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SubjectRe: [PATCH mmotm] Fix NUMA accounting in numastat.txt
On Tue, 1 Sep 2009 16:24:19 +0900
Minchan Kim <minchan.kim@gmail.com> wrote:

> Hi, Kame.
>
> On Tue, 1 Sep 2009 16:17:21 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>
> > On Tue, 1 Sep 2009 13:53:21 +0900
> > Minchan Kim <minchan.kim@gmail.com> wrote:
> >
> > >
> > > In Documentation/numastat.txt, it confused me.
> > > For example, there are nodes [0,1] in system.
> > >
> > > barrios:~$ cat /proc/zoneinfo | egrep 'numa|zone'
> > > Node 0, zone DMA
> > > numa_hit 33226
> > > numa_miss 1739
> > > numa_foreign 27978
> > > ..
> > > ..
> > > Node 1, zone DMA
> > > numa_hit 307
> > > numa_miss 46900
> > > numa_foreign 0
> > >
> > > 1) In node 0, NUMA_MISS means it wanted to allocate page
> > > in node 1 but ended up with page in node 0
> > >
> > > 2) In node 0, NUMA_FOREIGN means it wanted to allocate page
> > > in node 0 but ended up with page from Node 1.
> > >
> > > But now, numastat explains it oppositely about (MISS, FOREIGN).
> > > Let's fix up with viewpoint of zone.
> > >
> >
> > I'm confused....documentation is really bad ?
> > Implementation isn't ?
>
> At that time, I though of it.
> But I knew code is right since zone_stat_item said follwing as.
> NUMA_MISS is rather unclear but NUMA_FOREIGN is clear, I think.
>
> NUMA_MISS, /* allocated in non intended node */
> NUMA_FOREIGN, /* was intended here, hit elsewhere */
>
Ah, ok, it comments are correct your patch makes sense.

> Also I am worry about legacy tools related to NUMA but I don't know it.
> Code change will break them.
Ah, hmm. maybe.

Thanks. Add Christoph to CC:, maybe he can Ack.

Thanks,
-Kame




> > Hmm, this function ?
> > ==
> > void zone_statistics(struct zone *preferred_zone, struct zone *z)
> > {
> > if (z->zone_pgdat == preferred_zone->zone_pgdat) {
> > __inc_zone_state(z, NUMA_HIT);
> > } else {
> > __inc_zone_state(z, NUMA_MISS);
> > __inc_zone_state(preferred_zone, NUMA_FOREIGN);
> > }
> > if (z->node == numa_node_id())
> > __inc_zone_state(z, NUMA_LOCAL);
> > else
> > __inc_zone_state(z, NUMA_OTHER);
> > }
> > ==
> >
> >
> > > Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
> > > ---
> > > Documentation/numastat.txt | 8 ++++----
> > > 1 files changed, 4 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/Documentation/numastat.txt b/Documentation/numastat.txt
> > > index 80133ac..9fcc9a6 100644
> > > --- a/Documentation/numastat.txt
> > > +++ b/Documentation/numastat.txt
> > > @@ -7,10 +7,10 @@ All units are pages. Hugepages have separate counters.
> > >
> > > numa_hit A process wanted to allocate memory from this node,
> > > and succeeded.
> > > -numa_miss A process wanted to allocate memory from this node,
> > > - but ended up with memory from another.
> > > -numa_foreign A process wanted to allocate on another node,
> > > - but ended up with memory from this one.
> > > +numa_miss A process wanted to allocate memory from another node,
> > > + but ended up with memory from this node.
> > > +numa_foreign A process wanted to allocate on this node,
> > > + but ended up with memory from another one.
> > > local_node A process ran on this node and got memory from it.
> > > other_node A process ran on this node and got memory from another node.
> > > interleave_hit Interleaving wanted to allocate from this node
> > > --
> > > 1.5.4.3
> > >
> > >
> > >
> > > --
> > > Kind regards,
> > > Minchan Kim
> > >
> > > --
> > > To unsubscribe, send a message with 'unsubscribe linux-mm' in
> > > the body to majordomo@kvack.org. For more info on Linux MM,
> > > see: http://www.linux-mm.org/ .
> > > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
> > >
> >
>
>
> --
> Kind regards,
> Minchan Kim
>



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