From: Oscar Salvador <osalvador@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
Eric Dumazet <edumazet@google.com>,
Waiman Long <longman@redhat.com>,
Suren Baghdasaryan <surenb@google.com>,
Marco Elver <elver@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Alexander Potapenko <glider@google.com>,
Oscar Salvador <osalvador@suse.de>
Subject: [PATCH v2 2/3] mm, page_owner: Add page_owner_stacks file to print out only stacks and their counter
Date: Mon, 5 Sep 2022 05:10:11 +0200 [thread overview]
Message-ID: <20220905031012.4450-3-osalvador@suse.de> (raw)
In-Reply-To: <20220905031012.4450-1-osalvador@suse.de>
We might be only interested in knowing about stacks <-> count
relationship, so instead of having to fiddle with page_owner
output and screen through pfns, let us add a new file called
'page_owner_stacks' that does just that.
By cating such file, we will get all the stacktraces followed by
its counter, so we can have a more global view.
Signed-off-by: Oscar Salvador <osalvador@suse.de>
---
include/linux/stackdepot.h | 1 +
lib/stackdepot.c | 40 ++++++++++++++++++++++++++++++++++++++
mm/page_owner.c | 25 ++++++++++++++++++++++++
3 files changed, 66 insertions(+)
diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h
index 4e3a88f135ee..19d3f8295df8 100644
--- a/include/linux/stackdepot.h
+++ b/include/linux/stackdepot.h
@@ -25,6 +25,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries,
gfp_t gfp_flags, bool can_alloc,
enum stack_depot_action action);
void stack_depot_dec_count(depot_stack_handle_t handle);
+int stack_depot_print_stacks_threshold(char *buf, size_t size, loff_t *pos);
/*
* Every user of stack depot has to call stack_depot_init() during its own init
diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index a806ef58a385..a198b2dbe3fb 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -565,3 +565,43 @@ depot_stack_handle_t stack_depot_save_action(unsigned long *entries,
return __stack_depot_save(entries, nr_entries, alloc_flags, true, action);
}
EXPORT_SYMBOL_GPL(stack_depot_save_action);
+
+int stack_depot_print_stacks_threshold(char *buf, size_t size, loff_t *pos)
+{
+ int i = *pos, ret = 0;
+ struct stack_record **stacks, *stack;
+ static struct stack_record *last = NULL;
+ unsigned long stack_table_entries = stack_hash_mask + 1;
+
+ /* Continue from the last stack if we have one */
+ if (last) {
+ stack = last->next;
+ } else {
+new_table:
+ stacks = &stack_table[i];
+ stack = (struct stack_record *)stacks;
+ }
+
+ for (; stack; stack = stack->next) {
+ if (!stack->size || stack->size < 0 ||
+ stack->size > size || stack->handle.valid != 1 ||
+ refcount_read(&stack->count) < 1)
+ continue;
+
+ ret += stack_trace_snprint(buf, size, stack->entries, stack->size, 0);
+ ret += scnprintf(buf + ret, size - ret, "stack count: %d\n\n",
+ refcount_read(&stack->count));
+ last = stack;
+ return ret;
+ }
+
+ i++;
+ *pos = i;
+ last = NULL;
+
+ /* Keep looking all tables for valid stacks */
+ if (i < stack_table_entries)
+ goto new_table;
+
+ return 0;
+}
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 8730f377fa91..d88e6b4aefa0 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -664,6 +664,29 @@ static void init_early_allocated_pages(void)
init_zones_in_node(pgdat);
}
+static ssize_t read_page_owner_stacks(struct file *file, char __user *buf,
+ size_t count, loff_t *pos)
+{
+ char *kbuf;
+ int ret = 0;
+
+ count = min_t(size_t, count, PAGE_SIZE);
+ kbuf = kmalloc(count, GFP_KERNEL);
+ if (!kbuf)
+ return -ENOMEM;
+
+ ret += stack_depot_print_stacks_threshold(kbuf, count, pos);
+ if (copy_to_user(buf, kbuf, ret))
+ ret = -EFAULT;
+
+ kfree(kbuf);
+ return ret;
+}
+
+static const struct file_operations proc_page_owner_stacks = {
+ .read = read_page_owner_stacks,
+};
+
static const struct file_operations proc_page_owner_operations = {
.read = read_page_owner,
};
@@ -677,6 +700,8 @@ static int __init pageowner_init(void)
debugfs_create_file("page_owner", 0400, NULL, NULL,
&proc_page_owner_operations);
+ debugfs_create_file("page_owner_stacks", 0400, NULL, NULL,
+ &proc_page_owner_stacks);
return 0;
}
--
2.35.3
next prev parent reply other threads:[~2022-09-05 3:11 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-05 3:10 [PATCH v2 0/3] page_owner: print stacks and their counter Oscar Salvador
2022-09-05 3:10 ` [PATCH v2 1/3] lib/stackdepot: Add a refcount field in stack_record Oscar Salvador
2022-09-05 20:57 ` Andrey Konovalov
2022-09-06 3:54 ` Oscar Salvador
2022-09-10 22:33 ` Andrey Konovalov
2022-09-19 15:01 ` Vlastimil Babka
2022-09-05 3:10 ` Oscar Salvador [this message]
2022-09-05 12:57 ` [PATCH v2 2/3] mm, page_owner: Add page_owner_stacks file to print out only stacks and their counter Marco Elver
2022-09-05 13:00 ` Marco Elver
2022-09-06 7:43 ` Oscar Salvador
2022-09-06 8:35 ` Marco Elver
2022-09-07 4:00 ` Oscar Salvador
2022-09-07 7:14 ` Marco Elver
2022-09-08 3:32 ` Oscar Salvador
2022-09-08 5:31 ` Marco Elver
2022-09-05 22:20 ` kernel test robot
2022-09-05 3:10 ` [PATCH v2 3/3] mm,page_owner: Filter out stacks by a threshold counter Oscar Salvador
2022-09-05 10:51 ` Ammar Faizi
2022-09-05 11:31 ` Michal Hocko
2022-09-05 11:54 ` Ammar Faizi
2022-09-05 12:02 ` Michal Hocko
2022-09-05 12:42 ` Ammar Faizi
2022-09-19 15:23 ` Vlastimil Babka
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