Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-android

[firefly-linux-kernel-4.4.55.git] / include / linux / blkdev.h

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index fe14382f966451b0dd1448634788845fee6e282c..a9562bb029d00ad3dddd551ec35ef9f361c44872 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -197,6 +197,9 @@ struct request {
 
        /* for bidi */
        struct request *next_rq;
+
+       ktime_t                 lat_hist_io_start;
+       int                     lat_hist_enabled;
 };
 
 static inline unsigned short req_get_ioprio(struct request *req)
@@ -1656,6 +1659,79 @@ extern int bdev_write_page(struct block_device *, sector_t, struct page *,
                                                struct writeback_control *);
 extern long bdev_direct_access(struct block_device *, sector_t,
                void __pmem **addr, unsigned long *pfn, long size);
+
+/*
+ * X-axis for IO latency histogram support.
+ */
+static const u_int64_t latency_x_axis_us[] = {
+       100,
+       200,
+       300,
+       400,
+       500,
+       600,
+       700,
+       800,
+       900,
+       1000,
+       1200,
+       1400,
+       1600,
+       1800,
+       2000,
+       2500,
+       3000,
+       4000,
+       5000,
+       6000,
+       7000,
+       9000,
+       10000
+};
+
+#define BLK_IO_LAT_HIST_DISABLE         0
+#define BLK_IO_LAT_HIST_ENABLE          1
+#define BLK_IO_LAT_HIST_ZERO            2
+
+struct io_latency_state {
+       u_int64_t       latency_y_axis_read[ARRAY_SIZE(latency_x_axis_us) + 1];
+       u_int64_t       latency_reads_elems;
+       u_int64_t       latency_y_axis_write[ARRAY_SIZE(latency_x_axis_us) + 1];
+       u_int64_t       latency_writes_elems;
+};
+
+static inline void
+blk_update_latency_hist(struct io_latency_state *s,
+                       int read,
+                       u_int64_t delta_us)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(latency_x_axis_us); i++) {
+               if (delta_us < (u_int64_t)latency_x_axis_us[i]) {
+                       if (read)
+                               s->latency_y_axis_read[i]++;
+                       else
+                               s->latency_y_axis_write[i]++;
+                       break;
+               }
+       }
+       if (i == ARRAY_SIZE(latency_x_axis_us)) {
+               /* Overflowed the histogram */
+               if (read)
+                       s->latency_y_axis_read[i]++;
+               else
+                       s->latency_y_axis_write[i]++;
+       }
+       if (read)
+               s->latency_reads_elems++;
+       else
+               s->latency_writes_elems++;
+}
+
+void blk_zero_latency_hist(struct io_latency_state *s);
+ssize_t blk_latency_hist_show(struct io_latency_state *s, char *buf);
+
 #else /* CONFIG_BLOCK */
 
 struct block_device;