <1396277175-21382-4-git-send-email-hch@lst.de>
Date: Mon, 31 Mar 2014 16:46:14 +0200
From: Christoph Hellwig <hch@....de>
To: Jens Axboe <axboe@...com>
Cc: Matias Bjorling <m@...rling.me>, linux-kernel@...r.kernel.org,
linux-scsi@...r.kernel.org
Subject: [PATCH 3/4] blk-mq: move request structures into struct blk_mq_tags
This is in preparation for allowing to share the tags, and thus request
allocation between multiple queues.
Also remove blk_mq_tag_to_rq, as it was unused and thus untestable. If we
need it back it can easil be re-added as a non-inline function.
Note that we also now straight out fail queue initialization if we can't
allocate tags - keeping track of a reduced queue_depth over a more complex
call chain isn't easil possible and this shouldn't happen on an of todays
systems.
Signed-off-by: Christoph Hellwig <hch@....de>
---
block/blk-mq-tag.c | 13 --------
block/blk-mq.c | 84 +++++++++++++++++++++++++-----------------------
block/blk-mq.h | 18 +++++++++++
include/linux/blk-mq.h | 8 -----
4 files changed, 61 insertions(+), 62 deletions(-)
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 83ae96c..108f82b 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -7,19 +7,6 @@
#include "blk-mq.h"
#include "blk-mq-tag.h"
-/*
- * Per tagged queue (tag address space) map
- */
-struct blk_mq_tags {
- unsigned int nr_tags;
- unsigned int nr_reserved_tags;
- unsigned int nr_batch_move;
- unsigned int nr_max_cache;
-
- struct percpu_ida free_tags;
- struct percpu_ida reserved_tags;
-};
-
void blk_mq_wait_for_tags(struct blk_mq_tags *tags)
{
int tag = blk_mq_get_tag(tags, __GFP_WAIT, false);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ec0c276..f1b5d52 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -81,7 +81,7 @@ static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx,
tag = blk_mq_get_tag(hctx->tags, gfp, reserved);
if (tag != BLK_MQ_TAG_FAIL) {
- rq = hctx->rqs[tag];
+ rq = hctx->tags->rqs[tag];
blk_rq_init(hctx->queue, rq);
rq->tag = tag;
@@ -406,7 +406,9 @@ static void blk_mq_timeout_check(void *__data, unsigned long *free_tags)
if (tag >= hctx->queue_depth)
break;
- rq = hctx->rqs[tag++];
+ rq = hctx->tags->rqs[tag++];
+ if (rq->q != hctx->queue)
+ continue;
if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
continue;
@@ -993,7 +995,7 @@ static int blk_mq_init_hw_commands(struct blk_mq_hw_ctx *hctx,
int ret = 0;
for (i = 0; i < hctx->queue_depth; i++) {
- struct request *rq = hctx->rqs[i];
+ struct request *rq = hctx->tags->rqs[i];
ret = init(data, hctx, rq, i);
if (ret)
@@ -1030,7 +1032,7 @@ static void blk_mq_free_hw_commands(struct blk_mq_hw_ctx *hctx,
unsigned int i;
for (i = 0; i < hctx->queue_depth; i++) {
- struct request *rq = hctx->rqs[i];
+ struct request *rq = hctx->tags->rqs[i];
free(data, hctx, rq, i);
}
@@ -1049,20 +1051,19 @@ void blk_mq_free_commands(struct request_queue *q,
}
EXPORT_SYMBOL(blk_mq_free_commands);
-static void blk_mq_free_rq_map(struct blk_mq_hw_ctx *hctx)
+static void blk_mq_free_rq_map(struct blk_mq_tags *tags)
{
struct page *page;
- while (!list_empty(&hctx->page_list)) {
- page = list_first_entry(&hctx->page_list, struct page, lru);
+ while (!list_empty(&tags->page_list)) {
+ page = list_first_entry(&tags->page_list, struct page, lru);
list_del_init(&page->lru);
__free_pages(page, page->private);
}
- kfree(hctx->rqs);
+ kfree(tags->rqs);
- if (hctx->tags)
- blk_mq_free_tags(hctx->tags);
+ blk_mq_free_tags(tags);
}
static size_t order_to_size(unsigned int order)
@@ -1075,28 +1076,35 @@ static size_t order_to_size(unsigned int order)
return ret;
}
-static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
- unsigned int reserved_tags, int node)
+static struct blk_mq_tags *blk_mq_init_rq_map(unsigned int total_tags,
+ unsigned int reserved_tags, unsigned int cmd_size, int node)
{
+ struct blk_mq_tags *tags;
unsigned int i, j, entries_per_page, max_order = 4;
size_t rq_size, left;
- INIT_LIST_HEAD(&hctx->page_list);
+ tags = blk_mq_init_tags(total_tags, reserved_tags, node);
+ if (!tags)
+ return NULL;
+
+ INIT_LIST_HEAD(&tags->page_list);
- hctx->rqs = kmalloc_node(hctx->queue_depth * sizeof(struct request *),
+ tags->rqs = kmalloc_node(total_tags * sizeof(struct request *),
GFP_KERNEL, node);
- if (!hctx->rqs)
- return -ENOMEM;
+ if (!tags->rqs) {
+ blk_mq_free_tags(tags);
+ return NULL;
+ }
/*
* rq_size is the size of the request plus driver payload, rounded
* to the cacheline size
*/
- rq_size = round_up(sizeof(struct request) + hctx->cmd_size,
+ rq_size = round_up(sizeof(struct request) + cmd_size,
cache_line_size());
- left = rq_size * hctx->queue_depth;
+ left = rq_size * total_tags;
- for (i = 0; i < hctx->queue_depth;) {
+ for (i = 0; i < total_tags; ) {
int this_order = max_order;
struct page *page;
int to_do;
@@ -1116,38 +1124,28 @@ static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
} while (1);
if (!page)
- break;
+ goto fail;
page->private = this_order;
- list_add_tail(&page->lru, &hctx->page_list);
+ list_add_tail(&page->lru, &tags->page_list);
p = page_address(page);
entries_per_page = order_to_size(this_order) / rq_size;
- to_do = min(entries_per_page, hctx->queue_depth - i);
+ to_do = min(entries_per_page, total_tags - i);
left -= to_do * rq_size;
for (j = 0; j < to_do; j++) {
- hctx->rqs[i] = p;
+ tags->rqs[i] = p;
p += rq_size;
i++;
}
}
- if (i < (reserved_tags + BLK_MQ_TAG_MIN))
- goto err_rq_map;
- else if (i != hctx->queue_depth) {
- hctx->queue_depth = i;
- pr_warn("%s: queue depth set to %u because of low memory\n",
- __func__, i);
- }
-
- hctx->tags = blk_mq_init_tags(hctx->queue_depth, reserved_tags, node);
- if (!hctx->tags) {
-err_rq_map:
- blk_mq_free_rq_map(hctx);
- return -ENOMEM;
- }
+ return tags;
- return 0;
+fail:
+ pr_warn("%s: failed to allocate requests\n", __func__);
+ blk_mq_free_rq_map(tags);
+ return NULL;
}
static int blk_mq_init_hw_queues(struct request_queue *q,
@@ -1180,7 +1178,9 @@ static int blk_mq_init_hw_queues(struct request_queue *q,
blk_mq_hctx_notify, hctx);
blk_mq_register_cpu_notifier(&hctx->cpu_notifier);
- if (blk_mq_init_rq_map(hctx, reg->reserved_tags, node))
+ hctx->tags = blk_mq_init_rq_map(hctx->queue_depth,
+ reg->reserved_tags, reg->cmd_size, node);
+ if (!hctx->tags)
break;
/*
@@ -1220,7 +1220,8 @@ static int blk_mq_init_hw_queues(struct request_queue *q,
reg->ops->exit_hctx(hctx, j);
blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
- blk_mq_free_rq_map(hctx);
+ if (hctx->tags)
+ blk_mq_free_rq_map(hctx->tags);
kfree(hctx->ctxs);
}
@@ -1397,7 +1398,8 @@ void blk_mq_free_queue(struct request_queue *q)
queue_for_each_hw_ctx(q, hctx, i) {
kfree(hctx->ctx_map);
kfree(hctx->ctxs);
- blk_mq_free_rq_map(hctx);
+ if (hctx->tags)
+ blk_mq_free_rq_map(hctx->tags);
blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
if (q->mq_ops->exit_hctx)
q->mq_ops->exit_hctx(hctx, i);
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 238379a..eca3a47 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -1,6 +1,24 @@
#ifndef INT_BLK_MQ_H
#define INT_BLK_MQ_H
+#include <linux/percpu_ida.h>
+
+/*
+ * Tag address space map.
+ */
+struct blk_mq_tags {
+ unsigned int nr_tags;
+ unsigned int nr_reserved_tags;
+ unsigned int nr_batch_move;
+ unsigned int nr_max_cache;
+
+ struct percpu_ida free_tags;
+ struct percpu_ida reserved_tags;
+
+ struct request **rqs;
+ struct list_head page_list;
+};
+
struct blk_mq_ctx {
struct {
spinlock_t lock;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 0120451..69aa3ad 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -32,8 +32,6 @@ struct blk_mq_hw_ctx {
unsigned int nr_ctx_map;
unsigned long *ctx_map;
- struct request **rqs;
- struct list_head page_list;
struct blk_mq_tags *tags;
unsigned long queued;
@@ -162,12 +160,6 @@ static inline void *blk_mq_rq_to_pdu(struct request *rq)
return (void *) rq + sizeof(*rq);
}
-static inline struct request *blk_mq_tag_to_rq(struct blk_mq_hw_ctx *hctx,
- unsigned int tag)
-{
- return hctx->rqs[tag];
-}
-
#define queue_for_each_hw_ctx(q, hctx, i) \
for ((i) = 0; (i) < (q)->nr_hw_queues && \
({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++)
--
1.7.10.4
--
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