block: get rid of struct blk_issue_stat
struct blk_issue_stat squashes three things into one u64:
- The time the driver started working on a request
- The original size of the request (for the io.low controller)
- Flags for writeback throttling
It turns out that on x86_64, we have a 4 byte hole in struct request
which we can fill with the non-timestamp fields from blk_issue_stat,
simplifying things quite a bit.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 5c4eee0..f2c2fc0 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -206,8 +206,18 @@ struct request {
struct gendisk *rq_disk;
struct hd_struct *part;
unsigned long start_time;
- struct blk_issue_stat issue_stat;
- /* Number of scatter-gather DMA addr+len pairs after
+ /* Time that I/O was submitted to the device. */
+ u64 io_start_time_ns;
+
+#ifdef CONFIG_BLK_WBT
+ unsigned short wbt_flags;
+#endif
+#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
+ unsigned short throtl_size;
+#endif
+
+ /*
+ * Number of scatter-gather DMA addr+len pairs after
* physical address coalescing is performed.
*/
unsigned short nr_phys_segments;
@@ -267,8 +277,8 @@ struct request {
#ifdef CONFIG_BLK_CGROUP
struct request_list *rl; /* rl this rq is alloced from */
- unsigned long long start_time_ns;
- unsigned long long io_start_time_ns; /* when passed to hardware */
+ unsigned long long cgroup_start_time_ns;
+ unsigned long long cgroup_io_start_time_ns; /* when passed to hardware */
#endif
};
@@ -1797,25 +1807,25 @@ int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned lo
static inline void set_start_time_ns(struct request *req)
{
preempt_disable();
- req->start_time_ns = sched_clock();
+ req->cgroup_start_time_ns = sched_clock();
preempt_enable();
}
static inline void set_io_start_time_ns(struct request *req)
{
preempt_disable();
- req->io_start_time_ns = sched_clock();
+ req->cgroup_io_start_time_ns = sched_clock();
preempt_enable();
}
static inline uint64_t rq_start_time_ns(struct request *req)
{
- return req->start_time_ns;
+ return req->cgroup_start_time_ns;
}
static inline uint64_t rq_io_start_time_ns(struct request *req)
{
- return req->io_start_time_ns;
+ return req->cgroup_io_start_time_ns;
}
#else
static inline void set_start_time_ns(struct request *req) {}