On 08.09.22 09:58, Muchun Song wrote:
The memory-notify-based approach aims to handle meory-less nodes, however, it just adds
the complexity of code as pointed by David in thread [1]. The handling of memory-less
nodes is introduced by commit 4faf8d950ec4 ("hugetlb: handle memory hot-plug events").
From its commit message, we cannot find any necessity of handling this case. So, we can
simply register/unregister sysfs entries in register_node/unregister_node to simlify the
code.
BTW, hotplug callback added because in hugetlb_register_all_nodes() we register sysfs
nodes only for N_MEMORY nodes, seeing commit 9b5e5d0fdc91, which said it was a preparation
for handling memory-less nodes via memory hotplug. Since we want to remove memory hotplug,
so make sure we only register per-node sysfs for online (N_ONLINE) nodes in
hugetlb_register_all_nodes().
https://lore.kernel.org/linux-mm/60933ffc-b850-976c-78a0-0ee6e0ea9ef0@xxxxxxxxxx/ [1]
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
v3:
- Fix 'struct node' is not declared reported by LTP.
v2:
- Move declaration of function related to hugetlb to hugetlb.h (David).
- Introduce hugetlb_sysfs_initialized() and call it from hugetlb_sysfs_init() (David).
- Move hugetlb_register_all_nodes() into hugetlb_sysfs_init() (David).
- Fix implicit-function-declaration reported by LKP.
- Register per-node sysfs for online (N_ONLINE) nodes instead of N_MEMORY (Aneesh).
drivers/base/node.c | 8 +++--
include/linux/hugetlb.h | 14 +++++++++
mm/hugetlb.c | 81 ++++++++++++++++++++++---------------------------
3 files changed, 57 insertions(+), 46 deletions(-)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3880,24 +3880,14 @@ static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
return 0;
}
-static void __init hugetlb_sysfs_init(void)
-{
- struct hstate *h;
- int err;
-
- hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
- if (!hugepages_kobj)
- return;
+#ifdef CONFIG_NUMA
+static bool hugetlb_sysfs_initialized __ro_after_init;
- for_each_hstate(h) {
- err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
- hstate_kobjs, &hstate_attr_group);
- if (err)
- pr_err("HugeTLB: Unable to add hstate %s", h->name);
- }
+static inline void hugetlb_mark_sysfs_initialized(void)
+{
+ hugetlb_sysfs_initialized = true;
}
Do we really need a separate function for this? Why not simply always
set that from hugetlb_sysfs_init() ?
I'm also not sure if we really want to optimize out one variable for
!CONFIG_NUMA.
Anyhow, in general
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David / dhildenb
