| Message ID | 20240212223029.30769-5-osalvador@suse.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | page_owner: print stacks and their outstanding allocations | expand |
On Mon, 12 Feb 2024 at 23:29, Oscar Salvador <osalvador@suse.de> wrote: > > We want to be able to filter out the stacks based on a threshold we can > can tune. > By writing to 'set_threshold' file, we can adjust the threshold value. > > Signed-off-by: Oscar Salvador <osalvador@suse.de> > --- > mm/page_owner.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) > > diff --git a/mm/page_owner.c b/mm/page_owner.c > index 3e4b7cd7c8f8..c4f9e5506e93 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -832,15 +832,18 @@ static void *stack_next(struct seq_file *m, void *v, loff_t *ppos) > return stack; > } > > +static unsigned long page_owner_stack_threshold; > + > static int stack_print(struct seq_file *m, void *v) > { > char *buf; > int ret = 0; > struct stack *stack = v; > struct stack_record *stack_record = stack->stack_record; > + int stack_count = refcount_read(&stack_record->count); > > if (!stack_record->size || stack_record->size < 0 || > - refcount_read(&stack_record->count) < 2) > + stack_count < 2 || stack_count < page_owner_stack_threshold) > return 0; > > buf = kzalloc(PAGE_SIZE, GFP_KERNEL); > @@ -851,7 +854,7 @@ static int stack_print(struct seq_file *m, void *v) > goto out; > > scnprintf(buf + ret, PAGE_SIZE - ret, "stack_count: %d\n\n", > - refcount_read(&stack_record->count)); > + stack_count); > > seq_printf(m, buf); > seq_puts(m, "\n\n"); > @@ -884,6 +887,21 @@ static const struct file_operations page_owner_stack_operations = { > .release = seq_release, > }; > > +static int page_owner_threshold_get(void *data, u64 *val) > +{ > + *val = page_owner_stack_threshold; > + return 0; > +} > + > +static int page_owner_threshold_set(void *data, u64 val) > +{ > + page_owner_stack_threshold = val; This could be written concurrently, so to avoid data races, you can use WRITE_ONCE(page_owner_stack_threshold, val) and use READ_ONCE(page_owner_stack_threshold) where it's read. > + return 0; > +} > + > +DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get, > + &page_owner_threshold_set, "%llu"); > + > static int __init pageowner_init(void) > { > struct dentry *dir; > @@ -898,6 +916,8 @@ static int __init pageowner_init(void) > dir = debugfs_create_dir("page_owner_stacks", NULL); > debugfs_create_file("show_stacks", 0400, dir, NULL, > &page_owner_stack_operations); > + debugfs_create_file("set_threshold", 0600, dir, NULL, > + &proc_page_owner_threshold); > > return 0; > } > -- > 2.43.0 >
On Mon, 12 Feb 2024 at 23:29, Oscar Salvador <osalvador@suse.de> wrote: > > We want to be able to filter out the stacks based on a threshold we can > can tune. > By writing to 'set_threshold' file, we can adjust the threshold value. > > Signed-off-by: Oscar Salvador <osalvador@suse.de> > --- > mm/page_owner.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) > > diff --git a/mm/page_owner.c b/mm/page_owner.c > index 3e4b7cd7c8f8..c4f9e5506e93 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -832,15 +832,18 @@ static void *stack_next(struct seq_file *m, void *v, loff_t *ppos) > return stack; > } > > +static unsigned long page_owner_stack_threshold; > + > static int stack_print(struct seq_file *m, void *v) > { > char *buf; > int ret = 0; > struct stack *stack = v; > struct stack_record *stack_record = stack->stack_record; > + int stack_count = refcount_read(&stack_record->count); > > if (!stack_record->size || stack_record->size < 0 || > - refcount_read(&stack_record->count) < 2) > + stack_count < 2 || stack_count < page_owner_stack_threshold) > return 0; > > buf = kzalloc(PAGE_SIZE, GFP_KERNEL); > @@ -851,7 +854,7 @@ static int stack_print(struct seq_file *m, void *v) > goto out; > > scnprintf(buf + ret, PAGE_SIZE - ret, "stack_count: %d\n\n", > - refcount_read(&stack_record->count)); > + stack_count); > > seq_printf(m, buf); > seq_puts(m, "\n\n"); > @@ -884,6 +887,21 @@ static const struct file_operations page_owner_stack_operations = { > .release = seq_release, > }; > > +static int page_owner_threshold_get(void *data, u64 *val) > +{ > + *val = page_owner_stack_threshold; > + return 0; > +} > + > +static int page_owner_threshold_set(void *data, u64 val) > +{ > + page_owner_stack_threshold = val; > + return 0; > +} > + > +DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get, > + &page_owner_threshold_set, "%llu"); > + > static int __init pageowner_init(void) > { > struct dentry *dir; > @@ -898,6 +916,8 @@ static int __init pageowner_init(void) > dir = debugfs_create_dir("page_owner_stacks", NULL); > debugfs_create_file("show_stacks", 0400, dir, NULL, > &page_owner_stack_operations); > + debugfs_create_file("set_threshold", 0600, dir, NULL, > + &proc_page_owner_threshold); Can't you also read from "set_threshold", so the name "set_threshold" is misleading. Why not just "threshold"?
On Tue, Feb 13, 2024 at 09:44:47AM +0100, Marco Elver wrote: > On Mon, 12 Feb 2024 at 23:29, Oscar Salvador <osalvador@suse.de> wrote: > > + debugfs_create_file("set_threshold", 0600, dir, NULL, > > + &proc_page_owner_threshold); > > Can't you also read from "set_threshold", so the name "set_threshold" > is misleading. Why not just "threshold"? Yes, it can also be read. I guess I was too focused on the set part. I will rename that one, plus add the {READ,WRITE}_ONCE. Thanks!
On 2/13/24 10:21, Oscar Salvador wrote: > On Tue, Feb 13, 2024 at 09:44:47AM +0100, Marco Elver wrote: >> On Mon, 12 Feb 2024 at 23:29, Oscar Salvador <osalvador@suse.de> >> wrote: >>> + debugfs_create_file("set_threshold", 0600, dir, NULL, + >>> &proc_page_owner_threshold); >> >> Can't you also read from "set_threshold", so the name "set_threshold" >> is misleading. Why not just "threshold"? > > Yes, it can also be read. I guess I was too focused on the set part. Maybe name it "count_threshold" so it's more clear of whate exactly it's the threshold of? > I will rename that one, plus add the {READ,WRITE}_ONCE. > > Thanks! >
diff --git a/mm/page_owner.c b/mm/page_owner.c index 3e4b7cd7c8f8..c4f9e5506e93 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -832,15 +832,18 @@ static void *stack_next(struct seq_file *m, void *v, loff_t *ppos) return stack; } +static unsigned long page_owner_stack_threshold; + static int stack_print(struct seq_file *m, void *v) { char *buf; int ret = 0; struct stack *stack = v; struct stack_record *stack_record = stack->stack_record; + int stack_count = refcount_read(&stack_record->count); if (!stack_record->size || stack_record->size < 0 || - refcount_read(&stack_record->count) < 2) + stack_count < 2 || stack_count < page_owner_stack_threshold) return 0; buf = kzalloc(PAGE_SIZE, GFP_KERNEL); @@ -851,7 +854,7 @@ static int stack_print(struct seq_file *m, void *v) goto out; scnprintf(buf + ret, PAGE_SIZE - ret, "stack_count: %d\n\n", - refcount_read(&stack_record->count)); + stack_count); seq_printf(m, buf); seq_puts(m, "\n\n"); @@ -884,6 +887,21 @@ static const struct file_operations page_owner_stack_operations = { .release = seq_release, }; +static int page_owner_threshold_get(void *data, u64 *val) +{ + *val = page_owner_stack_threshold; + return 0; +} + +static int page_owner_threshold_set(void *data, u64 val) +{ + page_owner_stack_threshold = val; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get, + &page_owner_threshold_set, "%llu"); + static int __init pageowner_init(void) { struct dentry *dir; @@ -898,6 +916,8 @@ static int __init pageowner_init(void) dir = debugfs_create_dir("page_owner_stacks", NULL); debugfs_create_file("show_stacks", 0400, dir, NULL, &page_owner_stack_operations); + debugfs_create_file("set_threshold", 0600, dir, NULL, + &proc_page_owner_threshold); return 0; }
We want to be able to filter out the stacks based on a threshold we can can tune. By writing to 'set_threshold' file, we can adjust the threshold value. Signed-off-by: Oscar Salvador <osalvador@suse.de> --- mm/page_owner.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-)