Re: [PATCH -mm -v3 1/6] mm, swap: Add swap cache statistics sysfs interface
Hi, Rik, Rik van Riel writes: > On Tue, 2017-07-25 at 09:51 +0800, Huang, Ying wrote: >> From: Huang Ying >> >> The swap cache stats could be gotten only via sysrq, which isn't >> convenient in some situation. So the sysfs interface of swap cache >> stats is added for that. The added sysfs directories/files are as >> follow, >> >> /sys/kernel/mm/swap >> /sys/kernel/mm/swap/cache_find_total >> /sys/kernel/mm/swap/cache_find_success >> /sys/kernel/mm/swap/cache_add >> /sys/kernel/mm/swap/cache_del >> /sys/kernel/mm/swap/cache_pages >> > What is the advantage of this vs new fields in > /proc/vmstat, which is where most of the VM > statistics seem to live? As proposed by Andrew, will use debugfs for them, because they are mostly developer related. Best Regards, Huang, Ying
Re: [PATCH -mm -v3 1/6] mm, swap: Add swap cache statistics sysfs interface
Andrew Morton writes: > On Tue, 25 Jul 2017 09:51:46 +0800 "Huang, Ying" wrote: > >> The swap cache stats could be gotten only via sysrq, which isn't >> convenient in some situation. So the sysfs interface of swap cache >> stats is added for that. The added sysfs directories/files are as >> follow, >> >> /sys/kernel/mm/swap >> /sys/kernel/mm/swap/cache_find_total >> /sys/kernel/mm/swap/cache_find_success >> /sys/kernel/mm/swap/cache_add >> /sys/kernel/mm/swap/cache_del >> /sys/kernel/mm/swap/cache_pages > > We should document this somewhere. Documentation/ABI/ is the formal > place for sysfs files, but nobody will think to look there for VM > things, so perhaps place a pointer to the Documentation/ABI/ files > within Documentation/vm somewhere, only there isn't an appropriate > Documentation/vm file ;) > > Or just put all these things in debugfs. These are pretty specialized > things and appear to be developer-only files of short-term interest? Yes. Debugfs should be better place for these. Will update it in the next version. And I also introduced sysfs interface in [2/6] and [5/6] /sys/kernel/mm/swap/ra_hits /sys/kernel/mm/swap/ra_total /sys/kernel/mm/swap/vma_ra_enabled /sys/kernel/mm/swap/vma_ra_max_order Will add ABI document for them. Best Regards, Huang, Ying
Re: [PATCH -mm -v3 1/6] mm, swap: Add swap cache statistics sysfs interface
On Tue, 2017-07-25 at 09:51 +0800, Huang, Ying wrote: > From: Huang Ying > > The swap cache stats could be gotten only via sysrq, which isn't > convenient in some situation. So the sysfs interface of swap cache > stats is added for that. The added sysfs directories/files are as > follow, > > /sys/kernel/mm/swap > /sys/kernel/mm/swap/cache_find_total > /sys/kernel/mm/swap/cache_find_success > /sys/kernel/mm/swap/cache_add > /sys/kernel/mm/swap/cache_del > /sys/kernel/mm/swap/cache_pages > What is the advantage of this vs new fields in /proc/vmstat, which is where most of the VM statistics seem to live? -- All rights reversed signature.asc Description: This is a digitally signed message part
Re: [PATCH -mm -v3 1/6] mm, swap: Add swap cache statistics sysfs interface
On Tue, 25 Jul 2017 09:51:46 +0800 "Huang, Ying" wrote: > The swap cache stats could be gotten only via sysrq, which isn't > convenient in some situation. So the sysfs interface of swap cache > stats is added for that. The added sysfs directories/files are as > follow, > > /sys/kernel/mm/swap > /sys/kernel/mm/swap/cache_find_total > /sys/kernel/mm/swap/cache_find_success > /sys/kernel/mm/swap/cache_add > /sys/kernel/mm/swap/cache_del > /sys/kernel/mm/swap/cache_pages We should document this somewhere. Documentation/ABI/ is the formal place for sysfs files, but nobody will think to look there for VM things, so perhaps place a pointer to the Documentation/ABI/ files within Documentation/vm somewhere, only there isn't an appropriate Documentation/vm file ;) Or just put all these things in debugfs. These are pretty specialized things and appear to be developer-only files of short-term interest?
[PATCH -mm -v3 1/6] mm, swap: Add swap cache statistics sysfs interface
From: Huang Ying
The swap cache stats could be gotten only via sysrq, which isn't
convenient in some situation. So the sysfs interface of swap cache
stats is added for that. The added sysfs directories/files are as
follow,
/sys/kernel/mm/swap
/sys/kernel/mm/swap/cache_find_total
/sys/kernel/mm/swap/cache_find_success
/sys/kernel/mm/swap/cache_add
/sys/kernel/mm/swap/cache_del
/sys/kernel/mm/swap/cache_pages
Signed-off-by: "Huang, Ying"
Cc: Johannes Weiner
Cc: Minchan Kim
Cc: Rik van Riel
Cc: Shaohua Li
Cc: Hugh Dickins
Cc: Fengguang Wu
Cc: Tim Chen
Cc: Dave Hansen
---
mm/swap_state.c | 78 +
1 file changed, 78 insertions(+)
diff --git a/mm/swap_state.c b/mm/swap_state.c
index b68c93014f50..a13bbf504e93 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -561,3 +561,81 @@ void exit_swap_address_space(unsigned int type)
synchronize_rcu();
kvfree(spaces);
}
+
+#ifdef CONFIG_SYSFS
+static ssize_t swap_cache_pages_show(
+ struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%lu\n", total_swapcache_pages());
+}
+static struct kobj_attribute swap_cache_pages_attr =
+ __ATTR(cache_pages, 0444, swap_cache_pages_show, NULL);
+
+static ssize_t swap_cache_add_show(
+ struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%lu\n", swap_cache_info.add_total);
+}
+static struct kobj_attribute swap_cache_add_attr =
+ __ATTR(cache_add, 0444, swap_cache_add_show, NULL);
+
+static ssize_t swap_cache_del_show(
+ struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%lu\n", swap_cache_info.del_total);
+}
+static struct kobj_attribute swap_cache_del_attr =
+ __ATTR(cache_del, 0444, swap_cache_del_show, NULL);
+
+static ssize_t swap_cache_find_success_show(
+ struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%lu\n", swap_cache_info.find_success);
+}
+static struct kobj_attribute swap_cache_find_success_attr =
+ __ATTR(cache_find_success, 0444, swap_cache_find_success_show, NULL);
+
+static ssize_t swap_cache_find_total_show(
+ struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%lu\n", swap_cache_info.find_total);
+}
+static struct kobj_attribute swap_cache_find_total_attr =
+ __ATTR(cache_find_total, 0444, swap_cache_find_total_show, NULL);
+
+static struct attribute *swap_attrs[] = {
+ &swap_cache_pages_attr.attr,
+ &swap_cache_add_attr.attr,
+ &swap_cache_del_attr.attr,
+ &swap_cache_find_success_attr.attr,
+ &swap_cache_find_total_attr.attr,
+ NULL,
+};
+
+static struct attribute_group swap_attr_group = {
+ .attrs = swap_attrs,
+};
+
+static int __init swap_init_sysfs(void)
+{
+ int err;
+ struct kobject *swap_kobj;
+
+ swap_kobj = kobject_create_and_add("swap", mm_kobj);
+ if (!swap_kobj) {
+ pr_err("failed to create swap kobject\n");
+ return -ENOMEM;
+ }
+ err = sysfs_create_group(swap_kobj, &swap_attr_group);
+ if (err) {
+ pr_err("failed to register swap group\n");
+ goto delete_obj;
+ }
+ return 0;
+
+delete_obj:
+ kobject_put(swap_kobj);
+ return err;
+}
+subsys_initcall(swap_init_sysfs);
+#endif
--
2.13.2
