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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201001134452.GD469663@cmpxchg.org \
--to=hannes@cmpxchg.org \
--cc=akpm@linux-foundation.org \
--cc=guro@fb.com \
--cc=kernel-team@fb.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=shakeelb@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.