Enhanced partition statistics: core statistics

This patch contain the core infrastructure of enhanced partition
statistics. It adds to struct hd_struct the same stats data as struct
gendisk and define basics function to manipulate them.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 141 insertions, 10 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 1dbea0ac5693..589830aca99d 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -91,6 +91,15 @@ struct partition {
         __le32 nr_sects;                /* nr of sectors in partition */
 } __attribute__((packed));
 
+struct disk_stats {
+        unsigned long sectors[2];       /* READs and WRITEs */
+        unsigned long ios[2];
+        unsigned long merges[2];
+        unsigned long ticks[2];
+        unsigned long io_ticks;
+        unsigned long time_in_queue;
+};
+        
 struct hd_struct {
         sector_t start_sect;
         sector_t nr_sects;
@@ -101,6 +110,13 @@ struct hd_struct {
 #ifdef CONFIG_FAIL_MAKE_REQUEST
         int make_it_fail;
 #endif
+        unsigned long stamp;
+        int in_flight;
+#ifdef  CONFIG_SMP
+        struct disk_stats *dkstats;
+#else
+        struct disk_stats dkstats;
+#endif
 };
 
 #define GENHD_FL_REMOVABLE                      1
@@ -111,15 +127,7 @@ struct hd_struct {
 #define GENHD_FL_SUPPRESS_PARTITION_INFO        32
 #define GENHD_FL_FAIL                           64
 
-struct disk_stats {
-        unsigned long sectors[2];       /* READs and WRITEs */
-        unsigned long ios[2];
-        unsigned long merges[2];
-        unsigned long ticks[2];
-        unsigned long io_ticks;
-        unsigned long time_in_queue;
-};
-        
+
 struct gendisk {
         int major;                      /* major number of driver */
         int first_minor;
@@ -158,6 +166,20 @@ struct gendisk {
  * The __ variants should only be called in critical sections. The full
  * variants disable/enable preemption.
  */
+static inline struct hd_struct *get_part(struct gendisk *gendiskp,
+                                         sector_t sector)
+{
+        struct hd_struct *part;
+        int i;
+        for (i = 0; i < gendiskp->minors - 1; i++) {
+                part = gendiskp->part[i];
+                if (part && part->start_sect <= sector
+                    && sector < part->start_sect + part->nr_sects)
+                        return part;
+        }
+        return NULL;
+}
+
 #ifdef  CONFIG_SMP
 #define __disk_stat_add(gendiskp, field, addnd)         \
         (per_cpu_ptr(gendiskp->dkstats, smp_processor_id())->field += addnd)
@@ -177,15 +199,62 @@ static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)	{
                 memset(per_cpu_ptr(gendiskp->dkstats, i), value,
                                 sizeof (struct disk_stats));
 }               
+
+#define __part_stat_add(part, field, addnd)                             \
+        (per_cpu_ptr(part->dkstats, smp_processor_id())->field += addnd)
+
+#define __all_stat_add(gendiskp, field, addnd, sector)          \
+({                                                              \
+        struct hd_struct *part = get_part(gendiskp, sector);    \
+        if (part)                                               \
+                __part_stat_add(part, field, addnd);            \
+        __disk_stat_add(gendiskp, field, addnd);                \
+})
+
+#define part_stat_read(part, field)                                     \
+({                                                                      \
+        typeof(part->dkstats->field) res = 0;                           \
+        int i;                                                          \
+        for_each_possible_cpu(i)                                        \
+                res += per_cpu_ptr(part->dkstats, i)->field;            \
+        res;                                                            \
+})
+
+static inline void part_stat_set_all(struct hd_struct *part, int value) {
+        int i;
+        for_each_possible_cpu(i)
+                memset(per_cpu_ptr(part->dkstats, i), value,
+                       sizeof(struct disk_stats));
+}
                                 
 #else
 #define __disk_stat_add(gendiskp, field, addnd) \
                                 (gendiskp->dkstats.field += addnd)
 #define disk_stat_read(gendiskp, field) (gendiskp->dkstats.field)
 
-static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)       {
+static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)
+{
         memset(&gendiskp->dkstats, value, sizeof (struct disk_stats));
 }
+
+#define __part_stat_add(part, field, addnd) \
+        (part->dkstats.field += addnd)
+
+#define __all_stat_add(gendiskp, field, addnd, sector)          \
+({                                                              \
+        struct hd_struct *part = get_part(gendiskp, sector);    \
+        if (part)                                               \
+                part->dkstats.field += addnd;                   \
+        __disk_stat_add(gendiskp, field, addnd);                \
+})
+
+#define part_stat_read(part, field)     (part->dkstats.field)
+
+static inline void part_stat_set_all(struct hd_struct *part, int value)
+{
+        memset(&part->dkstats, value, sizeof(struct disk_stats));
+}
+
 #endif
 
 #define disk_stat_add(gendiskp, field, addnd)                   \
@@ -206,6 +275,45 @@ static inline void disk_stat_set_all(struct gendisk *gendiskp, int value)	{
 #define disk_stat_sub(gendiskp, field, subnd) \
                 disk_stat_add(gendiskp, field, -subnd)
 
+#define part_stat_add(gendiskp, field, addnd)           \
+        do {                                            \
+                preempt_disable();                      \
+                __part_stat_add(gendiskp, field, addnd);\
+                preempt_enable();                       \
+        } while (0)
+
+#define __part_stat_dec(gendiskp, field) __part_stat_add(gendiskp, field, -1)
+#define part_stat_dec(gendiskp, field) part_stat_add(gendiskp, field, -1)
+
+#define __part_stat_inc(gendiskp, field) __part_stat_add(gendiskp, field, 1)
+#define part_stat_inc(gendiskp, field) part_stat_add(gendiskp, field, 1)
+
+#define __part_stat_sub(gendiskp, field, subnd) \
+                __part_stat_add(gendiskp, field, -subnd)
+#define part_stat_sub(gendiskp, field, subnd) \
+                part_stat_add(gendiskp, field, -subnd)
+
+#define all_stat_add(gendiskp, field, addnd, sector)            \
+        do {                                                    \
+                preempt_disable();                              \
+                __all_stat_add(gendiskp, field, addnd, sector); \
+                preempt_enable();                               \
+        } while (0)
+
+#define __all_stat_dec(gendiskp, field, sector) \
+                __all_stat_add(gendiskp, field, -1, sector)
+#define all_stat_dec(gendiskp, field, sector) \
+                all_stat_add(gendiskp, field, -1, sector)
+
+#define __all_stat_inc(gendiskp, field, sector) \
+                __all_stat_add(gendiskp, field, 1, sector)
+#define all_stat_inc(gendiskp, field, sector) \
+                all_stat_add(gendiskp, field, 1, sector)
+
+#define __all_stat_sub(gendiskp, field, subnd, sector) \
+                __all_stat_add(gendiskp, field, -subnd, sector)
+#define all_stat_sub(gendiskp, field, subnd, sector) \
+                all_stat_add(gendiskp, field, -subnd, sector)
 
 /* Inlines to alloc and free disk stats in struct gendisk */
 #ifdef  CONFIG_SMP
@@ -221,6 +329,20 @@ static inline void free_disk_stats(struct gendisk *disk)
 {
         free_percpu(disk->dkstats);
 }
+
+static inline int init_part_stats(struct hd_struct *part)
+{
+        part->dkstats = alloc_percpu(struct disk_stats);
+        if (!part->dkstats)
+                return 0;
+        return 1;
+}
+
+static inline void free_part_stats(struct hd_struct *part)
+{
+        free_percpu(part->dkstats);
+}
+
 #else   /* CONFIG_SMP */
 static inline int init_disk_stats(struct gendisk *disk)
 {
@@ -230,6 +352,15 @@ static inline int init_disk_stats(struct gendisk *disk)
 static inline void free_disk_stats(struct gendisk *disk)
 {
 }
+
+static inline int init_part_stats(struct hd_struct *part)
+{
+        return 1;
+}
+
+static inline void free_part_stats(struct hd_struct *part)
+{
+}
 #endif  /* CONFIG_SMP */
 
 /* drivers/block/ll_rw_blk.c */