With config MOUNT_IO_STATS, add an array of counters to struct mnt_pcp
that will be used to collect I/O statistics.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
Please note that the dependency on SMP is just for the RFC.
Thanks,
Amir.
fs/Kconfig | 9 +++++++++
fs/mount.h | 32 ++++++++++++++++++++++++++++++++
fs/namespace.c | 17 +++++++++++++++++
3 files changed, 58 insertions(+)
diff --git a/fs/Kconfig b/fs/Kconfig
index aa4c12282301..7473bdf4bbfb 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -15,6 +15,15 @@ config VALIDATE_FS_PARSER
Enable this to perform validation of the parameter description for a
filesystem when it is registered.
+config FS_MOUNT_STATS
+ bool "Enable per-mount I/O statistics"
+ depends on SMP
+ help
+ Enable this to allow collecting per-mount I/O statistics and display
+ them in /proc/<pid>/mountstats.
+
+ Say N if unsure.
+
if BLOCK
config FS_IOMAP
diff --git a/fs/mount.h b/fs/mount.h
index ce6c376e0bc2..2bf0df64ded5 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -24,9 +24,25 @@ struct mnt_namespace {
unsigned int pending_mounts;
} __randomize_layout;
+/* Similar to task_io_accounting members */
+enum {
+ MNTIOS_CHARS_RD, /* bytes read via syscalls */
+ MNTIOS_CHARS_WR, /* bytes written via syscalls */
+ MNTIOS_SYSCALLS_RD, /* # of read syscalls */
+ MNTIOS_SYSCALLS_WR, /* # of write syscalls */
+ _MNTIOS_COUNTERS_NUM
+};
+
+struct mnt_iostats {
+ s64 counter[_MNTIOS_COUNTERS_NUM];
+};
+
struct mnt_pcp {
int mnt_count;
int mnt_writers;
+#ifdef CONFIG_FS_MOUNT_STATS
+ struct mnt_iostats iostats;
+#endif
};
struct mountpoint {
@@ -158,3 +174,19 @@ static inline bool is_anon_ns(struct mnt_namespace *ns)
}
extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor);
+
+static inline void mnt_iostats_counter_inc(struct mount *mnt, int id)
+{
+#ifdef CONFIG_FS_MOUNT_STATS
+ this_cpu_inc(mnt->mnt_pcp->iostats.counter[id]);
+#endif
+}
+
+static inline void mnt_iostats_counter_add(struct mount *mnt, int id, s64 n)
+{
+#ifdef CONFIG_FS_MOUNT_STATS
+ this_cpu_add(mnt->mnt_pcp->iostats.counter[id], n);
+#endif
+}
+
+extern s64 mnt_iostats_counter_read(struct mount *mnt, int id);
diff --git a/fs/namespace.c b/fs/namespace.c
index d2db7dfe232b..04b35dfcc71f 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -283,6 +283,23 @@ static unsigned int mnt_get_writers(struct mount *mnt)
#endif
}
+s64 mnt_iostats_counter_read(struct mount *mnt, int id)
+{
+ s64 count = 0;
+#ifdef CONFIG_FS_MOUNT_STATS
+ /*
+ * MOUNT_STATS depends on SMP.
+ * Should be trivial to implement for !SMP if anyone cares...
+ */
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ count += per_cpu_ptr(mnt->mnt_pcp, cpu)->iostats.counter[id];
+ }
+#endif
+ return count;
+}
+
static int mnt_is_readonly(struct vfsmount *mnt)
{
if (mnt->mnt_sb->s_readonly_remount)
--
2.25.1
