From: Johannes Weiner <hannes@cmpxchg.org>
To: Roman Gushchin <guro@fb.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Shakeel Butt <shakeelb@google.com>,
Michal Hocko <mhocko@kernel.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kernel-team@fb.com
Subject: Re: [PATCH v4 3/4] mm: introduce page memcg flags
Date: Thu, 1 Oct 2020 09:44:52 -0400 [thread overview]
Message-ID: <20201001134452.GD469663@cmpxchg.org> (raw)
In-Reply-To: <20201001002710.748166-4-guro@fb.com>
On Wed, Sep 30, 2020 at 05:27:09PM -0700, Roman Gushchin wrote:
> @@ -448,7 +451,12 @@ static inline void set_page_memcg(struct page *page, struct mem_cgroup *memcg)
> */
> static inline struct obj_cgroup **page_objcgs(struct page *page)
> {
> - return (struct obj_cgroup **)(READ_ONCE(page->memcg_data) & ~0x1UL);
> + unsigned long memcg_data = READ_ONCE(page->memcg_data);
> +
> + VM_BUG_ON_PAGE(memcg_data &&
> + !(memcg_data & MEMCG_DATA_OBJCGS), page);
This fits on a single line.
> + return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
> }
>
> /*
> @@ -463,8 +471,9 @@ static inline struct obj_cgroup **page_objcgs_check(struct page *page)
> {
> unsigned long memcg_data = READ_ONCE(page->memcg_data);
>
> - if (memcg_data && (memcg_data & 0x1UL))
> - return (struct obj_cgroup **)(memcg_data & ~0x1UL);
> + if (memcg_data && (memcg_data & MEMCG_DATA_OBJCGS))
> + return (struct obj_cgroup **)
> + (memcg_data & ~MEMCG_DATA_FLAGS_MASK);
if (!memcg_data || (memcg_data & MEMCG_DATA_OBJCGS))
return NULL;
return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
> @@ -479,7 +488,11 @@ static inline struct obj_cgroup **page_objcgs_check(struct page *page)
> static inline bool set_page_objcgs(struct page *page,
> struct obj_cgroup **objcgs)
> {
> - return !cmpxchg(&page->memcg_data, 0, (unsigned long)objcgs | 0x1UL);
> + unsigned long memcg_data = (unsigned long)objcgs;
> +
> + memcg_data |= MEMCG_DATA_OBJCGS;
> +
> + return !cmpxchg(&page->memcg_data, 0, memcg_data);
return !cmpxchg(&page->memcg_data, 0, memcg_data | MEMCG_DATA_OBJCGS);
next prev parent reply other threads:[~2020-10-01 13:46 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 0:27 [PATCH v4 0/4] mm: allow mapping accounted kernel pages to userspace Roman Gushchin
2020-10-01 0:27 ` [PATCH v4 1/4] mm: memcontrol: use helpers to access page's memcg data Roman Gushchin
2020-10-01 13:46 ` Johannes Weiner
2020-10-01 18:27 ` Roman Gushchin
2020-10-01 18:59 ` Johannes Weiner
2020-10-01 20:51 ` Roman Gushchin
2020-10-02 14:22 ` Johannes Weiner
2020-10-01 0:27 ` [PATCH v4 2/4] mm: memcontrol/slab: use helpers to access slab page's memcg_data Roman Gushchin
2020-10-01 0:27 ` [PATCH v4 3/4] mm: introduce page memcg flags Roman Gushchin
2020-10-01 13:44 ` Johannes Weiner [this message]
2020-10-01 0:27 ` [PATCH v4 4/4] mm: convert page kmemcg type to a page memcg flag Roman Gushchin
2020-10-01 13:48 ` Johannes Weiner
2020-10-01 17:00 ` Michal Koutný
2020-10-01 17:27 ` Johannes Weiner
2020-10-02 10:03 ` Michal Koutný
2020-10-02 13:25 ` Johannes Weiner
2020-10-01 18:30 ` Roman Gushchin
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