From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Roman Gushchin <guro@fb.com>
Cc: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
netdev@vger.kernel.org, andrii@kernel.org,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH bpf-next v7 32/34] bpf: eliminate rlimit-based memory accounting infra for bpf maps
Date: Fri, 20 Nov 2020 18:52:27 -0800 [thread overview]
Message-ID: <20201121025227.dypweojhaz7elwb3@ast-mbp> (raw)
In-Reply-To: <20201119173754.4125257-33-guro@fb.com>
On Thu, Nov 19, 2020 at 09:37:52AM -0800, Roman Gushchin wrote:
> static void bpf_map_put_uref(struct bpf_map *map)
> @@ -619,7 +562,7 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
> "value_size:\t%u\n"
> "max_entries:\t%u\n"
> "map_flags:\t%#x\n"
> - "memlock:\t%llu\n"
> + "memlock:\t%llu\n" /* deprecated */
> "map_id:\t%u\n"
> "frozen:\t%u\n",
> map->map_type,
> @@ -627,7 +570,7 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
> map->value_size,
> map->max_entries,
> map->map_flags,
> - map->memory.pages * 1ULL << PAGE_SHIFT,
> + 0LLU,
The set looks great to me overall, but above change is problematic.
There are tools out there that read this value.
Returning zero might cause oncall alarms to trigger.
I think we can be more accurate here.
Instead of zero the kernel can return
round_up(max_entries * round_up(key_size + value_size, 8), PAGE_SIZE)
It's not the same as before, but at least the numbers won't suddenly
go to zero and comparison between maps is still relevant.
Of course we can introduce a page size calculating callback per map type,
but imo that would be overkill. These monitoring tools don't care about
precise number, but rather about relative value and growth from one
version of the application to another.
If Daniel doesn't find other issues this can be fixed in the follow up.
next prev parent reply other threads:[~2020-11-21 2:52 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-19 17:37 [PATCH bpf-next v7 00/34] bpf: switch to memcg-based memory accounting Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 01/34] mm: memcontrol: use helpers to read page's memcg data Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 02/34] mm: memcontrol/slab: use helpers to access slab page's memcg_data Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 03/34] mm: introduce page memcg flags Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 04/34] mm: convert page kmemcg type to a page memcg flag Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 05/34] bpf: memcg-based memory accounting for bpf progs Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 06/34] bpf: prepare for memcg-based memory accounting for bpf maps Roman Gushchin
2020-11-20 1:05 ` Song Liu
2020-11-19 17:37 ` [PATCH bpf-next v7 07/34] bpf: " Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 08/34] bpf: refine memcg-based memory accounting for arraymap maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 09/34] bpf: refine memcg-based memory accounting for cpumap maps Roman Gushchin
2020-11-20 1:33 ` Song Liu
2020-11-19 17:37 ` [PATCH bpf-next v7 10/34] bpf: memcg-based memory accounting for cgroup storage maps Roman Gushchin
2020-11-20 1:37 ` Song Liu
2020-11-19 17:37 ` [PATCH bpf-next v7 11/34] bpf: refine memcg-based memory accounting for devmap maps Roman Gushchin
2020-11-20 1:38 ` Song Liu
2020-11-19 17:37 ` [PATCH bpf-next v7 12/34] bpf: refine memcg-based memory accounting for hashtab maps Roman Gushchin
2020-11-20 1:39 ` Song Liu
2020-11-19 17:37 ` [PATCH bpf-next v7 13/34] bpf: memcg-based memory accounting for lpm_trie maps Roman Gushchin
2020-11-20 1:39 ` Song Liu
2020-11-19 17:37 ` [PATCH bpf-next v7 14/34] bpf: memcg-based memory accounting for bpf ringbuffer Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 15/34] bpf: memcg-based memory accounting for bpf local storage maps Roman Gushchin
2020-11-20 1:44 ` Song Liu
2020-11-19 17:37 ` [PATCH bpf-next v7 16/34] bpf: refine memcg-based memory accounting for sockmap and sockhash maps Roman Gushchin
2020-11-20 1:45 ` Song Liu
2020-11-19 17:37 ` [PATCH bpf-next v7 17/34] bpf: refine memcg-based memory accounting for xskmap maps Roman Gushchin
2020-11-20 1:45 ` Song Liu
2020-11-19 17:37 ` [PATCH bpf-next v7 18/34] bpf: eliminate rlimit-based memory accounting for arraymap maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 19/34] bpf: eliminate rlimit-based memory accounting for bpf_struct_ops maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 20/34] bpf: eliminate rlimit-based memory accounting for cpumap maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 21/34] bpf: eliminate rlimit-based memory accounting for cgroup storage maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 22/34] bpf: eliminate rlimit-based memory accounting for devmap maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 23/34] bpf: eliminate rlimit-based memory accounting for hashtab maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 24/34] bpf: eliminate rlimit-based memory accounting for lpm_trie maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 25/34] bpf: eliminate rlimit-based memory accounting for queue_stack_maps maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 26/34] bpf: eliminate rlimit-based memory accounting for reuseport_array maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 27/34] bpf: eliminate rlimit-based memory accounting for bpf ringbuffer Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 28/34] bpf: eliminate rlimit-based memory accounting for sockmap and sockhash maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 29/34] bpf: eliminate rlimit-based memory accounting for stackmap maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 30/34] bpf: eliminate rlimit-based memory accounting for xskmap maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 31/34] bpf: eliminate rlimit-based memory accounting for bpf local storage maps Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 32/34] bpf: eliminate rlimit-based memory accounting infra for bpf maps Roman Gushchin
2020-11-21 2:52 ` Alexei Starovoitov [this message]
2020-11-21 2:59 ` Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 33/34] bpf: eliminate rlimit-based memory accounting for bpf progs Roman Gushchin
2020-11-19 17:37 ` [PATCH bpf-next v7 34/34] bpf: samples: do not touch RLIMIT_MEMLOCK Roman Gushchin
2020-11-23 13:30 ` [PATCH bpf-next v7 00/34] bpf: switch to memcg-based memory accounting Daniel Borkmann
2020-11-24 0:05 ` Roman Gushchin
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