From: Geert Uytterhoeven <geert@linux-m68k.org>
To: glittao@gmail.com, Yogesh Lal <ylal@codeaurora.org>
Cc: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>
Subject: Re: [PATCH] mm/slub: use stackdepot to save stack trace in objects
Date: Tue, 13 Jul 2021 14:03:39 +0200 [thread overview]
Message-ID: <CAMuHMdW=eoVzM1Re5FVoEN87nKfiLmM2+Ah7eNu2KXEhCvbZyA@mail.gmail.com> (raw)
In-Reply-To: <20210414163434.4376-1-glittao@gmail.com>
Hi Oliver, Yogesh,
On Wed, Apr 14, 2021 at 8:08 PM <glittao@gmail.com> wrote:
> From: Oliver Glitta <glittao@gmail.com>
>
> Many stack traces are similar so there are many similar arrays.
> Stackdepot saves each unique stack only once.
>
> Replace field addrs in struct track with depot_stack_handle_t handle.
> Use stackdepot to save stack trace.
>
> The benefits are smaller memory overhead and possibility to aggregate
> per-cache statistics in the future using the stackdepot handle
> instead of matching stacks manually.
>
> Signed-off-by: Oliver Glitta <glittao@gmail.com>
Thanks for your patch, which is now commit 788691464c294553 ("mm/slub:
use stackdepot to save stack trace in objects") in v5.14-rc1.
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1891,6 +1891,7 @@ config SLUB_DEBUG
> default y
> bool "Enable SLUB debugging support" if EXPERT
> depends on SLUB && SYSFS
> + select STACKDEPOT if STACKTRACE_SUPPORT
> help
> SLUB has extensive debug support features. Disabling these can
> result in significant savings in code size. This also disables
This change increases memory consumption by 4 MiB (or more, see below).
Looking at lib/Kconfig:
| config STACK_HASH_ORDER
| int "stack depot hash size (12 => 4KB, 20 => 1024KB)"
The sizes reported here are not correct, as the actual memory consumption
is not STACK_HAS_ORDER bytes, but STACK_HAS_ORDER pointers.
Hence they're off by a factor of 4 or 8.
| range 12 20
| default 20
Does this really have to default to the maximum value?
| depends on STACKDEPOT
| help
| Select the hash size as a power of 2 for the stackdepot hash table.
| Choose a lower value to reduce the memory impact.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
prev parent reply other threads:[~2021-07-13 12:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 16:34 [PATCH] mm/slub: use stackdepot to save stack trace in objects glittao
2021-04-20 16:58 ` Vlastimil Babka
2021-04-26 1:10 ` David Rientjes
2021-05-10 4:46 ` Andrew Morton
2021-05-12 14:33 ` Vlastimil Babka
2021-05-13 0:07 ` Andrew Morton
2021-05-16 19:51 ` [PATCH] mm/slub: use stackdepot to save stack trace in objects-fix Vlastimil Babka
2021-07-02 15:37 ` [PATCH] mm/slub: use stackdepot to save stack trace in objects Guenter Roeck
2021-07-02 16:01 ` Vlastimil Babka
2021-07-13 12:03 ` Geert Uytterhoeven [this message]
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