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authorOmar Sandoval <osandov@fb.com>2018-09-27 22:55:53 (GMT)
committerJens Axboe <axboe@kernel.dk>2018-09-27 23:34:56 (GMT)
commitfa2a1f609e6491383ab63ff6329e0aaa2db2b9f7 (patch)
treea3bf07ac5b8ec7c46705c0efdfddfe3d8a8b70bc /block/kyber-iosched.c
parentf8232f29ca268b0ba9e98638c9ed71e337e7f0a4 (diff)
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kyber: don't make domain token sbitmap larger than necessary
The domain token sbitmaps are currently initialized to the device queue depth or 256, whichever is larger, and immediately resized to the maximum depth for that domain (256, 128, or 64 for read, write, and other, respectively). The sbitmap is never resized larger than that, so it's unnecessary to allocate a bitmap larger than the maximum depth. Let's just allocate it to the maximum depth to begin with. This will use marginally less memory, and more importantly, give us a more appropriate number of bits per sbitmap word. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/kyber-iosched.c')
-rw-r--r--block/kyber-iosched.c15
1 files changed, 2 insertions, 13 deletions
diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c
index 95d062c..08eb529 100644
--- a/block/kyber-iosched.c
+++ b/block/kyber-iosched.c
@@ -40,8 +40,6 @@ enum {
};
enum {
- KYBER_MIN_DEPTH = 256,
-
/*
* In order to prevent starvation of synchronous requests by a flood of
* asynchronous requests, we reserve 25% of requests for synchronous
@@ -305,7 +303,6 @@ static int kyber_bucket_fn(const struct request *rq)
static struct kyber_queue_data *kyber_queue_data_alloc(struct request_queue *q)
{
struct kyber_queue_data *kqd;
- unsigned int max_tokens;
unsigned int shift;
int ret = -ENOMEM;
int i;
@@ -320,25 +317,17 @@ static struct kyber_queue_data *kyber_queue_data_alloc(struct request_queue *q)
if (!kqd->cb)
goto err_kqd;
- /*
- * The maximum number of tokens for any scheduling domain is at least
- * the queue depth of a single hardware queue. If the hardware doesn't
- * have many tags, still provide a reasonable number.
- */
- max_tokens = max_t(unsigned int, q->tag_set->queue_depth,
- KYBER_MIN_DEPTH);
for (i = 0; i < KYBER_NUM_DOMAINS; i++) {
WARN_ON(!kyber_depth[i]);
WARN_ON(!kyber_batch_size[i]);
ret = sbitmap_queue_init_node(&kqd->domain_tokens[i],
- max_tokens, -1, false, GFP_KERNEL,
- q->node);
+ kyber_depth[i], -1, false,
+ GFP_KERNEL, q->node);
if (ret) {
while (--i >= 0)
sbitmap_queue_free(&kqd->domain_tokens[i]);
goto err_cb;
}
- sbitmap_queue_resize(&kqd->domain_tokens[i], kyber_depth[i]);
}
shift = kyber_sched_tags_shift(kqd);