From: Johannes Weiner <hannes@cmpxchg.org>
To: Roman Gushchin <guro@fb.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
Shakeel Butt <shakeelb@google.com>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
linux-kernel@vger.kernel.org, kernel-team@fb.com,
Bharata B Rao <bharata@linux.ibm.com>,
Yafang Shao <laoar.shao@gmail.com>
Subject: Re: [PATCH v2 12/28] mm: vmstat: use s32 for vm_node_stat_diff in struct per_cpu_nodestat
Date: Mon, 3 Feb 2020 12:58:18 -0500 [thread overview]
Message-ID: <20200203175818.GF1697@cmpxchg.org> (raw)
In-Reply-To: <20200127173453.2089565-13-guro@fb.com>
On Mon, Jan 27, 2020 at 09:34:37AM -0800, Roman Gushchin wrote:
> Currently s8 type is used for per-cpu caching of per-node statistics.
> It works fine because the overfill threshold can't exceed 125.
>
> But if some counters are in bytes (and the next commit in the series
> will convert slab counters to bytes), it's not gonna work:
> value in bytes can easily exceed s8 without exceeding the threshold
> converted to bytes. So to avoid overfilling per-cpu caches and breaking
> vmstats correctness, let's use s32 instead.
>
> This doesn't affect per-zone statistics. There are no plans to use
> zone-level byte-sized counters, so no reasons to change anything.
Wait, is this still necessary? AFAIU, the node counters will account
full slab pages, including free space, and only the memcg counters
that track actual objects will be in bytes.
Can you please elaborate?
next prev parent reply other threads:[~2020-02-03 18:00 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200127173453.2089565-1-guro@fb.com>
2020-01-27 17:34 ` [PATCH v2 14/28] mm: memcontrol: decouple reference counting from page accounting Roman Gushchin
2020-01-30 2:06 ` [PATCH v2 00/28] The new cgroup slab memory controller Bharata B Rao
2020-01-30 2:41 ` Roman Gushchin
2020-08-12 23:16 ` Pavel Tatashin
2020-08-12 23:18 ` Pavel Tatashin
2020-08-13 0:04 ` Roman Gushchin
2020-08-13 0:31 ` Pavel Tatashin
2020-08-28 16:47 ` Pavel Tatashin
2020-09-01 5:28 ` Bharata B Rao
2020-09-01 12:52 ` Pavel Tatashin
2020-09-02 6:23 ` Bharata B Rao
2020-09-02 12:34 ` Pavel Tatashin
2020-09-02 9:53 ` Vlastimil Babka
2020-09-02 10:39 ` David Hildenbrand
2020-09-02 12:42 ` Pavel Tatashin
2020-09-02 13:50 ` Michal Hocko
2020-09-02 14:20 ` Pavel Tatashin
2020-09-03 18:09 ` David Hildenbrand
2020-09-02 11:26 ` Michal Hocko
2020-09-02 12:51 ` Pavel Tatashin
2020-09-02 13:51 ` Michal Hocko
2020-09-02 11:32 ` Michal Hocko
2020-09-02 12:53 ` Pavel Tatashin
2020-09-02 13:52 ` Michal Hocko
[not found] ` <20200127173453.2089565-28-guro@fb.com>
2020-01-30 2:17 ` [PATCH v2 27/28] tools/cgroup: make slabinfo.py compatible with new slab controller Bharata B Rao
2020-01-30 2:44 ` Roman Gushchin
2020-01-31 22:24 ` Roman Gushchin
2020-02-12 5:21 ` Bharata B Rao
2020-02-12 20:42 ` Roman Gushchin
[not found] ` <20200127173453.2089565-8-guro@fb.com>
2020-02-03 16:05 ` [PATCH v2 07/28] mm: memcg/slab: introduce mem_cgroup_from_obj() Johannes Weiner
[not found] ` <20200127173453.2089565-9-guro@fb.com>
2020-02-03 16:12 ` [PATCH v2 08/28] mm: fork: fix kernel_stack memcg stats for various stack implementations Johannes Weiner
[not found] ` <20200127173453.2089565-10-guro@fb.com>
2020-02-03 16:13 ` [PATCH v2 09/28] mm: memcg/slab: rename __mod_lruvec_slab_state() into __mod_lruvec_obj_state() Johannes Weiner
[not found] ` <20200127173453.2089565-11-guro@fb.com>
2020-02-03 17:39 ` [PATCH v2 10/28] mm: memcg: introduce mod_lruvec_memcg_state() Johannes Weiner
[not found] ` <20200127173453.2089565-12-guro@fb.com>
2020-02-03 17:44 ` [PATCH v2 11/28] mm: slub: implement SLUB version of obj_to_index() Johannes Weiner
[not found] ` <20200127173453.2089565-13-guro@fb.com>
2020-02-03 17:58 ` Johannes Weiner [this message]
2020-02-03 18:25 ` [PATCH v2 12/28] mm: vmstat: use s32 for vm_node_stat_diff in struct per_cpu_nodestat Roman Gushchin
2020-02-03 20:34 ` Johannes Weiner
2020-02-03 22:28 ` Roman Gushchin
2020-02-03 22:39 ` Johannes Weiner
2020-02-04 1:44 ` Roman Gushchin
[not found] ` <20200127173453.2089565-17-guro@fb.com>
2020-02-03 18:27 ` [PATCH v2 16/28] mm: memcg/slab: allocate obj_cgroups for non-root slab pages Johannes Weiner
2020-02-03 18:34 ` Roman Gushchin
2020-02-03 20:46 ` Johannes Weiner
2020-02-03 21:19 ` Roman Gushchin
2020-02-03 22:29 ` Johannes Weiner
[not found] ` <20200127173453.2089565-16-guro@fb.com>
2020-02-03 19:31 ` [PATCH v2 15/28] mm: memcg/slab: obj_cgroup API Johannes Weiner
[not found] ` <20200127173453.2089565-22-guro@fb.com>
2020-02-03 19:50 ` [PATCH v2 21/28] mm: memcg/slab: use a single set of kmem_caches for all memory cgroups Johannes Weiner
2020-02-03 20:58 ` Roman Gushchin
2020-02-03 22:17 ` Johannes Weiner
2020-02-03 22:38 ` Roman Gushchin
2020-02-04 1:15 ` Roman Gushchin
2020-02-04 2:47 ` Johannes Weiner
2020-02-04 4:35 ` Roman Gushchin
2020-02-04 18:41 ` Johannes Weiner
2020-02-05 15:58 ` Roman Gushchin
[not found] ` <20200127173453.2089565-18-guro@fb.com>
2020-02-03 19:53 ` [PATCH v2 17/28] mm: memcg/slab: save obj_cgroup for non-root slab objects Johannes Weiner
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