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);
return 0;
}
--
2.43.0On 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!
--
Oscar Salvador
SUSE Labs
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!
>
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
>
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