Hi Oliver, Yogesh,
On Wed, Apr 14, 2021 at 8:08 PM <glittao@xxxxxxxxx> wrote:
> From: Oliver Glitta <glittao@xxxxxxxxx>
>
> 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@xxxxxxxxx>
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@xxxxxxxxxxxxxx
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
