Re: [PATCH v6 3/9] fs: add percpu counters for significant multigrain timestamp events
On Mon 15-07-24 15:53:42, Jeff Layton wrote:
> On Mon, 2024-07-15 at 11:32 -0700, Darrick J. Wong wrote:
> > On Mon, Jul 15, 2024 at 08:48:54AM -0400, Jeff Layton wrote:
> > > Four percpu counters for counting various stats around mgtimes, and
> > > a
> > > new debugfs file for displaying them:
> > >
> > > - number of attempted ctime updates
> > > - number of successful i_ctime_nsec swaps
> > > - number of fine-grained timestamp fetches
> > > - number of floor value swaps
> > >
> > > Reviewed-by: Josef Bacik
> > > Signed-off-by: Jeff Layton
> > > ---
> > > fs/inode.c | 70
> > > +-
> > > 1 file changed, 69 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/fs/inode.c b/fs/inode.c
> > > index 869994285e87..fff844345c35 100644
> > > --- a/fs/inode.c
> > > +++ b/fs/inode.c
> > > @@ -21,6 +21,8 @@
> > > #include
> > > #include
> > > #include
> > > +#include
> > > +#include
> > > #include
> > > #define CREATE_TRACE_POINTS
> > > #include
> > > @@ -80,6 +82,10 @@ EXPORT_SYMBOL(empty_aops);
> > >
> > > static DEFINE_PER_CPU(unsigned long, nr_inodes);
> > > static DEFINE_PER_CPU(unsigned long, nr_unused);
> > > +static DEFINE_PER_CPU(unsigned long, mg_ctime_updates);
> > > +static DEFINE_PER_CPU(unsigned long, mg_fine_stamps);
> > > +static DEFINE_PER_CPU(unsigned long, mg_floor_swaps);
> > > +static DEFINE_PER_CPU(unsigned long, mg_ctime_swaps);
> >
> > Should this all get switched off if CONFIG_DEBUG_FS=n?
> >
> > --D
> >
>
> Sure, why not. That's simple enough to do.
>
> I pushed an updated mgtime branch to my git tree. Here's the updated
> patch that's the only difference:
>
>
> https://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux.git/commit/?h=mgtime&id=ee7fe6e9c0598754861c8620230f15f3de538ca5
>
> Seems to build OK both with and without CONFIG_DEBUG_FS.
Looks good to me. Feel free to add:
Reviewed-by: Jan Kara
Honza
>
> > >
> > > static struct kmem_cache *inode_cachep __ro_after_init;
> > >
> > > @@ -101,6 +107,42 @@ static inline long get_nr_inodes_unused(void)
> > > return sum < 0 ? 0 : sum;
> > > }
> > >
> > > +static long get_mg_ctime_updates(void)
> > > +{
> > > + int i;
> > > + long sum = 0;
> > > + for_each_possible_cpu(i)
> > > + sum += per_cpu(mg_ctime_updates, i);
> > > + return sum < 0 ? 0 : sum;
> > > +}
> > > +
> > > +static long get_mg_fine_stamps(void)
> > > +{
> > > + int i;
> > > + long sum = 0;
> > > + for_each_possible_cpu(i)
> > > + sum += per_cpu(mg_fine_stamps, i);
> > > + return sum < 0 ? 0 : sum;
> > > +}
> > > +
> > > +static long get_mg_floor_swaps(void)
> > > +{
> > > + int i;
> > > + long sum = 0;
> > > + for_each_possible_cpu(i)
> > > + sum += per_cpu(mg_floor_swaps, i);
> > > + return sum < 0 ? 0 : sum;
> > > +}
> > > +
> > > +static long get_mg_ctime_swaps(void)
> > > +{
> > > + int i;
> > > + long sum = 0;
> > > + for_each_possible_cpu(i)
> > > + sum += per_cpu(mg_ctime_swaps, i);
> > > + return sum < 0 ? 0 : sum;
> > > +}
> > > +
> > > long get_nr_dirty_inodes(void)
> > > {
> > > /* not actually dirty inodes, but a wild approximation */
> > > @@ -2655,6 +2697,7 @@ struct timespec64
> > > inode_set_ctime_current(struct inode *inode)
> > >
> > > /* Get a fine-grained time */
> > > fine = ktime_get();
> > > + this_cpu_inc(mg_fine_stamps);
> > >
> > > /*
> > > * If the cmpxchg works, we take the new
> > > floor value. If
> > > @@ -2663,11 +2706,14 @@ struct timespec64
> > > inode_set_ctime_current(struct inode *inode)
> > > * as good, so keep it.
> > > */
> > > old = floor;
> > > - if (!atomic64_try_cmpxchg(&ctime_floor,
> > > &old, fine))
> > > + if (atomic64_try_cmpxchg(&ctime_floor,
> > > &old, fine))
> > > + this_cpu_inc(mg_floor_swaps);
> > > + else
> > > fine = old;
> > > now = ktime_mono_to_real(fine);
> > > }
> > > }
> > > + this_cpu_inc(mg_ctime_updates);
> > > now_ts = timestamp_truncate(ktime_to_timespec64(now),
> > > inode);
> > > cur = cns;
> > >
> > > @@ -2682,6 +2728,7 @@ struct timespec64
> > > inode_set_ctime_current(struct inode *inode)
> > > /* If swap occurred, then we're (mostly) done */
> > > inode->i_ctime_sec = now_ts.tv_sec;
> > > trace_ctime_ns_xchg(inode, cns, now_ts.tv_nsec,
> > > cur);
> > > + this_cpu_inc(mg_ctime_swaps);
> > > } else {
> > > /*
> > > * Was the change due to someone marking the old
> > > ctime QUERIED?
> > > @@ -2751,3 +2798,24 @@ umode_t mode_strip_sgid(struct mnt_idmap
> > > *idmap,
> > > return mode & ~S_ISGID;
> > > }
> > > EXPORT_SYMBOL(mode_strip_sgid);
> > > +
> > >
Re: [PATCH v6 3/9] fs: add percpu counters for significant multigrain timestamp events
On Mon, Jul 15, 2024 at 03:53:42PM -0400, Jeff Layton wrote:
> On Mon, 2024-07-15 at 11:32 -0700, Darrick J. Wong wrote:
> > On Mon, Jul 15, 2024 at 08:48:54AM -0400, Jeff Layton wrote:
> > > Four percpu counters for counting various stats around mgtimes, and
> > > a
> > > new debugfs file for displaying them:
> > >
> > > - number of attempted ctime updates
> > > - number of successful i_ctime_nsec swaps
> > > - number of fine-grained timestamp fetches
> > > - number of floor value swaps
> > >
> > > Reviewed-by: Josef Bacik
> > > Signed-off-by: Jeff Layton
> > > ---
> > > fs/inode.c | 70
> > > +-
> > > 1 file changed, 69 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/fs/inode.c b/fs/inode.c
> > > index 869994285e87..fff844345c35 100644
> > > --- a/fs/inode.c
> > > +++ b/fs/inode.c
> > > @@ -21,6 +21,8 @@
> > > #include
> > > #include
> > > #include
> > > +#include
> > > +#include
> > > #include
> > > #define CREATE_TRACE_POINTS
> > > #include
> > > @@ -80,6 +82,10 @@ EXPORT_SYMBOL(empty_aops);
> > >
> > > static DEFINE_PER_CPU(unsigned long, nr_inodes);
> > > static DEFINE_PER_CPU(unsigned long, nr_unused);
> > > +static DEFINE_PER_CPU(unsigned long, mg_ctime_updates);
> > > +static DEFINE_PER_CPU(unsigned long, mg_fine_stamps);
> > > +static DEFINE_PER_CPU(unsigned long, mg_floor_swaps);
> > > +static DEFINE_PER_CPU(unsigned long, mg_ctime_swaps);
> >
> > Should this all get switched off if CONFIG_DEBUG_FS=n?
> >
> > --D
> >
>
> Sure, why not. That's simple enough to do.
>
> I pushed an updated mgtime branch to my git tree. Here's the updated
> patch that's the only difference:
>
>
> https://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux.git/commit/?h=mgtime&id=ee7fe6e9c0598754861c8620230f15f3de538ca5
>
> Seems to build OK both with and without CONFIG_DEBUG_FS.
LGTM,
Reviewed-by: Darrick J. Wong
Thank you for your work on all this multigrain stuff. :)
--D
>
> > >
> > > static struct kmem_cache *inode_cachep __ro_after_init;
> > >
> > > @@ -101,6 +107,42 @@ static inline long get_nr_inodes_unused(void)
> > > return sum < 0 ? 0 : sum;
> > > }
> > >
> > > +static long get_mg_ctime_updates(void)
> > > +{
> > > + int i;
> > > + long sum = 0;
> > > + for_each_possible_cpu(i)
> > > + sum += per_cpu(mg_ctime_updates, i);
> > > + return sum < 0 ? 0 : sum;
> > > +}
> > > +
> > > +static long get_mg_fine_stamps(void)
> > > +{
> > > + int i;
> > > + long sum = 0;
> > > + for_each_possible_cpu(i)
> > > + sum += per_cpu(mg_fine_stamps, i);
> > > + return sum < 0 ? 0 : sum;
> > > +}
> > > +
> > > +static long get_mg_floor_swaps(void)
> > > +{
> > > + int i;
> > > + long sum = 0;
> > > + for_each_possible_cpu(i)
> > > + sum += per_cpu(mg_floor_swaps, i);
> > > + return sum < 0 ? 0 : sum;
> > > +}
> > > +
> > > +static long get_mg_ctime_swaps(void)
> > > +{
> > > + int i;
> > > + long sum = 0;
> > > + for_each_possible_cpu(i)
> > > + sum += per_cpu(mg_ctime_swaps, i);
> > > + return sum < 0 ? 0 : sum;
> > > +}
> > > +
> > > long get_nr_dirty_inodes(void)
> > > {
> > > /* not actually dirty inodes, but a wild approximation */
> > > @@ -2655,6 +2697,7 @@ struct timespec64
> > > inode_set_ctime_current(struct inode *inode)
> > >
> > > /* Get a fine-grained time */
> > > fine = ktime_get();
> > > + this_cpu_inc(mg_fine_stamps);
> > >
> > > /*
> > > * If the cmpxchg works, we take the new
> > > floor value. If
> > > @@ -2663,11 +2706,14 @@ struct timespec64
> > > inode_set_ctime_current(struct inode *inode)
> > > * as good, so keep it.
> > > */
> > > old = floor;
> > > - if (!atomic64_try_cmpxchg(&ctime_floor,
> > > &old, fine))
> > > + if (atomic64_try_cmpxchg(&ctime_floor,
> > > &old, fine))
> > > + this_cpu_inc(mg_floor_swaps);
> > > + else
> > > fine = old;
> > > now = ktime_mono_to_real(fine);
> > > }
> > > }
> > > + this_cpu_inc(mg_ctime_updates);
> > > now_ts = timestamp_truncate(ktime_to_timespec64(now),
> > > inode);
> > > cur = cns;
> > >
> > > @@ -2682,6 +2728,7 @@ struct timespec64
> > > inode_set_ctime_current(struct inode *inode)
> > > /* If swap occurred, then we're (mostly) done */
> > > inode->i_ctime_sec = now_ts.tv_sec;
> > > trace_ctime_ns_xchg(inode, cns, now_ts.tv_nsec,
> > > cur);
> > > + this_cpu_inc(mg_ctime_swaps);
> > > } else {
> > > /*
> > > * Was the change due to someone marking the old
> > > ctime QUERIED?
> > > @@ -2751,3 +2798,24 @@ umode_t mode_strip_sgid(struct mnt_idmap
> > > *idmap,
> > > return mode & ~S_ISGID;
> > > }
> > > EXPORT_SYMBOL(mode_strip_sgid);
> > > +
> > > +static int
Re: [PATCH v6 3/9] fs: add percpu counters for significant multigrain timestamp events
On Mon, 2024-07-15 at 11:32 -0700, Darrick J. Wong wrote:
> On Mon, Jul 15, 2024 at 08:48:54AM -0400, Jeff Layton wrote:
> > Four percpu counters for counting various stats around mgtimes, and
> > a
> > new debugfs file for displaying them:
> >
> > - number of attempted ctime updates
> > - number of successful i_ctime_nsec swaps
> > - number of fine-grained timestamp fetches
> > - number of floor value swaps
> >
> > Reviewed-by: Josef Bacik
> > Signed-off-by: Jeff Layton
> > ---
> > fs/inode.c | 70
> > +-
> > 1 file changed, 69 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/inode.c b/fs/inode.c
> > index 869994285e87..fff844345c35 100644
> > --- a/fs/inode.c
> > +++ b/fs/inode.c
> > @@ -21,6 +21,8 @@
> > #include
> > #include
> > #include
> > +#include
> > +#include
> > #include
> > #define CREATE_TRACE_POINTS
> > #include
> > @@ -80,6 +82,10 @@ EXPORT_SYMBOL(empty_aops);
> >
> > static DEFINE_PER_CPU(unsigned long, nr_inodes);
> > static DEFINE_PER_CPU(unsigned long, nr_unused);
> > +static DEFINE_PER_CPU(unsigned long, mg_ctime_updates);
> > +static DEFINE_PER_CPU(unsigned long, mg_fine_stamps);
> > +static DEFINE_PER_CPU(unsigned long, mg_floor_swaps);
> > +static DEFINE_PER_CPU(unsigned long, mg_ctime_swaps);
>
> Should this all get switched off if CONFIG_DEBUG_FS=n?
>
> --D
>
Sure, why not. That's simple enough to do.
I pushed an updated mgtime branch to my git tree. Here's the updated
patch that's the only difference:
https://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux.git/commit/?h=mgtime&id=ee7fe6e9c0598754861c8620230f15f3de538ca5
Seems to build OK both with and without CONFIG_DEBUG_FS.
> >
> > static struct kmem_cache *inode_cachep __ro_after_init;
> >
> > @@ -101,6 +107,42 @@ static inline long get_nr_inodes_unused(void)
> > return sum < 0 ? 0 : sum;
> > }
> >
> > +static long get_mg_ctime_updates(void)
> > +{
> > + int i;
> > + long sum = 0;
> > + for_each_possible_cpu(i)
> > + sum += per_cpu(mg_ctime_updates, i);
> > + return sum < 0 ? 0 : sum;
> > +}
> > +
> > +static long get_mg_fine_stamps(void)
> > +{
> > + int i;
> > + long sum = 0;
> > + for_each_possible_cpu(i)
> > + sum += per_cpu(mg_fine_stamps, i);
> > + return sum < 0 ? 0 : sum;
> > +}
> > +
> > +static long get_mg_floor_swaps(void)
> > +{
> > + int i;
> > + long sum = 0;
> > + for_each_possible_cpu(i)
> > + sum += per_cpu(mg_floor_swaps, i);
> > + return sum < 0 ? 0 : sum;
> > +}
> > +
> > +static long get_mg_ctime_swaps(void)
> > +{
> > + int i;
> > + long sum = 0;
> > + for_each_possible_cpu(i)
> > + sum += per_cpu(mg_ctime_swaps, i);
> > + return sum < 0 ? 0 : sum;
> > +}
> > +
> > long get_nr_dirty_inodes(void)
> > {
> > /* not actually dirty inodes, but a wild approximation */
> > @@ -2655,6 +2697,7 @@ struct timespec64
> > inode_set_ctime_current(struct inode *inode)
> >
> > /* Get a fine-grained time */
> > fine = ktime_get();
> > + this_cpu_inc(mg_fine_stamps);
> >
> > /*
> > * If the cmpxchg works, we take the new
> > floor value. If
> > @@ -2663,11 +2706,14 @@ struct timespec64
> > inode_set_ctime_current(struct inode *inode)
> > * as good, so keep it.
> > */
> > old = floor;
> > - if (!atomic64_try_cmpxchg(&ctime_floor,
> > &old, fine))
> > + if (atomic64_try_cmpxchg(&ctime_floor,
> > &old, fine))
> > + this_cpu_inc(mg_floor_swaps);
> > + else
> > fine = old;
> > now = ktime_mono_to_real(fine);
> > }
> > }
> > + this_cpu_inc(mg_ctime_updates);
> > now_ts = timestamp_truncate(ktime_to_timespec64(now),
> > inode);
> > cur = cns;
> >
> > @@ -2682,6 +2728,7 @@ struct timespec64
> > inode_set_ctime_current(struct inode *inode)
> > /* If swap occurred, then we're (mostly) done */
> > inode->i_ctime_sec = now_ts.tv_sec;
> > trace_ctime_ns_xchg(inode, cns, now_ts.tv_nsec,
> > cur);
> > + this_cpu_inc(mg_ctime_swaps);
> > } else {
> > /*
> > * Was the change due to someone marking the old
> > ctime QUERIED?
> > @@ -2751,3 +2798,24 @@ umode_t mode_strip_sgid(struct mnt_idmap
> > *idmap,
> > return mode & ~S_ISGID;
> > }
> > EXPORT_SYMBOL(mode_strip_sgid);
> > +
> > +static int mgts_show(struct seq_file *s, void *p)
> > +{
> > + long ctime_updates = get_mg_ctime_updates();
> > + long ctime_swaps = get_mg_ctime_swaps();
> > + long fine_stamps = get_mg_fine_stamps();
> > + long floor_swaps = get_mg_floor_swaps();
> > +
> > + seq_printf(s, "%lu %lu %lu %lu\n",
> > + ctime_updates, ctime_swaps, fine_stamps,
> >
Re: [PATCH v6 3/9] fs: add percpu counters for significant multigrain timestamp events
On Mon, Jul 15, 2024 at 08:48:54AM -0400, Jeff Layton wrote:
> Four percpu counters for counting various stats around mgtimes, and a
> new debugfs file for displaying them:
>
> - number of attempted ctime updates
> - number of successful i_ctime_nsec swaps
> - number of fine-grained timestamp fetches
> - number of floor value swaps
>
> Reviewed-by: Josef Bacik
> Signed-off-by: Jeff Layton
> ---
> fs/inode.c | 70
> +-
> 1 file changed, 69 insertions(+), 1 deletion(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 869994285e87..fff844345c35 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -21,6 +21,8 @@
> #include
> #include
> #include
> +#include
> +#include
> #include
> #define CREATE_TRACE_POINTS
> #include
> @@ -80,6 +82,10 @@ EXPORT_SYMBOL(empty_aops);
>
> static DEFINE_PER_CPU(unsigned long, nr_inodes);
> static DEFINE_PER_CPU(unsigned long, nr_unused);
> +static DEFINE_PER_CPU(unsigned long, mg_ctime_updates);
> +static DEFINE_PER_CPU(unsigned long, mg_fine_stamps);
> +static DEFINE_PER_CPU(unsigned long, mg_floor_swaps);
> +static DEFINE_PER_CPU(unsigned long, mg_ctime_swaps);
Should this all get switched off if CONFIG_DEBUG_FS=n?
--D
>
> static struct kmem_cache *inode_cachep __ro_after_init;
>
> @@ -101,6 +107,42 @@ static inline long get_nr_inodes_unused(void)
> return sum < 0 ? 0 : sum;
> }
>
> +static long get_mg_ctime_updates(void)
> +{
> + int i;
> + long sum = 0;
> + for_each_possible_cpu(i)
> + sum += per_cpu(mg_ctime_updates, i);
> + return sum < 0 ? 0 : sum;
> +}
> +
> +static long get_mg_fine_stamps(void)
> +{
> + int i;
> + long sum = 0;
> + for_each_possible_cpu(i)
> + sum += per_cpu(mg_fine_stamps, i);
> + return sum < 0 ? 0 : sum;
> +}
> +
> +static long get_mg_floor_swaps(void)
> +{
> + int i;
> + long sum = 0;
> + for_each_possible_cpu(i)
> + sum += per_cpu(mg_floor_swaps, i);
> + return sum < 0 ? 0 : sum;
> +}
> +
> +static long get_mg_ctime_swaps(void)
> +{
> + int i;
> + long sum = 0;
> + for_each_possible_cpu(i)
> + sum += per_cpu(mg_ctime_swaps, i);
> + return sum < 0 ? 0 : sum;
> +}
> +
> long get_nr_dirty_inodes(void)
> {
> /* not actually dirty inodes, but a wild approximation */
> @@ -2655,6 +2697,7 @@ struct timespec64 inode_set_ctime_current(struct inode
> *inode)
>
> /* Get a fine-grained time */
> fine = ktime_get();
> + this_cpu_inc(mg_fine_stamps);
>
> /*
>* If the cmpxchg works, we take the new floor value. If
> @@ -2663,11 +2706,14 @@ struct timespec64 inode_set_ctime_current(struct
> inode *inode)
>* as good, so keep it.
>*/
> old = floor;
> - if (!atomic64_try_cmpxchg(&ctime_floor, &old, fine))
> + if (atomic64_try_cmpxchg(&ctime_floor, &old, fine))
> + this_cpu_inc(mg_floor_swaps);
> + else
> fine = old;
> now = ktime_mono_to_real(fine);
> }
> }
> + this_cpu_inc(mg_ctime_updates);
> now_ts = timestamp_truncate(ktime_to_timespec64(now), inode);
> cur = cns;
>
> @@ -2682,6 +2728,7 @@ struct timespec64 inode_set_ctime_current(struct inode
> *inode)
> /* If swap occurred, then we're (mostly) done */
> inode->i_ctime_sec = now_ts.tv_sec;
> trace_ctime_ns_xchg(inode, cns, now_ts.tv_nsec, cur);
> + this_cpu_inc(mg_ctime_swaps);
> } else {
> /*
>* Was the change due to someone marking the old ctime QUERIED?
> @@ -2751,3 +2798,24 @@ umode_t mode_strip_sgid(struct mnt_idmap *idmap,
> return mode & ~S_ISGID;
> }
> EXPORT_SYMBOL(mode_strip_sgid);
> +
> +static int mgts_show(struct seq_file *s, void *p)
> +{
> + long ctime_updates = get_mg_ctime_updates();
> + long ctime_swaps = get_mg_ctime_swaps();
> + long fine_stamps = get_mg_fine_stamps();
> + long floor_swaps = get_mg_floor_swaps();
> +
> + seq_printf(s, "%lu %lu %lu %lu\n",
> +ctime_updates, ctime_swaps, fine_stamps, floor_swaps);
> + return 0;
> +}
> +
> +DEFINE_SHOW_ATTRIBUTE(mgts);
> +
> +static int __init mg_debugfs_init(void)
> +{
> + debugfs_create_file("multigrain_timestamps", S_IFREG | S_IRUGO, NULL,
> NULL, &mgts_fops);
> + return 0;
> +}
> +late_initcall(mg_debugfs_init);
>
> --
> 2.45.2
>
>
