CC linux-renesas-soc
On Tue, Sep 27, 2016 at 9:33 PM, Babu Moger <babu.moger@xxxxxxxxxx> wrote:
> These patches limit the static allocations for lockdep data structures
> used for debugging locking correctness. For sparc, all the kernel's code,
> data, and bss, must have locked translations in the TLB so that we don't
> get TLB misses on kernel code and data. Current sparc chips have 8 TLB
> entries available that may be locked down, and with a 4mb page size,
> this gives a maximum of 32MB. With PROVE_LOCKING we could go over this
> limit and cause system boot-up problems. These patches limit the static
> allocations so that everything fits in current required size limit.
>
> patch 1 : Adds new config parameter CONFIG_PROVE_LOCKING_SMALL
> Patch 2 : Adjusts the sizes based on the new config parameter
Cool, this is also useful on other platforms!
E.g. on r8a7791/koelsch, I cannot boot an shmobile_defconfig plus
CONFIG_PROVE_LOCKING kernel.
Forcing CONFIG_PROVE_LOCKING_SMALL=y in Kconfig fixes that.
Should it become a user-selectable symbol?
> v2-> v3:
> Some more comments from Sam Ravnborg and Peter Zijlstra.
> Defined PROVE_LOCKING_SMALL as invisible and moved the selection to
> arch/sparc/Kconfig.
>
> v1-> v2:
> As suggested by Peter Zijlstra, keeping the default as is.
> Introduced new config variable CONFIG_PROVE_LOCKING_SMALL
> to handle sparc specific case.
>
> v0:
> Initial revision.
>
> Babu Moger (2):
> config: Adding the new config parameter CONFIG_PROVE_LOCKING_SMALL
> for sparc
> lockdep: Limit static allocations if PROVE_LOCKING_SMALL is defined
>
> arch/sparc/Kconfig | 1 +
> kernel/locking/lockdep_internals.h | 20 +++++++++++++++++---
> lib/Kconfig.debug | 3 +++
> 3 files changed, 21 insertions(+), 3 deletions(-)
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
