From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f51.google.com (mail-pb0-f51.google.com [209.85.160.51]) by kanga.kvack.org (Postfix) with ESMTP id F22126B00DA for ; Wed, 6 Nov 2013 09:27:23 -0500 (EST) Received: by mail-pb0-f51.google.com with SMTP id xa7so3226250pbc.10 for ; Wed, 06 Nov 2013 06:27:23 -0800 (PST) Received: from psmtp.com ([74.125.245.140]) by mx.google.com with SMTP id j10si17487779pac.257.2013.11.06.06.27.21 for ; Wed, 06 Nov 2013 06:27:22 -0800 (PST) Date: Wed, 6 Nov 2013 15:31:12 +0200 From: "Kirill A. Shutemov" Subject: lockref: Use bloated_spinlocks to avoid explicit config dependencies Message-ID: <20131106133112.GB22132@shutemov.name> References: <1382442839-7458-1-git-send-email-kirill.shutemov@linux.intel.com> <20131105150145.734a5dd5b5d455800ebfa0d3@linux-foundation.org> <20131105224217.GC20167@shutemov.name> <20131105155619.021f32eba1ca8f15a73ed4c9@linux-foundation.org> <20131105231310.GE20167@shutemov.name> <20131106093131.GU28601@twins.programming.kicks-ass.net> <20131106111845.GG26785@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131106111845.GG26785@twins.programming.kicks-ass.net> Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Andrew Morton , "Kirill A. Shutemov" , Ingo Molnar , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, Linus Torvalds On Wed, Nov 06, 2013 at 12:18:45PM +0100, Peter Zijlstra wrote: > On Wed, Nov 06, 2013 at 10:31:31AM +0100, Peter Zijlstra wrote: > > Subject: mm: Properly separate the bloated ptl from the regular case > > > > Use kernel/bounds.c to convert build-time spinlock_t size into a > > preprocessor symbol and apply that to properly separate the page::ptl > > situation. > > > > Signed-off-by: Peter Zijlstra > > --- > > include/linux/mm.h | 24 +++++++++++++----------- > > include/linux/mm_types.h | 9 +++++---- > > kernel/bounds.c | 2 ++ > > mm/memory.c | 11 +++++------ > > 4 files changed, 25 insertions(+), 21 deletions(-) > > > > diff --git a/kernel/bounds.c b/kernel/bounds.c > > index e8ca97b5c386..5982437eca2c 100644 > > --- a/kernel/bounds.c > > +++ b/kernel/bounds.c > > @@ -11,6 +11,7 @@ > > #include > > #include > > #include > > +#include > > > > void foo(void) > > { > > @@ -21,5 +22,6 @@ void foo(void) > > #ifdef CONFIG_SMP > > DEFINE(NR_CPUS_BITS, ilog2(CONFIG_NR_CPUS)); > > #endif > > + DEFINE(BLOATED_SPINLOCKS, sizeof(spinlock_t) > sizeof(int)); > > /* End of constants */ > > } > > Using that we could also do.. not been near a compiler. > [ Subject adjusted, CC: +Linus ] > --- > Subject: lockref: Use bloated_spinlocks to avoid explicit config dependencies > > Avoid the fragile Kconfig construct guestimating spinlock_t sizes; use a > friendly compile-time test to determine this. > > Not-Signed-off-by: Peter Zijlstra > --- > lib/Kconfig | 3 --- > lib/lockref.c | 2 +- > 2 files changed, 1 insertion(+), 4 deletions(-) > > diff --git a/lib/Kconfig b/lib/Kconfig > index b3c8be0da17f..254af289d1d0 100644 > --- a/lib/Kconfig > +++ b/lib/Kconfig > @@ -54,9 +54,6 @@ config ARCH_USE_CMPXCHG_LOCKREF > config CMPXCHG_LOCKREF > def_bool y if ARCH_USE_CMPXCHG_LOCKREF > depends on SMP > - depends on !GENERIC_LOCKBREAK > - depends on !DEBUG_SPINLOCK > - depends on !DEBUG_LOCK_ALLOC > > config CRC_CCITT > tristate "CRC-CCITT functions" > diff --git a/lib/lockref.c b/lib/lockref.c > index 6f9d434c1521..a158fd86aa1a 100644 > --- a/lib/lockref.c > +++ b/lib/lockref.c > @@ -1,7 +1,7 @@ > #include > #include > > -#ifdef CONFIG_CMPXCHG_LOCKREF > +#if defined(CONFIG_CMPXCHG_LOCKREF) && !BLOATED_SPINLOCKS Having CONFIG_CMPXCHG_LOCKREF=y, but not really using it could be misleading. Should we get rid of CONFIG_CMPXCHG_LOCKREF completely and have here: #if defined(CONFIG_ARCH_USE_CMPXCHG_LOCKREF) && \ defined(CONFIG_SMP) && !BLOATED_SPINLOCKS ? -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org