lkml.org 
[lkml]   [2020]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v1 3/4] mm: introduce page memcg flags
On Tue, Sep 22, 2020 at 01:36:59PM -0700, Roman Gushchin wrote:
> @@ -422,7 +421,13 @@ static inline void clear_page_mem_cgroup(struct page *page)
> */
> static inline struct obj_cgroup **page_obj_cgroups(struct page *page)
> {
> - return (struct obj_cgroup **)(page->memcg_data & ~0x1UL);
> + unsigned long memcg_data = page->memcg_data;
> +
> + VM_BUG_ON_PAGE(memcg_data && !test_bit(PG_MEMCG_OBJ_CGROUPS,
> + &memcg_data), page);
> + __clear_bit(PG_MEMCG_OBJ_CGROUPS, &memcg_data);
> +
> + return (struct obj_cgroup **)memcg_data;

Slab allocations set up page->memcg_data locklessly, right? AFAICS,
the page_objcg lookup functions all need READ_ONCE() loads.

\
 
 \ /
  Last update: 2020-09-24 22:08    [W:0.695 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site