| Message ID | 20220404164112.18372-5-vbabka@suse.cz (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | SLUB debugfs improvements based on stackdepot | expand |
On Mon, 4 Apr 2022, Vlastimil Babka wrote: > From: Oliver Glitta <glittao@gmail.com> > > Aggregate objects in slub cache by unique stack trace in addition to > caller address when producing contents of debugfs files alloc_traces and > free_traces in debugfs. Also add the stack traces to the debugfs output. > This makes it much more useful to e.g. debug memory leaks. > > Signed-off-by: Oliver Glitta <glittao@gmail.com> > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > Reviewed-and-tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > --- > mm/slub.c | 28 ++++++++++++++++++++++++++-- > 1 file changed, 26 insertions(+), 2 deletions(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 98c1450c23f0..f2e550e1adf0 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -5064,6 +5064,7 @@ EXPORT_SYMBOL(validate_slab_cache); > */ > > struct location { > + depot_stack_handle_t handle; > unsigned long count; > unsigned long addr; > long long sum_time; > @@ -5116,9 +5117,13 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, > { > long start, end, pos; > struct location *l; > - unsigned long caddr; > + unsigned long caddr, chandle; > unsigned long age = jiffies - track->when; > + depot_stack_handle_t handle = 0; > > +#ifdef CONFIG_STACKDEPOT > + handle = READ_ONCE(track->handle); > +#endif > start = -1; > end = t->count; > > @@ -5133,7 +5138,8 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, > break; > > caddr = t->loc[pos].addr; > - if (track->addr == caddr) { > + chandle = t->loc[pos].handle; > + if ((track->addr == caddr) && (handle == chandle)) { > > l = &t->loc[pos]; > l->count++; > @@ -5158,6 +5164,8 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, > > if (track->addr < caddr) > end = pos; > + else if (track->addr == caddr && handle < chandle) > + end = pos; > else > start = pos; > } Does this need to properly handle the case where handle == NULL? > @@ -5180,6 +5188,7 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, > l->max_time = age; > l->min_pid = track->pid; > l->max_pid = track->pid; > + l->handle = handle; > cpumask_clear(to_cpumask(l->cpus)); > cpumask_set_cpu(track->cpu, to_cpumask(l->cpus)); > nodes_clear(l->nodes); > @@ -6089,6 +6098,21 @@ static int slab_debugfs_show(struct seq_file *seq, void *v) > seq_printf(seq, " nodes=%*pbl", > nodemask_pr_args(&l->nodes)); > > +#ifdef CONFIG_STACKDEPOT > + { > + depot_stack_handle_t handle; > + unsigned long *entries; > + unsigned int nr_entries, j; > + > + handle = READ_ONCE(l->handle); > + if (handle) { > + nr_entries = stack_depot_fetch(handle, &entries); > + seq_puts(seq, "\n"); > + for (j = 0; j < nr_entries; j++) > + seq_printf(seq, " %pS\n", (void *)entries[j]); > + } > + } > +#endif > seq_puts(seq, "\n"); > } > > -- > 2.35.1 > >
On 4/5/22 23:40, David Rientjes wrote: >> @@ -5116,9 +5117,13 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, >> { >> long start, end, pos; >> struct location *l; >> - unsigned long caddr; >> + unsigned long caddr, chandle; >> unsigned long age = jiffies - track->when; >> + depot_stack_handle_t handle = 0; >> >> +#ifdef CONFIG_STACKDEPOT >> + handle = READ_ONCE(track->handle); >> +#endif >> start = -1; >> end = t->count; >> >> @@ -5133,7 +5138,8 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, >> break; >> >> caddr = t->loc[pos].addr; >> - if (track->addr == caddr) { >> + chandle = t->loc[pos].handle; >> + if ((track->addr == caddr) && (handle == chandle)) { >> >> l = &t->loc[pos]; >> l->count++; >> @@ -5158,6 +5164,8 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, >> >> if (track->addr < caddr) >> end = pos; >> + else if (track->addr == caddr && handle < chandle) >> + end = pos; >> else >> start = pos; >> } > > Does this need to properly handle the case where handle == NULL? Hm I can't think of how much more properly is possible. If objects have same track->addr (which is the immediate caller) and also same NULL handle, they will be counted together. I think it's the best we can do?
diff --git a/mm/slub.c b/mm/slub.c index 98c1450c23f0..f2e550e1adf0 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5064,6 +5064,7 @@ EXPORT_SYMBOL(validate_slab_cache); */ struct location { + depot_stack_handle_t handle; unsigned long count; unsigned long addr; long long sum_time; @@ -5116,9 +5117,13 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, { long start, end, pos; struct location *l; - unsigned long caddr; + unsigned long caddr, chandle; unsigned long age = jiffies - track->when; + depot_stack_handle_t handle = 0; +#ifdef CONFIG_STACKDEPOT + handle = READ_ONCE(track->handle); +#endif start = -1; end = t->count; @@ -5133,7 +5138,8 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, break; caddr = t->loc[pos].addr; - if (track->addr == caddr) { + chandle = t->loc[pos].handle; + if ((track->addr == caddr) && (handle == chandle)) { l = &t->loc[pos]; l->count++; @@ -5158,6 +5164,8 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, if (track->addr < caddr) end = pos; + else if (track->addr == caddr && handle < chandle) + end = pos; else start = pos; } @@ -5180,6 +5188,7 @@ static int add_location(struct loc_track *t, struct kmem_cache *s, l->max_time = age; l->min_pid = track->pid; l->max_pid = track->pid; + l->handle = handle; cpumask_clear(to_cpumask(l->cpus)); cpumask_set_cpu(track->cpu, to_cpumask(l->cpus)); nodes_clear(l->nodes); @@ -6089,6 +6098,21 @@ static int slab_debugfs_show(struct seq_file *seq, void *v) seq_printf(seq, " nodes=%*pbl", nodemask_pr_args(&l->nodes)); +#ifdef CONFIG_STACKDEPOT + { + depot_stack_handle_t handle; + unsigned long *entries; + unsigned int nr_entries, j; + + handle = READ_ONCE(l->handle); + if (handle) { + nr_entries = stack_depot_fetch(handle, &entries); + seq_puts(seq, "\n"); + for (j = 0; j < nr_entries; j++) + seq_printf(seq, " %pS\n", (void *)entries[j]); + } + } +#endif seq_puts(seq, "\n"); }