On 13 Nov 2020, at 19:23, Roman Gushchin wrote: > On Wed, Nov 11, 2020 at 03:40:04PM -0500, Zi Yan wrote: >> From: Zi Yan <[email protected]> >> >> It reads thp_nr_pages and splits to provided new_nr. It prepares for >> upcoming changes to support split huge page to any lower order. >> >> Signed-off-by: Zi Yan <[email protected]> >> --- >> include/linux/memcontrol.h | 5 +++-- >> mm/huge_memory.c | 2 +- >> mm/memcontrol.c | 4 ++-- >> 3 files changed, 6 insertions(+), 5 deletions(-) >> >> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h >> index 0f4dd7829fb2..b3bac79ceed6 100644 >> --- a/include/linux/memcontrol.h >> +++ b/include/linux/memcontrol.h >> @@ -1105,7 +1105,7 @@ static inline void memcg_memory_event_mm(struct >> mm_struct *mm, >> } >> >> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >> -void mem_cgroup_split_huge_fixup(struct page *head); >> +void mem_cgroup_split_huge_fixup(struct page *head, unsigned int new_nr); >> #endif >> >> #else /* CONFIG_MEMCG */ >> @@ -1451,7 +1451,8 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t >> *pgdat, int order, >> return 0; >> } >> >> -static inline void mem_cgroup_split_huge_fixup(struct page *head) >> +static inline void mem_cgroup_split_huge_fixup(struct page *head, >> + unsigned int new_nr) >> { >> } >> >> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >> index c4fead5ead31..f599f5b9bf7f 100644 >> --- a/mm/huge_memory.c >> +++ b/mm/huge_memory.c >> @@ -2429,7 +2429,7 @@ static void __split_huge_page(struct page *page, >> struct list_head *list, >> lruvec = mem_cgroup_page_lruvec(head, pgdat); >> >> /* complete memcg works before add pages to LRU */ >> - mem_cgroup_split_huge_fixup(head); >> + mem_cgroup_split_huge_fixup(head, 1); >> >> if (PageAnon(head) && PageSwapCache(head)) { >> swp_entry_t entry = { .val = page_private(head) }; >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> index 33f632689cee..e9705ba6bbcc 100644 >> --- a/mm/memcontrol.c >> +++ b/mm/memcontrol.c >> @@ -3247,7 +3247,7 @@ void obj_cgroup_uncharge(struct obj_cgroup *objcg, >> size_t size) >> * Because tail pages are not marked as "used", set it. We're under >> * pgdat->lru_lock and migration entries setup in all page mappings. >> */ >> -void mem_cgroup_split_huge_fixup(struct page *head) >> +void mem_cgroup_split_huge_fixup(struct page *head, unsigned int new_nr) > > I'd go with unsigned int new_order, then it's obvious that we can split > the original page without any leftovers.
Makes sense. Will change it. > > Other than that the patch looks good! > Acked-by: Roman Gushchin <[email protected]> Thanks. >> { >> struct mem_cgroup *memcg = page_memcg(head); >> int i; >> @@ -3255,7 +3255,7 @@ void mem_cgroup_split_huge_fixup(struct page *head) >> if (mem_cgroup_disabled()) >> return; >> >> - for (i = 1; i < thp_nr_pages(head); i++) { >> + for (i = new_nr; i < thp_nr_pages(head); i += new_nr) { >> css_get(&memcg->css); >> head[i].memcg_data = (unsigned long)memcg; >> } >> -- >> 2.28.0 >> — Best Regards, Yan Zi
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