From: Russell King - ARM Linux <linux@arm.linux.org.uk> To: Tony Lindgren <tony@atomide.com> Cc: linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, bryan.wu@canonical.com Subject: Re: [PATCH 2/4] ARM: Allow optional UP processor functions for SMP kernels Date: Tue, 17 Aug 2010 12:08:57 +0100 [thread overview] Message-ID: <20100817110857.GB20325@n2100.arm.linux.org.uk> (raw) In-Reply-To: <20100817105325.19061.93324.stgit@baageli.muru.com> On Tue, Aug 17, 2010 at 01:53:25PM +0300, Tony Lindgren wrote: > diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h > index e621530..1c2f587 100644 > --- a/arch/arm/include/asm/smp_plat.h > +++ b/arch/arm/include/asm/smp_plat.h > @@ -18,4 +18,13 @@ static inline int cache_ops_need_broadcast(void) > return ((read_cpuid_ext(CPUID_EXT_MMFR3) >> 12) & 0xf) < 1; > } > > +#ifdef CONFIG_SMP_ON_UP > +extern int smp_on_up(void); > +#else > +static inline int smp_on_up(void) > +{ > + return 0; > +} > +#endif > + > #endif > diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c > index d5231ae..5f3606c 100644 > --- a/arch/arm/kernel/setup.c > +++ b/arch/arm/kernel/setup.c > @@ -289,6 +289,50 @@ static void __init feat_v6_fixup(void) > elf_hwcap &= ~HWCAP_TLS; > } > > +#ifdef CONFIG_SMP_ON_UP > + > +static int _smp_on_up; > + > +int smp_on_up(void) > +{ > + return _smp_on_up; > +} This kind of function to access one bit of data is really silly and expensive. If you want to do something like this to hide the data itself, then instead do this in the header file: static inline int smp_on_up(void) { #ifdef CONFIG_SMP_ON_UP extern int _smp_on_up; return _smp_on_up; #else return 0; #endif } rather than making the compiler unable to optimize this call by spilling at least 5 registers each time. > + if (list->proc_up) > + processor = *list->proc_up; > + > + if (list->tlb_up) > + cpu_tlb = *list->tlb_up; > + > + if (list->cache_up) > + cpu_cache = *list->cache_up; I don't think this is a good approach at all - most of the assembly is identical and I'm sure there's a much better approach to fixing these things up.
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From: linux@arm.linux.org.uk (Russell King - ARM Linux) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/4] ARM: Allow optional UP processor functions for SMP kernels Date: Tue, 17 Aug 2010 12:08:57 +0100 [thread overview] Message-ID: <20100817110857.GB20325@n2100.arm.linux.org.uk> (raw) In-Reply-To: <20100817105325.19061.93324.stgit@baageli.muru.com> On Tue, Aug 17, 2010 at 01:53:25PM +0300, Tony Lindgren wrote: > diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h > index e621530..1c2f587 100644 > --- a/arch/arm/include/asm/smp_plat.h > +++ b/arch/arm/include/asm/smp_plat.h > @@ -18,4 +18,13 @@ static inline int cache_ops_need_broadcast(void) > return ((read_cpuid_ext(CPUID_EXT_MMFR3) >> 12) & 0xf) < 1; > } > > +#ifdef CONFIG_SMP_ON_UP > +extern int smp_on_up(void); > +#else > +static inline int smp_on_up(void) > +{ > + return 0; > +} > +#endif > + > #endif > diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c > index d5231ae..5f3606c 100644 > --- a/arch/arm/kernel/setup.c > +++ b/arch/arm/kernel/setup.c > @@ -289,6 +289,50 @@ static void __init feat_v6_fixup(void) > elf_hwcap &= ~HWCAP_TLS; > } > > +#ifdef CONFIG_SMP_ON_UP > + > +static int _smp_on_up; > + > +int smp_on_up(void) > +{ > + return _smp_on_up; > +} This kind of function to access one bit of data is really silly and expensive. If you want to do something like this to hide the data itself, then instead do this in the header file: static inline int smp_on_up(void) { #ifdef CONFIG_SMP_ON_UP extern int _smp_on_up; return _smp_on_up; #else return 0; #endif } rather than making the compiler unable to optimize this call by spilling at least 5 registers each time. > + if (list->proc_up) > + processor = *list->proc_up; > + > + if (list->tlb_up) > + cpu_tlb = *list->tlb_up; > + > + if (list->cache_up) > + cpu_cache = *list->cache_up; I don't think this is a good approach at all - most of the assembly is identical and I'm sure there's a much better approach to fixing these things up.
next prev parent reply other threads:[~2010-08-17 11:09 UTC|newest] Thread overview: 230+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-08-17 10:53 [PATCH 0/4] Hacks to allow booting ARM SMP kernel on UP ARMv7 Tony Lindgren 2010-08-17 10:53 ` Tony Lindgren 2010-08-17 10:53 ` [PATCH 1/4] ARM: Add SMP_ON_UP Kconfig option for booting SMP kernel on UP Tony Lindgren 2010-08-17 10:53 ` Tony Lindgren 2010-08-17 10:53 ` [PATCH 2/4] ARM: Allow optional UP processor functions for SMP kernels Tony Lindgren 2010-08-17 10:53 ` Tony Lindgren 2010-08-17 11:08 ` Russell King - ARM Linux [this message] 2010-08-17 11:08 ` Russell King - ARM Linux 2010-08-17 11:20 ` Tony Lindgren 2010-08-17 11:20 ` Tony Lindgren 2010-08-17 10:53 ` [PATCH 3/4] ARM: Set separate proc-v7 functions for SMP Tony Lindgren 2010-08-17 10:53 ` Tony Lindgren 2010-08-17 10:53 ` [PATCH 4/4] omap: Fix SMP on UP interrupt handling for multi-omap Tony Lindgren 2010-08-17 10:53 ` Tony Lindgren 2010-08-17 11:07 ` srinidhi 2010-08-17 11:07 ` srinidhi 2010-08-17 11:30 ` Tony Lindgren 2010-08-17 11:30 ` Tony Lindgren 2010-08-17 12:14 ` srinidhi 2010-08-17 12:14 ` srinidhi 2010-08-17 14:14 ` Tony Lindgren 2010-08-17 14:14 ` Tony Lindgren 2010-08-17 15:07 ` Shilimkar, Santosh 2010-08-17 15:07 ` Shilimkar, Santosh 2010-09-02 16:27 ` Tony Lindgren 2010-09-02 16:27 ` Tony Lindgren 2010-08-17 13:52 ` [PATCH 0/4] Hacks to allow booting ARM SMP kernel on UP ARMv7 Russell King - ARM Linux 2010-08-17 13:52 ` Russell King - ARM Linux 2010-08-17 14:12 ` Tony Lindgren 2010-08-17 14:12 ` Tony Lindgren 2010-08-17 15:40 ` Russell King - ARM Linux 2010-08-17 15:40 ` Russell King - ARM Linux 2010-08-19 7:38 ` Tony Lindgren 2010-08-19 7:38 ` Tony Lindgren 2010-08-19 9:38 ` Bryan Wu 2010-08-19 9:38 ` Bryan Wu 2010-08-19 9:57 ` Tony Lindgren 2010-08-19 9:57 ` Tony Lindgren 2010-08-19 10:20 ` Russell King - ARM Linux 2010-08-19 10:20 ` Russell King - ARM Linux 2010-08-20 12:06 ` Tony Lindgren 2010-08-20 12:06 ` Tony Lindgren 2010-08-30 22:55 ` Tony Lindgren 2010-08-30 22:55 ` Tony Lindgren 2010-09-02 13:36 ` Russell King - ARM Linux 2010-09-02 13:36 ` Russell King - ARM Linux 2010-09-02 16:16 ` Tony Lindgren 2010-09-02 16:16 ` Tony Lindgren 2010-09-02 16:18 ` [PATCH 1/6] ARM: Add inline function smp_on_up() for early init testing Tony Lindgren 2010-09-02 16:18 ` Tony Lindgren 2010-09-02 17:08 ` Russell King - ARM Linux 2010-09-02 17:08 ` Russell King - ARM Linux 2010-09-02 17:15 ` [PATCH 0/6] " Tony Lindgren 2010-09-02 17:15 ` Tony Lindgren 2010-09-02 17:42 ` [PATCH 1/6] " Tony Lindgren 2010-09-02 17:42 ` Tony Lindgren 2010-09-02 19:26 ` [PATCH 1/6] ARM: Add inline function smp_cpu() " Tony Lindgren 2010-09-02 19:26 ` Tony Lindgren 2010-09-03 0:08 ` Tony Lindgren 2010-09-03 0:08 ` Tony Lindgren 2010-09-03 2:22 ` Tony Lindgren 2010-09-03 2:22 ` Tony Lindgren 2010-09-03 8:58 ` Will Deacon 2010-09-03 9:02 ` Russell King - ARM Linux 2010-09-03 9:02 ` Russell King - ARM Linux 2010-09-03 9:07 ` Will Deacon 2010-09-03 9:07 ` Will Deacon 2010-09-03 8:58 ` Will Deacon 2010-09-03 12:12 ` Shilimkar, Santosh 2010-09-03 12:12 ` Shilimkar, Santosh 2010-09-03 12:23 ` Will Deacon 2010-09-03 12:23 ` Will Deacon 2010-09-03 12:31 ` Shilimkar, Santosh 2010-09-03 12:31 ` Shilimkar, Santosh 2010-09-05 1:53 ` Michał Nazarewicz 2010-09-05 1:53 ` Michał Nazarewicz 2010-09-03 12:09 ` [PATCH 1/6] ARM: Add inline function smp_on_up() " Shilimkar, Santosh 2010-09-03 12:09 ` Shilimkar, Santosh 2010-09-06 10:17 ` Bryan Wu 2010-09-06 10:17 ` Bryan Wu 2010-09-08 3:26 ` Tony Lindgren 2010-09-08 3:26 ` Tony Lindgren 2010-09-08 20:26 ` Tony Lindgren 2010-09-08 20:26 ` Tony Lindgren 2010-09-09 3:45 ` Bryan Wu 2010-09-09 3:45 ` Bryan Wu 2010-09-02 16:19 ` [PATCH 2/6] ARM: Use SMP and UP macros for cacheflush Tony Lindgren 2010-09-02 16:19 ` Tony Lindgren 2010-09-03 11:57 ` Shilimkar, Santosh 2010-09-03 11:57 ` Shilimkar, Santosh 2010-09-04 10:57 ` Russell King - ARM Linux 2010-09-04 10:57 ` Russell King - ARM Linux 2010-09-04 11:01 ` Shilimkar, Santosh 2010-09-04 11:01 ` Shilimkar, Santosh 2010-09-02 16:20 ` [PATCH 3/6] ARM: Fix v7wbi_tlb_flags for SMP on UP Tony Lindgren 2010-09-02 16:20 ` Tony Lindgren 2010-09-02 16:25 ` Russell King - ARM Linux 2010-09-02 16:25 ` Russell King - ARM Linux 2010-09-02 16:34 ` Tony Lindgren 2010-09-02 16:34 ` Tony Lindgren 2010-09-02 23:47 ` Tony Lindgren 2010-09-02 23:47 ` Tony Lindgren 2010-09-03 9:07 ` Russell King - ARM Linux 2010-09-03 9:07 ` Russell King - ARM Linux 2010-09-03 9:10 ` Russell King - ARM Linux 2010-09-03 9:10 ` Russell King - ARM Linux 2010-09-03 17:04 ` Tony Lindgren 2010-09-03 17:04 ` Tony Lindgren 2010-09-03 19:36 ` Russell King - ARM Linux 2010-09-03 19:36 ` Russell King - ARM Linux 2010-09-06 11:46 ` Catalin Marinas 2010-09-06 11:46 ` Catalin Marinas 2010-09-06 15:34 ` Russell King - ARM Linux 2010-09-06 15:34 ` Russell King - ARM Linux 2010-09-06 15:53 ` Catalin Marinas 2010-09-06 15:53 ` Catalin Marinas 2010-09-06 16:36 ` Russell King - ARM Linux 2010-09-06 16:36 ` Russell King - ARM Linux 2010-09-06 17:11 ` Catalin Marinas 2010-09-06 17:11 ` Catalin Marinas 2010-09-02 16:21 ` [PATCH 4/6] ARM: Do not call test_for_ipi or test_for_ltrirq on UP systems Tony Lindgren 2010-09-02 16:21 ` Tony Lindgren 2010-09-03 12:00 ` Shilimkar, Santosh 2010-09-03 12:00 ` Shilimkar, Santosh 2010-09-04 10:55 ` Russell King - ARM Linux 2010-09-04 10:55 ` Russell King - ARM Linux 2010-09-04 10:55 ` Russell King - ARM Linux 2010-09-04 10:55 ` Russell King - ARM Linux 2010-09-02 16:22 ` [PATCH 5/6] ARM: Don't set TLB ops broadcasting on UP ARMv7 Tony Lindgren 2010-09-02 16:22 ` Tony Lindgren 2010-09-02 16:57 ` Russell King - ARM Linux 2010-09-02 16:57 ` Russell King - ARM Linux 2010-09-02 17:21 ` Tony Lindgren 2010-09-02 17:21 ` Tony Lindgren 2010-09-02 18:01 ` Russell King - ARM Linux 2010-09-02 18:01 ` Russell King - ARM Linux 2010-09-02 18:13 ` Tony Lindgren 2010-09-02 18:13 ` Tony Lindgren 2010-09-02 18:18 ` Russell King - ARM Linux 2010-09-02 18:18 ` Russell King - ARM Linux 2010-09-02 16:23 ` [PATCH 6/6] omap: Fix SMP on UP interrupt handling for multi-omap Tony Lindgren 2010-09-02 16:23 ` Tony Lindgren 2010-09-02 19:30 ` Tony Lindgren 2010-09-02 19:30 ` Tony Lindgren 2010-09-03 12:15 ` Shilimkar, Santosh 2010-09-03 12:15 ` Shilimkar, Santosh 2010-09-08 3:30 ` Tony Lindgren 2010-09-08 3:30 ` Tony Lindgren 2010-09-03 12:06 ` Shilimkar, Santosh 2010-09-03 12:06 ` Shilimkar, Santosh 2010-09-04 11:05 ` Russell King - ARM Linux 2010-09-04 11:05 ` Russell King - ARM Linux 2010-09-04 11:22 ` Shilimkar, Santosh 2010-09-04 11:22 ` Shilimkar, Santosh 2010-09-03 4:20 ` [PATCH 0/4] Hacks to allow booting ARM SMP kernel on UP ARMv7 Bryan Wu 2010-09-03 4:20 ` Bryan Wu 2010-09-03 7:46 ` Russell King - ARM Linux 2010-09-03 7:46 ` Russell King - ARM Linux 2010-09-06 9:28 ` Catalin Marinas 2010-09-06 9:28 ` Catalin Marinas 2010-09-06 9:34 ` Russell King - ARM Linux 2010-09-06 9:34 ` Russell King - ARM Linux 2010-09-06 9:38 ` Catalin Marinas 2010-09-06 9:38 ` Catalin Marinas 2010-09-06 10:06 ` Russell King - ARM Linux 2010-09-06 10:06 ` Russell King - ARM Linux 2010-09-06 10:39 ` Catalin Marinas 2010-09-06 10:39 ` Catalin Marinas 2010-09-02 13:33 ` Russell King - ARM Linux 2010-09-02 13:33 ` Russell King - ARM Linux 2010-09-03 1:39 ` Tony Lindgren 2010-09-03 1:39 ` Tony Lindgren 2010-08-23 16:59 ` Will Deacon 2010-08-23 16:59 ` Will Deacon 2010-08-30 22:53 ` Tony Lindgren 2010-08-30 22:53 ` Tony Lindgren 2010-09-06 10:44 ` Russell King - ARM Linux 2010-09-06 10:44 ` Russell King - ARM Linux 2010-09-06 15:16 ` Catalin Marinas 2010-09-06 15:16 ` Catalin Marinas 2010-09-06 18:03 ` Tony Lindgren 2010-09-06 18:03 ` Tony Lindgren 2010-09-08 3:09 ` Tony Lindgren 2010-09-08 3:09 ` Tony Lindgren 2010-09-08 3:12 ` [PATCH] ARM: Check for is_smp for tlb_ops and cache_ops boardcast Tony Lindgren 2010-09-08 3:12 ` Tony Lindgren 2010-09-08 3:14 ` [PATCH] ARM: Don't try to send IPI on UP systems with CONFIG_SMP Tony Lindgren 2010-09-08 3:14 ` Tony Lindgren 2010-09-08 3:17 ` [PATCH] omap: Fix CONFIG_LOCAL_TIMERS initialization for multi-omap Tony Lindgren 2010-09-08 3:17 ` Tony Lindgren 2010-09-08 7:26 ` Shilimkar, Santosh 2010-09-08 7:26 ` Shilimkar, Santosh 2010-09-08 7:30 ` [PATCH] ARM: Don't try to send IPI on UP systems with CONFIG_SMP Shilimkar, Santosh 2010-09-08 7:30 ` Shilimkar, Santosh 2010-09-08 8:56 ` Russell King - ARM Linux 2010-09-08 8:56 ` Russell King - ARM Linux 2010-09-08 19:32 ` Tony Lindgren 2010-09-08 19:32 ` Tony Lindgren 2010-10-05 22:19 ` [PATCH] ARM: Check for is_smp for tlb_ops and cache_ops boardcast Tony Lindgren 2010-10-05 22:19 ` Tony Lindgren 2010-10-05 22:33 ` Russell King - ARM Linux 2010-10-05 22:33 ` Russell King - ARM Linux 2010-10-06 14:44 ` Tony Lindgren 2010-10-06 14:44 ` Tony Lindgren 2010-10-06 22:33 ` Russell King - ARM Linux 2010-10-06 22:33 ` Russell King - ARM Linux 2010-10-06 23:07 ` Tony Lindgren 2010-10-06 23:07 ` Tony Lindgren 2010-09-14 18:59 ` [PATCH] ARM: Handle __flush_icache_all for CONFIG_SMP_ON_UP Tony Lindgren 2010-09-14 18:59 ` Tony Lindgren 2010-09-14 19:03 ` [PATCH] omap: Update omap3_defconfig to work with SMP_ON_UP Tony Lindgren 2010-09-14 19:03 ` Tony Lindgren 2010-09-14 19:05 ` [PATCH] omap: Update omap3_defconfig for omap2 Tony Lindgren 2010-09-14 19:05 ` Tony Lindgren 2010-09-14 19:17 ` [PATCH] omap: Update omap3_defconfig to work with SMP_ON_UP Shilimkar, Santosh 2010-09-14 19:17 ` Shilimkar, Santosh 2010-09-14 20:27 ` Tony Lindgren 2010-09-14 20:27 ` Tony Lindgren 2010-09-15 6:11 ` Shilimkar, Santosh 2010-09-15 6:11 ` Shilimkar, Santosh 2010-09-15 16:11 ` Tony Lindgren 2010-09-15 16:11 ` Tony Lindgren 2010-09-15 18:25 ` Shilimkar, Santosh 2010-09-15 18:25 ` Shilimkar, Santosh 2010-09-15 23:15 ` Tony Lindgren 2010-09-15 23:15 ` Tony Lindgren 2010-09-16 17:05 ` [PATCH] ARM: Handle __flush_icache_all for CONFIG_SMP_ON_UP Catalin Marinas 2010-09-16 17:05 ` Catalin Marinas 2010-09-21 16:16 ` Tony Lindgren 2010-09-21 16:16 ` Tony Lindgren
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