Revert "Android: MMC/UFS IO Latency Histograms."

This reverts commit 9c2c807ed6ccab2ded416909b8c135acab33483c.

Change-Id: I917190cbf601c34ee03b714389351b4985733b80

9 files changed, 3 insertions, 320 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index a06394fcbdf5..03b5f8d77f37 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -3364,83 +3364,3 @@ int __init blk_dev_init(void)
 
 	return 0;
 }
-
-/*
- * Blk IO latency support. We want this to be as cheap as possible, so doing
- * this lockless (and avoiding atomics), a few off by a few errors in this
- * code is not harmful, and we don't want to do anything that is
- * perf-impactful.
- * TODO : If necessary, we can make the histograms per-cpu and aggregate
- * them when printing them out.
- */
-void
-blk_zero_latency_hist(struct io_latency_state *s)
-{
-	memset(s->latency_y_axis_read, 0,
-	       sizeof(s->latency_y_axis_read));
-	memset(s->latency_y_axis_write, 0,
-	       sizeof(s->latency_y_axis_write));
-	s->latency_reads_elems = 0;
-	s->latency_writes_elems = 0;
-}
-
-ssize_t
-blk_latency_hist_show(struct io_latency_state *s, char *buf)
-{
-	int i;
-	int bytes_written = 0;
-	int pct, num_elem;
-	u_int64_t elem;
-
-	num_elem = s->latency_reads_elems;
-	if (num_elem > 0) {
-		bytes_written += scnprintf(buf + bytes_written,
-			   PAGE_SIZE - bytes_written,
-			   "IO svc_time Read Latency Histogram (n = %d):\n",
-			   num_elem);
-		for (i = 0;
-		     i < ARRAY_SIZE(latency_x_axis_us);
-		     i++) {
-			elem = s->latency_y_axis_read[i];
-			pct = (elem * 100) / num_elem;
-			bytes_written += scnprintf(buf + bytes_written,
-						   PAGE_SIZE - bytes_written,
-						   "\t< %5lluus%15llu%15d%%\n",
-						   latency_x_axis_us[i],
-						   elem, pct);
-		}
-		/* Last element in y-axis table is overflow */
-		elem = s->latency_y_axis_read[i];
-		pct = (elem * 100) / num_elem;
-		bytes_written += scnprintf(buf + bytes_written,
-					   PAGE_SIZE - bytes_written,
-					   "\t> %5dms%15llu%15d%%\n", 10,
-					   elem, pct);
-	}
-	num_elem = s->latency_writes_elems;
-	if (num_elem > 0) {
-		bytes_written += scnprintf(buf + bytes_written,
-			   PAGE_SIZE - bytes_written,
-			   "IO svc_time Write Latency Histogram (n = %d):\n",
-			   num_elem);
-		for (i = 0;
-		     i < ARRAY_SIZE(latency_x_axis_us);
-		     i++) {
-			elem = s->latency_y_axis_write[i];
-			pct = (elem * 100) / num_elem;
-			bytes_written += scnprintf(buf + bytes_written,
-						   PAGE_SIZE - bytes_written,
-						   "\t< %5lluus%15llu%15d%%\n",
-						   latency_x_axis_us[i],
-						   elem, pct);
-		}
-		/* Last element in y-axis table is overflow */
-		elem = s->latency_y_axis_write[i];
-		pct = (elem * 100) / num_elem;
-		bytes_written += scnprintf(buf + bytes_written,
-					   PAGE_SIZE - bytes_written,
-					   "\t> %5dms%15llu%15d%%\n", 10,
-					   elem, pct);
-	}
-	return bytes_written;
-}
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index f0cb3ad3421f..ebfb3606f7a3 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -169,17 +169,6 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
 			pr_debug("%s:     %d bytes transferred: %d\n",
 				mmc_hostname(host),
 				mrq->data->bytes_xfered, mrq->data->error);
-			if (mrq->lat_hist_enabled) {
-				ktime_t completion;
-				u_int64_t delta_us;
-
-				completion = ktime_get();
-				delta_us = ktime_us_delta(completion,
-							  mrq->io_start);
-				blk_update_latency_hist(&host->io_lat_s,
-					(mrq->data->flags & MMC_DATA_READ),
-					delta_us);
-			}
 			trace_mmc_blk_rw_end(cmd->opcode, cmd->arg, mrq->data);
 		}
 
@@ -588,11 +577,6 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
 	}
 
 	if (!err && areq) {
-		if (host->latency_hist_enabled) {
-			areq->mrq->io_start = ktime_get();
-			areq->mrq->lat_hist_enabled = 1;
-		} else
-			areq->mrq->lat_hist_enabled = 0;
 		trace_mmc_blk_rw_start(areq->mrq->cmd->opcode,
 				       areq->mrq->cmd->arg,
 				       areq->mrq->data);
@@ -1887,7 +1871,7 @@ void mmc_init_erase(struct mmc_card *card)
 }
 
 static unsigned int mmc_mmc_erase_timeout(struct mmc_card *card,
-					  unsigned int arg, unsigned int qty)
+				          unsigned int arg, unsigned int qty)
 {
 	unsigned int erase_timeout;
 
@@ -2793,54 +2777,6 @@ static void __exit mmc_exit(void)
 	destroy_workqueue(workqueue);
 }
 
-static ssize_t
-latency_hist_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
-	struct mmc_host *host = cls_dev_to_mmc_host(dev);
-
-	return blk_latency_hist_show(&host->io_lat_s, buf);
-}
-
-/*
- * Values permitted 0, 1, 2.
- * 0 -> Disable IO latency histograms (default)
- * 1 -> Enable IO latency histograms
- * 2 -> Zero out IO latency histograms
- */
-static ssize_t
-latency_hist_store(struct device *dev, struct device_attribute *attr,
-		   const char *buf, size_t count)
-{
-	struct mmc_host *host = cls_dev_to_mmc_host(dev);
-	long value;
-
-	if (kstrtol(buf, 0, &value))
-		return -EINVAL;
-	if (value == BLK_IO_LAT_HIST_ZERO)
-		blk_zero_latency_hist(&host->io_lat_s);
-	else if (value == BLK_IO_LAT_HIST_ENABLE ||
-		 value == BLK_IO_LAT_HIST_DISABLE)
-		host->latency_hist_enabled = value;
-	return count;
-}
-
-static DEVICE_ATTR(latency_hist, S_IRUGO | S_IWUSR,
-		   latency_hist_show, latency_hist_store);
-
-void
-mmc_latency_hist_sysfs_init(struct mmc_host *host)
-{
-	if (device_create_file(&host->class_dev, &dev_attr_latency_hist))
-		dev_err(&host->class_dev,
-			"Failed to create latency_hist sysfs entry\n");
-}
-
-void
-mmc_latency_hist_sysfs_exit(struct mmc_host *host)
-{
-	device_remove_file(&host->class_dev, &dev_attr_latency_hist);
-}
-
 subsys_initcall(mmc_init);
 module_exit(mmc_exit);
 
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index b59b585dbd6c..a3d94d1675f5 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -32,6 +32,8 @@
 #include "slot-gpio.h"
 #include "pwrseq.h"
 
+#define cls_dev_to_mmc_host(d)	container_of(d, struct mmc_host, class_dev)
+
 static DEFINE_IDR(mmc_host_idr);
 static DEFINE_SPINLOCK(mmc_host_lock);
 
@@ -545,8 +547,6 @@ int mmc_add_host(struct mmc_host *host)
 #endif
 	mmc_host_clk_sysfs_init(host);
 
-	mmc_latency_hist_sysfs_init(host);
-
 	mmc_start_host(host);
 	if (!(host->pm_flags & MMC_PM_IGNORE_PM_NOTIFY))
 		register_pm_notifier(&host->pm_notify);
@@ -575,8 +575,6 @@ void mmc_remove_host(struct mmc_host *host)
 	mmc_remove_host_debugfs(host);
 #endif
 
-	mmc_latency_hist_sysfs_exit(host);
-
 	device_del(&host->class_dev);
 
 	led_trigger_unregister_simple(host->led);
diff --git a/drivers/mmc/core/host.h b/drivers/mmc/core/host.h
index 4dcf49937ecd..f2ab9e578126 100644
--- a/drivers/mmc/core/host.h
+++ b/drivers/mmc/core/host.h
@@ -12,13 +12,8 @@
 #define _MMC_CORE_HOST_H
 #include <linux/mmc/host.h>
 
-#define cls_dev_to_mmc_host(d)	container_of(d, struct mmc_host, class_dev)
-
 int mmc_register_host_class(void);
 void mmc_unregister_host_class(void);
 
-void mmc_latency_hist_sysfs_init(struct mmc_host *host);
-void mmc_latency_hist_sysfs_exit(struct mmc_host *host);
-
 #endif
 
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 2188c0af45c1..648a44675880 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -39,7 +39,6 @@
 
 #include <linux/async.h>
 #include <linux/devfreq.h>
-#include <linux/blkdev.h>
 
 #include "ufshcd.h"
 #include "unipro.h"
@@ -1317,17 +1316,6 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 		clear_bit_unlock(tag, &hba->lrb_in_use);
 		goto out;
 	}
-
-	/* IO svc time latency histogram */
-	if (hba != NULL && cmd->request != NULL) {
-		if (hba->latency_hist_enabled &&
-		    (cmd->request->cmd_type == REQ_TYPE_FS)) {
-			cmd->request->lat_hist_io_start = ktime_get();
-			cmd->request->lat_hist_enabled = 1;
-		} else
-			cmd->request->lat_hist_enabled = 0;
-	}
-
 	WARN_ON(hba->clk_gating.state != CLKS_ON);
 
 	lrbp = &hba->lrb[tag];
@@ -3077,7 +3065,6 @@ static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
 	u32 tr_doorbell;
 	int result;
 	int index;
-	struct request *req;
 
 	/* Resetting interrupt aggregation counters first and reading the
 	 * DOOR_BELL afterward allows us to handle all the completed requests.
@@ -3101,22 +3088,6 @@ static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
 			/* Mark completed command as NULL in LRB */
 			lrbp->cmd = NULL;
 			clear_bit_unlock(index, &hba->lrb_in_use);
-			req = cmd->request;
-			if (req) {
-				/* Update IO svc time latency histogram */
-				if (req->lat_hist_enabled) {
-					ktime_t completion;
-					u_int64_t delta_us;
-
-					completion = ktime_get();
-					delta_us = ktime_us_delta(completion,
-						  req->lat_hist_io_start);
-					/* rq_data_dir() => true if WRITE */
-					blk_update_latency_hist(&hba->io_lat_s,
-						(rq_data_dir(req) == READ),
-						delta_us);
-				}
-			}
 			/* Do not touch lrbp after scsi done */
 			cmd->scsi_done(cmd);
 			__ufshcd_release(hba);
@@ -5278,54 +5249,6 @@ out:
 }
 EXPORT_SYMBOL(ufshcd_shutdown);
 
-/*
- * Values permitted 0, 1, 2.
- * 0 -> Disable IO latency histograms (default)
- * 1 -> Enable IO latency histograms
- * 2 -> Zero out IO latency histograms
- */
-static ssize_t
-latency_hist_store(struct device *dev, struct device_attribute *attr,
-		   const char *buf, size_t count)
-{
-	struct ufs_hba *hba = dev_get_drvdata(dev);
-	long value;
-
-	if (kstrtol(buf, 0, &value))
-		return -EINVAL;
-	if (value == BLK_IO_LAT_HIST_ZERO)
-		blk_zero_latency_hist(&hba->io_lat_s);
-	else if (value == BLK_IO_LAT_HIST_ENABLE ||
-		 value == BLK_IO_LAT_HIST_DISABLE)
-		hba->latency_hist_enabled = value;
-	return count;
-}
-
-ssize_t
-latency_hist_show(struct device *dev, struct device_attribute *attr,
-		  char *buf)
-{
-	struct ufs_hba *hba = dev_get_drvdata(dev);
-
-	return blk_latency_hist_show(&hba->io_lat_s, buf);
-}
-
-static DEVICE_ATTR(latency_hist, S_IRUGO | S_IWUSR,
-		   latency_hist_show, latency_hist_store);
-
-static void
-ufshcd_init_latency_hist(struct ufs_hba *hba)
-{
-	if (device_create_file(hba->dev, &dev_attr_latency_hist))
-		dev_err(hba->dev, "Failed to create latency_hist sysfs entry\n");
-}
-
-static void
-ufshcd_exit_latency_hist(struct ufs_hba *hba)
-{
-	device_create_file(hba->dev, &dev_attr_latency_hist);
-}
-
 /**
  * ufshcd_remove - de-allocate SCSI host and host memory space
  *		data structure memory
@@ -5341,7 +5264,6 @@ void ufshcd_remove(struct ufs_hba *hba)
 	scsi_host_put(hba->host);
 
 	ufshcd_exit_clk_gating(hba);
-	ufshcd_exit_latency_hist(hba);
 	if (ufshcd_is_clkscaling_enabled(hba))
 		devfreq_remove_device(hba->devfreq);
 	ufshcd_hba_exit(hba);
@@ -5631,8 +5553,6 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	/* Hold auto suspend until async scan completes */
 	pm_runtime_get_sync(dev);
 
-	ufshcd_init_latency_hist(hba);
-
 	/*
 	 * The device-initialize-sequence hasn't been invoked yet.
 	 * Set the device to power-off state
@@ -5647,7 +5567,6 @@ out_remove_scsi_host:
 	scsi_remove_host(hba->host);
 exit_gating:
 	ufshcd_exit_clk_gating(hba);
-	ufshcd_exit_latency_hist(hba);
 out_disable:
 	hba->is_irq_enabled = false;
 	scsi_host_put(host);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 85f64502c375..b47ff07698e8 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -482,9 +482,6 @@ struct ufs_hba {
 	struct devfreq *devfreq;
 	struct ufs_clk_scaling clk_scaling;
 	bool is_sys_suspended;
-
-	int			latency_hist_enabled;
-	struct io_latency_state io_lat_s;
 };
 
 /* Returns true if clocks can be gated. Otherwise false */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index efdf6a6d0b36..5d93a6645e88 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -209,9 +209,6 @@ 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)
@@ -1626,79 +1623,6 @@ 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 **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;
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 1510a383653d..de722d4e9d61 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -135,8 +135,6 @@ struct mmc_request {
 	struct completion	completion;
 	void			(*done)(struct mmc_request *);/* completion function */
 	struct mmc_host		*host;
-	ktime_t			io_start;
-	int			lat_hist_enabled;
 };
 
 struct mmc_card;
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 31f22edaa581..a233a53ed4e5 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -15,7 +15,6 @@
 #include <linux/sched.h>
 #include <linux/device.h>
 #include <linux/fault-inject.h>
-#include <linux/blkdev.h>
 
 #include <linux/mmc/core.h>
 #include <linux/mmc/card.h>
@@ -380,9 +379,6 @@ struct mmc_host {
 	} embedded_sdio_data;
 #endif
 
-	int			latency_hist_enabled;
-	struct io_latency_state io_lat_s;
-
 	unsigned long		private[0] ____cacheline_aligned;
 };