From: Roman Gushchin <guro@fb.com>
To: Shakeel Butt <shakeelb@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>, Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH v3 3/4] mm: introduce page memcg flags
Date: Wed, 30 Sep 2020 16:44:45 -0700 [thread overview]
Message-ID: <20200930234445.GA2700710@carbon.dhcp.thefacebook.com> (raw)
In-Reply-To: <CALvZod5gMu1OaAspWPQnhCXOmT7U9-cbwBvK83efSYreaNWKNw@mail.gmail.com>
On Wed, Sep 30, 2020 at 04:35:37PM -0700, Shakeel Butt wrote:
> On Tue, Sep 29, 2020 at 4:59 PM Roman Gushchin <guro@fb.com> wrote:
> >
> > The lowest bit in page->memcg_data is used to distinguish between
> > struct memory_cgroup pointer and a pointer to a objcgs array.
> > All checks and modifications of this bit are open-coded.
> >
> > Let's formalize it using page memcg flags, defined in enum
> > page_memcg_data_flags.
> >
> > Additional flags might be added later.
> >
> > Signed-off-by: Roman Gushchin <guro@fb.com>
>
> One nit below:
>
> Reviewed-by: Shakeel Butt <shakeelb@google.com>
Thank you!
>
> > ---
> > include/linux/memcontrol.h | 35 ++++++++++++++++++++++++-----------
> > 1 file changed, 24 insertions(+), 11 deletions(-)
> >
> > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> > index d4d15c04bbaf..35f846c6b89b 100644
> > --- a/include/linux/memcontrol.h
> > +++ b/include/linux/memcontrol.h
> > @@ -343,6 +343,15 @@ struct mem_cgroup {
> >
> > extern struct mem_cgroup *root_mem_cgroup;
> >
> > +enum page_memcg_data_flags {
> > + /* page->memcg_data is a pointer to an objcgs vector */
> > + MEMCG_DATA_OBJCGS,
> > + /* the next bit after the last actual flag */
> > + __NR_MEMCG_DATA_FLAGS,
> > +};
> > +
> > +#define MEMCG_DATA_FLAGS_MASK ((0x1UL << __NR_MEMCG_DATA_FLAGS) - 1)
> > +
>
> Nit:
>
> #define PG_MEMCG_OBJCGS (0x1UL << MEMCG_DATA_OBJCGS)
>
> and use this macro below.
Johannes's pushing on defining flags as bit fields, so I'm sending v4 soon.
Thanks!
next prev parent reply other threads:[~2020-09-30 23:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 23:59 [PATCH v3 0/4] mm: allow mapping accounted kernel pages to userspace Roman Gushchin
2020-09-29 23:59 ` [PATCH v3 1/4] mm: memcontrol: use helpers to access page's memcg data Roman Gushchin
2020-09-30 20:32 ` Johannes Weiner
2020-09-29 23:59 ` [PATCH v3 2/4] mm: memcontrol/slab: use helpers to access slab page's memcg_data Roman Gushchin
2020-09-29 23:59 ` [PATCH v3 3/4] mm: introduce page memcg flags Roman Gushchin
2020-09-30 23:35 ` Shakeel Butt
2020-09-30 23:44 ` Roman Gushchin [this message]
2020-09-29 23:59 ` [PATCH v3 4/4] mm: convert page kmemcg type to a page memcg flag Roman Gushchin
2020-09-30 21:01 ` Johannes Weiner
2020-09-30 21:06 ` Johannes Weiner
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