From: Roman Gushchin <guro@fb.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>,
vinayak menon <vinayakm.list@gmail.com>, <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<kernel-team@fb.com>, Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCH 1/3] mm: introduce NR_INDIRECTLY_RECLAIMABLE_BYTES
Date: Wed, 25 Apr 2018 18:23:04 +0100 [thread overview]
Message-ID: <20180425172258.GA8052@castle> (raw)
In-Reply-To: <7fc2986e-b867-eb32-9124-d10ef6c1a3a3@suse.cz>
On Wed, Apr 25, 2018 at 07:02:42PM +0200, Vlastimil Babka wrote:
> On 04/25/2018 06:48 PM, Roman Gushchin wrote:
> > On Wed, Apr 25, 2018 at 05:47:26PM +0200, Vlastimil Babka wrote:
> >> On 04/25/2018 02:52 PM, Roman Gushchin wrote:
> >>> On Wed, Apr 25, 2018 at 09:19:29AM +0530, Vijayanand Jitta wrote:
> >>>>>>>> Idk, I don't like the idea of adding a counter outside of the vm counters
> >>>>>>>> infrastructure, and I definitely wouldn't touch the exposed
> >>>>>>>> nr_slab_reclaimable and nr_slab_unreclaimable fields.
> >>>>>>>
> >>>>>>> We would be just making the reported values more precise wrt reality.
> >>>>>>
> >>>>>> It depends on if we believe that only slab memory can be reclaimable
> >>>>>> or not. If yes, this is true, otherwise not.
> >>>>>>
> >>>>>> My guess is that some drivers (e.g. networking) might have buffers,
> >>>>>> which are reclaimable under mempressure, and are allocated using
> >>>>>> the page allocator. But I have to look closer...
> >>>>>>
> >>>>>
> >>>>> One such case I have encountered is that of the ION page pool. The page pool
> >>>>> registers a shrinker. When not in any memory pressure page pool can go high
> >>>>> and thus cause an mmap to fail when OVERCOMMIT_GUESS is set. I can send
> >>>>> a patch to account ION page pool pages in NR_INDIRECTLY_RECLAIMABLE_BYTES.
> >>
> >> FYI, we have discussed this at LSF/MM and agreed to try the kmalloc
> >> reclaimable caches idea. The existing counter could then remain for page
> >> allocator users such as ION. It's a bit weird to have it in bytes and
> >> not pages then, IMHO. What if we hid it from /proc/vmstat now so it
> >> doesn't become ABI, and later convert it to page granularity and expose
> >> it under a name such as "nr_other_reclaimable" ?
> >
> > I've nothing against hiding it from /proc/vmstat, as long as we keep
> > the counter in place and the main issue resolved.
>
> Sure.
>
> > Maybe it's better to add nr_reclaimable = nr_slab_reclaimable + nr_other_reclaimable,
> > which will have a simpler meaning that nr_other_reclaimable (what is other?).
>
> "other" can be changed, sure. nr_reclaimable is possible if we change
> slab to adjust that counter as well - vmstat code doesn't support
> arbitrary calculations when printing.
Sure, but even just hiding a value isn't that easy now.
So we have to touch the vmstat printing code anyway.
Thanks!
next prev parent reply other threads:[~2018-04-25 17:23 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-05 13:37 [PATCH 0/3] indirectly reclaimable memory Roman Gushchin
2018-03-05 13:37 ` [PATCH 1/3] mm: introduce NR_INDIRECTLY_RECLAIMABLE_BYTES Roman Gushchin
2018-04-11 13:16 ` Vlastimil Babka
2018-04-11 13:56 ` Roman Gushchin
2018-04-12 6:52 ` Vlastimil Babka
2018-04-12 11:52 ` Michal Hocko
2018-04-12 14:38 ` Roman Gushchin
2018-04-12 14:46 ` Michal Hocko
2018-04-12 14:57 ` Roman Gushchin
2018-04-13 6:59 ` Michal Hocko
2018-04-13 12:13 ` vinayak menon
2018-04-25 3:49 ` Vijayanand Jitta
2018-04-25 12:52 ` Roman Gushchin
2018-04-25 15:47 ` Vlastimil Babka
2018-04-25 16:48 ` Roman Gushchin
2018-04-25 17:02 ` Vlastimil Babka
2018-04-25 17:23 ` Roman Gushchin [this message]
2018-04-25 15:55 ` Matthew Wilcox
2018-04-25 16:59 ` Vlastimil Babka
2018-03-05 13:37 ` [PATCH 2/3] mm: add indirectly reclaimable memory to MemAvailable Roman Gushchin
2018-03-05 13:47 ` Roman Gushchin
2018-03-05 13:37 ` [PATCH 2/3] mm: treat indirectly reclaimable memory as available in MemAvailable Roman Gushchin
2018-03-05 13:37 ` [PATCH 3/3] dcache: account external names as indirectly reclaimable memory Roman Gushchin
2018-03-12 21:17 ` Al Viro
2018-03-12 22:36 ` Roman Gushchin
2018-03-13 0:45 ` Al Viro
2018-04-05 22:11 ` Andrew Morton
2018-04-06 10:32 ` Roman Gushchin
2018-04-13 13:35 ` Minchan Kim
2018-04-13 13:59 ` Michal Hocko
2018-04-13 14:20 ` Vlastimil Babka
2018-04-13 14:28 ` Michal Hocko
2018-04-13 14:37 ` Johannes Weiner
2018-04-16 11:41 ` Michal Hocko
2018-04-16 12:06 ` Vlastimil Babka
2018-04-16 12:27 ` Michal Hocko
2018-04-16 19:57 ` Vlastimil Babka
2018-04-17 6:44 ` Michal Hocko
2018-04-16 13:09 ` Matthew Wilcox
2018-04-17 11:24 ` Roman Gushchin
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