From: Muchun Song <songmuchun@bytedance.com>
To: Roman Gushchin <guro@fb.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
rafael@kernel.org, Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Hugh Dickins <hughd@google.com>, Will Deacon <will@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
esyr@redhat.com, peterx@redhat.com, krisman@collabora.com,
Suren Baghdasaryan <surenb@google.com>,
avagin@openvz.org, Marco Elver <elver@google.com>,
Randy Dunlap <rdunlap@infradead.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Cgroups <cgroups@vger.kernel.org>
Subject: Re: [External] Re: [RESEND PATCH v2 09/12] mm: memcontrol: convert vmstat slab counters to bytes
Date: Tue, 8 Dec 2020 10:44:18 +0800 [thread overview]
Message-ID: <CAMZfGtWFrauMfoP6KisvaocY3Y86VXw6YjnV5hiZVWZA6tn-cw@mail.gmail.com> (raw)
In-Reply-To: <20201207194622.GA2238414@carbon.dhcp.thefacebook.com>
On Tue, Dec 8, 2020 at 3:46 AM Roman Gushchin <guro@fb.com> wrote:
>
> On Sun, Dec 06, 2020 at 06:14:48PM +0800, Muchun Song wrote:
> > the global and per-node counters are stored in pages, however memcg
> > and lruvec counters are stored in bytes. This scheme looks weird.
> > So convert all vmstat slab counters to bytes.
>
> There is a reason for this weird scheme:
> percpu caches (see struct per_cpu_nodestat) are s8, so counting in bytes
> will lead to overfills. Switching to s32 can lead to an increase in
> the cache thrashing, especially on small machines.
Thanks Roman. I see now.
>
> >
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > ---
> > include/linux/vmstat.h | 17 ++++++++++-------
> > mm/vmstat.c | 21 ++++++++++-----------
> > 2 files changed, 20 insertions(+), 18 deletions(-)
> >
> > diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
> > index 322dcbfcc933..fd1a3d5d4926 100644
> > --- a/include/linux/vmstat.h
> > +++ b/include/linux/vmstat.h
> > @@ -197,18 +197,26 @@ static inline
> > unsigned long global_node_page_state_pages(enum node_stat_item item)
> > {
> > long x = atomic_long_read(&vm_node_stat[item]);
> > +
> > #ifdef CONFIG_SMP
> > if (x < 0)
> > x = 0;
> > #endif
> > + if (vmstat_item_in_bytes(item))
> > + x >>= PAGE_SHIFT;
> > return x;
> > }
> >
> > static inline unsigned long global_node_page_state(enum node_stat_item item)
> > {
> > - VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
> > + long x = atomic_long_read(&vm_node_stat[item]);
> >
> > - return global_node_page_state_pages(item);
> > + VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
> > +#ifdef CONFIG_SMP
> > + if (x < 0)
> > + x = 0;
> > +#endif
> > + return x;
> > }
> >
> > static inline unsigned long zone_page_state(struct zone *zone,
> > @@ -312,11 +320,6 @@ static inline void __mod_zone_page_state(struct zone *zone,
> > static inline void __mod_node_page_state(struct pglist_data *pgdat,
> > enum node_stat_item item, int delta)
> > {
> > - if (vmstat_item_in_bytes(item)) {
> > - VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
> > - delta >>= PAGE_SHIFT;
> > - }
> > -
> > node_page_state_add(delta, pgdat, item);
> > }
> >
> > diff --git a/mm/vmstat.c b/mm/vmstat.c
> > index 8d77ee426e22..7fb0c7cb9516 100644
> > --- a/mm/vmstat.c
> > +++ b/mm/vmstat.c
> > @@ -345,11 +345,6 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
> > long x;
> > long t;
> >
> > - if (vmstat_item_in_bytes(item)) {
> > - VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
> > - delta >>= PAGE_SHIFT;
> > - }
> > -
> > x = delta + __this_cpu_read(*p);
> >
> > t = __this_cpu_read(pcp->stat_threshold);
> > @@ -554,11 +549,6 @@ static inline void mod_node_state(struct pglist_data *pgdat,
> > s8 __percpu *p = pcp->vm_node_stat_diff + item;
> > long o, n, t, z;
> >
> > - if (vmstat_item_in_bytes(item)) {
> > - VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
> > - delta >>= PAGE_SHIFT;
> > - }
> > -
> > do {
> > z = 0; /* overflow to node counters */
> >
> > @@ -1012,19 +1002,28 @@ unsigned long node_page_state_pages(struct pglist_data *pgdat,
> > enum node_stat_item item)
> > {
> > long x = atomic_long_read(&pgdat->vm_stat[item]);
> > +
> > #ifdef CONFIG_SMP
> > if (x < 0)
> > x = 0;
> > #endif
> > + if (vmstat_item_in_bytes(item))
> > + x >>= PAGE_SHIFT;
> > return x;
> > }
> >
> > unsigned long node_page_state(struct pglist_data *pgdat,
> > enum node_stat_item item)
> > {
> > + long x = atomic_long_read(&pgdat->vm_stat[item]);
> > +
> > VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
> >
> > - return node_page_state_pages(pgdat, item);
> > +#ifdef CONFIG_SMP
> > + if (x < 0)
> > + x = 0;
> > +#endif
> > + return x;
> > }
> > #endif
> >
> > --
> > 2.11.0
> >
--
Yours,
Muchun
next prev parent reply other threads:[~2020-12-08 2:44 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-06 10:14 [RESEND PATCH v2 00/12] Convert all vmstat counters to pages or bytes Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 01/12] mm: memcontrol: fix NR_ANON_THPS account Muchun Song
2020-12-07 12:52 ` Michal Hocko
2020-12-10 16:00 ` Johannes Weiner
2020-12-10 16:02 ` Johannes Weiner
2020-12-10 16:04 ` Johannes Weiner
2020-12-10 16:56 ` [External] " Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 02/12] mm: memcontrol: convert NR_ANON_THPS account to pages Muchun Song
2020-12-10 16:10 ` Johannes Weiner
2020-12-10 17:05 ` [External] " Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 03/12] mm: memcontrol: convert NR_FILE_THPS " Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 04/12] mm: memcontrol: convert NR_SHMEM_THPS " Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 05/12] mm: memcontrol: convert NR_SHMEM_PMDMAPPED " Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 06/12] mm: memcontrol: convert NR_FILE_PMDMAPPED " Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 07/12] mm: memcontrol: convert kernel stack account to bytes Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 08/12] mm: memcontrol: convert NR_KERNEL_SCS_KB " Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 09/12] mm: memcontrol: convert vmstat slab counters " Muchun Song
2020-12-07 19:46 ` Roman Gushchin
2020-12-07 20:01 ` Roman Gushchin
2020-12-08 2:44 ` Muchun Song [this message]
2020-12-06 10:14 ` [RESEND PATCH v2 10/12] mm: memcontrol: scale stat_threshold for byted-sized vmstat Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 11/12] mm: memcontrol: make the slab calculation consistent Muchun Song
2020-12-06 10:14 ` [RESEND PATCH v2 12/12] mm: memcontrol: remove {global_}node_page_state_pages Muchun Song
2020-12-07 13:00 ` [RESEND PATCH v2 00/12] Convert all vmstat counters to pages or bytes Michal Hocko
2020-12-07 14:52 ` [External] " Muchun Song
2020-12-07 15:02 ` Michal Hocko
2020-12-07 18:51 ` Randy Dunlap
2020-12-08 2:29 ` Muchun Song
2020-12-07 19:51 ` Roman Gushchin
2020-12-07 20:33 ` Hugh Dickins
2020-12-08 2:42 ` Muchun Song
2020-12-08 2:40 ` Muchun Song
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