drivers/gator/gator_events_block.c

   1 /**
   2  * Copyright (C) ARM Limited 2010-2014. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include "gator.h"
  11 #include <trace/events/block.h>
  12
  13 #define BLOCK_RQ_WR             0
  14 #define BLOCK_RQ_RD             1
  15
  16 #define BLOCK_TOTAL             (BLOCK_RQ_RD+1)
  17
  18 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 36)
  19 #define EVENTWRITE REQ_RW
  20 #else
  21 #define EVENTWRITE REQ_WRITE
  22 #endif
  23
  24 static ulong block_rq_wr_enabled;
  25 static ulong block_rq_rd_enabled;
  26 static ulong block_rq_wr_key;
  27 static ulong block_rq_rd_key;
  28 static atomic_t blockCnt[BLOCK_TOTAL];
  29 static int blockGet[BLOCK_TOTAL * 4];
  30
  31 GATOR_DEFINE_PROBE(block_rq_complete, TP_PROTO(struct request_queue *q, struct request *rq))
  32 {
  33         int write, size;
  34
  35         if (!rq)
  36                 return;
  37
  38         write = rq->cmd_flags & EVENTWRITE;
  39         size = rq->resid_len;
  40
  41         if (!size)
  42                 return;
  43
  44         if (write) {
  45                 if (block_rq_wr_enabled) {
  46                         atomic_add(size, &blockCnt[BLOCK_RQ_WR]);
  47                 }
  48         } else {
  49                 if (block_rq_rd_enabled) {
  50                         atomic_add(size, &blockCnt[BLOCK_RQ_RD]);
  51                 }
  52         }
  53 }
  54
  55 static int gator_events_block_create_files(struct super_block *sb, struct dentry *root)
  56 {
  57         struct dentry *dir;
  58
  59         /* block_complete_wr */
  60         dir = gatorfs_mkdir(sb, root, "Linux_block_rq_wr");
  61         if (!dir) {
  62                 return -1;
  63         }
  64         gatorfs_create_ulong(sb, dir, "enabled", &block_rq_wr_enabled);
  65         gatorfs_create_ro_ulong(sb, dir, "key", &block_rq_wr_key);
  66
  67         /* block_complete_rd */
  68         dir = gatorfs_mkdir(sb, root, "Linux_block_rq_rd");
  69         if (!dir) {
  70                 return -1;
  71         }
  72         gatorfs_create_ulong(sb, dir, "enabled", &block_rq_rd_enabled);
  73         gatorfs_create_ro_ulong(sb, dir, "key", &block_rq_rd_key);
  74
  75         return 0;
  76 }
  77
  78 static int gator_events_block_start(void)
  79 {
  80         // register tracepoints
  81         if (block_rq_wr_enabled || block_rq_rd_enabled)
  82                 if (GATOR_REGISTER_TRACE(block_rq_complete))
  83                         goto fail_block_rq_exit;
  84         pr_debug("gator: registered block event tracepoints\n");
  85
  86         return 0;
  87
  88         // unregister tracepoints on error
  89 fail_block_rq_exit:
  90         pr_err("gator: block event tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n");
  91
  92         return -1;
  93 }
  94
  95 static void gator_events_block_stop(void)
  96 {
  97         if (block_rq_wr_enabled || block_rq_rd_enabled)
  98                 GATOR_UNREGISTER_TRACE(block_rq_complete);
  99         pr_debug("gator: unregistered block event tracepoints\n");
 100
 101         block_rq_wr_enabled = 0;
 102         block_rq_rd_enabled = 0;
 103 }
 104
 105 static int gator_events_block_read(int **buffer)
 106 {
 107         int len, value, data = 0;
 108
 109         if (!on_primary_core()) {
 110                 return 0;
 111         }
 112
 113         len = 0;
 114         if (block_rq_wr_enabled && (value = atomic_read(&blockCnt[BLOCK_RQ_WR])) > 0) {
 115                 atomic_sub(value, &blockCnt[BLOCK_RQ_WR]);
 116                 blockGet[len++] = block_rq_wr_key;
 117                 blockGet[len++] = 0;    // indicates to Streamline that value bytes were written now, not since the last message
 118                 blockGet[len++] = block_rq_wr_key;
 119                 blockGet[len++] = value;
 120                 data += value;
 121         }
 122         if (block_rq_rd_enabled && (value = atomic_read(&blockCnt[BLOCK_RQ_RD])) > 0) {
 123                 atomic_sub(value, &blockCnt[BLOCK_RQ_RD]);
 124                 blockGet[len++] = block_rq_rd_key;
 125                 blockGet[len++] = 0;    // indicates to Streamline that value bytes were read now, not since the last message
 126                 blockGet[len++] = block_rq_rd_key;
 127                 blockGet[len++] = value;
 128                 data += value;
 129         }
 130
 131         if (buffer)
 132                 *buffer = blockGet;
 133
 134         return len;
 135 }
 136
 137 static struct gator_interface gator_events_block_interface = {
 138         .create_files = gator_events_block_create_files,
 139         .start = gator_events_block_start,
 140         .stop = gator_events_block_stop,
 141         .read = gator_events_block_read,
 142 };
 143
 144 int gator_events_block_init(void)
 145 {
 146         block_rq_wr_enabled = 0;
 147         block_rq_rd_enabled = 0;
 148
 149         block_rq_wr_key = gator_events_get_key();
 150         block_rq_rd_key = gator_events_get_key();
 151
 152         return gator_events_install(&gator_events_block_interface);
 153 }