From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756607AbcK2LO7 (ORCPT ); Tue, 29 Nov 2016 06:14:59 -0500 Received: from mail-wj0-f194.google.com ([209.85.210.194]:34301 "EHLO mail-wj0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755534AbcK2LOx (ORCPT ); Tue, 29 Nov 2016 06:14:53 -0500 MIME-Version: 1.0 In-Reply-To: <1475004808-91920-1-git-send-email-babu.moger@oracle.com> References: <1475004808-91920-1-git-send-email-babu.moger@oracle.com> From: Geert Uytterhoeven Date: Tue, 29 Nov 2016 12:14:48 +0100 X-Google-Sender-Auth: 7q1kBEPPAvjomE6UoQOcQMQGVOo Message-ID: Subject: Re: [PATCH v3 0/2] Ajust lockdep static allocations for sparc To: Babu Moger Cc: Peter Zijlstra , Ingo Molnar , Andrew Morton , Kees Cook , Dan Williams , Andrey Ryabinin , Tejun Heo , Sam Ravnborg , "linux-kernel@vger.kernel.org" , sparclinux , Linux-Renesas Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CC linux-renesas-soc On Tue, Sep 27, 2016 at 9:33 PM, Babu Moger 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@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