cfq-iosched: Expose microsecond interfaces

Expose interfaces to tune time slices of CFQ IO scheduler in
microseconds.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 9c2e82c..2db7b14 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -4690,6 +4690,21 @@ SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0);
 SHOW_FUNCTION(cfq_target_latency_show, cfqd->cfq_target_latency, 1);
 #undef SHOW_FUNCTION
 
+#define USEC_SHOW_FUNCTION(__FUNC, __VAR)                              \
+static ssize_t __FUNC(struct elevator_queue *e, char *page)            \
+{                                                                      \
+       struct cfq_data *cfqd = e->elevator_data;                       \
+       u64 __data = __VAR;                                             \
+       __data = div_u64(__data, NSEC_PER_USEC);                        \
+       return cfq_var_show(__data, (page));                            \
+}
+USEC_SHOW_FUNCTION(cfq_slice_idle_us_show, cfqd->cfq_slice_idle);
+USEC_SHOW_FUNCTION(cfq_group_idle_us_show, cfqd->cfq_group_idle);
+USEC_SHOW_FUNCTION(cfq_slice_sync_us_show, cfqd->cfq_slice[1]);
+USEC_SHOW_FUNCTION(cfq_slice_async_us_show, cfqd->cfq_slice[0]);
+USEC_SHOW_FUNCTION(cfq_target_latency_us_show, cfqd->cfq_target_latency);
+#undef USEC_SHOW_FUNCTION
+
 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)                        \
 static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)        \
 {                                                                      \
@@ -4724,6 +4739,26 @@ STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0);
 STORE_FUNCTION(cfq_target_latency_store, &cfqd->cfq_target_latency, 1, UINT_MAX, 1);
 #undef STORE_FUNCTION
 
+#define USEC_STORE_FUNCTION(__FUNC, __PTR, MIN, MAX)                   \
+static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)        \
+{                                                                      \
+       struct cfq_data *cfqd = e->elevator_data;                       \
+       unsigned int __data;                                            \
+       int ret = cfq_var_store(&__data, (page), count);                \
+       if (__data < (MIN))                                             \
+               __data = (MIN);                                         \
+       else if (__data > (MAX))                                        \
+               __data = (MAX);                                         \
+       *(__PTR) = (u64)__data * NSEC_PER_USEC;                         \
+       return ret;                                                     \
+}
+USEC_STORE_FUNCTION(cfq_slice_idle_us_store, &cfqd->cfq_slice_idle, 0, UINT_MAX);
+USEC_STORE_FUNCTION(cfq_group_idle_us_store, &cfqd->cfq_group_idle, 0, UINT_MAX);
+USEC_STORE_FUNCTION(cfq_slice_sync_us_store, &cfqd->cfq_slice[1], 1, UINT_MAX);
+USEC_STORE_FUNCTION(cfq_slice_async_us_store, &cfqd->cfq_slice[0], 1, UINT_MAX);
+USEC_STORE_FUNCTION(cfq_target_latency_us_store, &cfqd->cfq_target_latency, 1, UINT_MAX);
+#undef USEC_STORE_FUNCTION
+
 #define CFQ_ATTR(name) \
        __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store)
 
@@ -4734,12 +4769,17 @@ static struct elv_fs_entry cfq_attrs[] = {
        CFQ_ATTR(back_seek_max),
        CFQ_ATTR(back_seek_penalty),
        CFQ_ATTR(slice_sync),
+       CFQ_ATTR(slice_sync_us),
        CFQ_ATTR(slice_async),
+       CFQ_ATTR(slice_async_us),
        CFQ_ATTR(slice_async_rq),
        CFQ_ATTR(slice_idle),
+       CFQ_ATTR(slice_idle_us),
        CFQ_ATTR(group_idle),
+       CFQ_ATTR(group_idle_us),
        CFQ_ATTR(low_latency),
        CFQ_ATTR(target_latency),
+       CFQ_ATTR(target_latency_us),
        __ATTR_NULL
 };