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From: Mike Travis <travis@sgi.com>
To: Ingo Molnar <mingo@elte.hu>, Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <andi@firstfloor.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	davej@codemonkey.org.uk, David Miller <davem@davemloft.net>,
	Eric Dumazet <dada1@cosmosbay.com>,
	Jack Steiner <steiner@sgi.com>,
	Jeremy Fitzhardinge <jeremy@goop.org>, Jes Sorensen <jes@sgi.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	peterz@infradead.org, Thomas Gleixner <tglx@linutronix.de>,
	Yinghai Lu <yhlu.kernel@gmail.com>,
	IA64 <linux-ia64@vger.kernel.org>,
	PowerPC <linuxppc-dev@ozlabs.org>,
	S390 <linux-s390@vger.kernel.org>,
	SPARC <sparclinux@vger.kernel.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 14/35] cpumask: make nr_cpu_ids valid in all configurations.
Date: Mon, 20 Oct 2008 10:03:33 -0700	[thread overview]
Message-ID: <20081020170321.535939000@polaris-admin.engr.sgi.com> (raw)
In-Reply-To: <20081020170319.539427000@polaris-admin.engr.sgi.com>

[-- Attachment #1: cpumask:always-have-nr_cpu_ids.patch --]
[-- Type: text/plain, Size: 2159 bytes --]

nr_cpu_ids is the (badly named) runtime limit on possible CPU numbers;
ie. the variable version of NR_CPUS.

This makes is valid in all configs, including UP.

From: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
---
 include/linux/cpumask.h |   10 ++++++++--
 init/main.c             |    7 +++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

--- test-compile.orig/include/linux/cpumask.h
+++ test-compile/include/linux/cpumask.h
@@ -195,6 +195,14 @@ extern cpumask_t _unused_cpumask_arg_;
 #define cpus_addr(src) ((src).bits)
 /* End deprecated region. */
 
+#if NR_CPUS <= BITS_PER_LONG
+/* Constant is usually more efficient than a variable for small NR_CPUS */
+#define nr_cpu_ids NR_CPUS
+#else
+/* Starts at NR_CPUS until we know better. */
+extern int nr_cpu_ids;
+#endif /* NR_CPUS > BITS_PER_LONG */
+
 static inline void cpumask_set_cpu(int cpu, volatile struct cpumask *dstp)
 {
 	set_bit(cpu, dstp->bits);
@@ -434,7 +442,6 @@ extern cpumask_t cpu_mask_all;
 
 #if NR_CPUS == 1
 
-#define nr_cpu_ids			1
 #define first_cpu(src)			({ (void)(src); 0; })
 #define next_cpu(n, src)		({ (void)(src); 1; })
 #define cpumask_next_and(n, srcp, andp)	({ (void)(srcp), (void)(andp); 1; })
@@ -447,7 +454,6 @@ extern cpumask_t cpu_mask_all;
 
 #else /* NR_CPUS > 1 */
 
-extern int nr_cpu_ids;
 int __first_cpu(const cpumask_t *srcp);
 int __next_cpu(int n, const cpumask_t *srcp);
 int cpumask_next_and(int n, const cpumask_t *srcp, const cpumask_t *andp);
--- test-compile.orig/init/main.c
+++ test-compile/init/main.c
@@ -373,6 +373,8 @@ EXPORT_SYMBOL(cpu_mask_all);
 #endif
 
 /* Setup number of possible processor ids */
+/* nr_cpu_ids is a real variable for large NR_CPUS. */
+#ifndef nr_cpu_ids
 int nr_cpu_ids __read_mostly = NR_CPUS;
 EXPORT_SYMBOL(nr_cpu_ids);
 
@@ -386,6 +388,11 @@ void __init setup_nr_cpu_ids(void)
 
 	nr_cpu_ids = highest_cpu + 1;
 }
+#else
+void __init setup_nr_cpu_ids(void)
+{
+}
+#endif /* ... nr_cpu_ids is a constant. */
 
 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;

-- 

  parent reply	other threads:[~2008-10-20 17:17 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-20 17:03 [PATCH 00/35] cpumask: Replace cpumask_t with struct cpumask Mike Travis
2008-10-20 17:03 ` [PATCH 01/35] x86: clean up speedctep-centrino and reduce cpumask_t usage Mike Travis
2008-10-21  0:09   ` Stephen Rothwell
2008-10-21 12:28     ` Mike Travis
2008-10-20 17:03 ` [PATCH 02/35] cpumask: remove min from first_cpu/next_cpu Mike Travis
2008-10-20 17:03 ` [PATCH 03/35] cpumask: add for_each_cpu_mask_and function Mike Travis
2008-10-20 17:03 ` [PATCH 04/35] x86 smp: modify send_IPI_mask interface to accept cpumask_t pointers Mike Travis
2008-10-20 17:03 ` [PATCH 05/35] sched: Reduce stack size requirements in kernel/sched.c Mike Travis
2008-10-20 17:03 ` [PATCH 06/35] cpumask: introduce struct cpumask Mike Travis
2008-10-20 17:03 ` [PATCH 07/35] cpumask: change cpumask_scnprintf, cpumask_parse_user, cpulist_parse, and cpulist_scnprintf to take pointers Mike Travis
2008-10-20 17:03 ` [PATCH 08/35] cpumask: cpumask_size() Mike Travis
2008-10-20 17:03 ` [PATCH 09/35] cpumask: add cpumask_copy() Mike Travis
2008-10-20 17:03 ` [PATCH 10/35] cpumask: introduce cpumask_var_t for local cpumask vars Mike Travis
2008-10-20 17:03 ` [PATCH 11/35] x86: enable MAXSMP Mike Travis
2008-10-20 17:03 ` [PATCH 12/35] cpumask: make CONFIG_NR_CPUS always valid Mike Travis
2008-10-20 17:03 ` [PATCH 13/35] cpumask: use setup_nr_cpu_ids() instead of direct assignment Mike Travis
2008-10-20 17:03 ` Mike Travis [this message]
2008-10-20 17:03 ` [PATCH 15/35] cpumask: prepare for iterators to only go to nr_cpu_ids Mike Travis
2008-10-20 17:03 ` [PATCH 16/35] percpu: fix percpu accessors to potentially !cpu_possible() cpus Mike Travis
2008-10-20 17:03 ` [PATCH 17/35] cpumask: make nr_cpu_ids the actual limit on bitmap size Mike Travis
2008-10-20 17:03 ` [PATCH 18/35] cpumask: add nr_cpumask_bits Mike Travis
2008-10-21 12:26   ` Rusty Russell
2008-10-21 13:53     ` Mike Travis
2008-10-20 17:03 ` [PATCH 19/35] cpumask: use cpumask_bits() everywhere Mike Travis
2008-10-20 17:03 ` [PATCH 20/35] cpumask: cpumask_of(): cpumask_of_cpu() which returns a pointer Mike Travis
2008-10-20 17:03 ` [PATCH 21/35] cpumask: for_each_cpu(): for_each_cpu_mask which takes " Mike Travis
2008-10-20 17:03 ` [PATCH 22/35] cpumask: cpumask_first/cpumask_next Mike Travis
2008-10-20 17:03 ` [PATCH 23/35] cpumask: deprecate any_online_cpu() in favour of cpumask_any/cpumask_any_and Mike Travis
2008-10-20 17:03 ` [PATCH 24/35] cpumask: cpumask_any_but() Mike Travis
2008-10-20 17:03 ` [PATCH 25/35] cpumask: Deprecate CPUMASK_ALLOC etc in favor of cpumask_var_t Mike Travis
2008-10-20 17:03 ` [PATCH 26/35] cpumask: get rid of boutique sched.c allocations, use cpumask_var_t Mike Travis
2008-10-20 17:03 ` [PATCH 27/35] cpumask: to_cpumask() Mike Travis
2008-10-20 17:03 ` [PATCH 28/35] cpumask: accessors to manipulate possible/present/online/active maps Mike Travis
2008-10-20 17:03 ` [PATCH 29/35] cpumask: Use accessors code Mike Travis
2008-10-20 17:03 ` [PATCH 30/35] cpumask: CONFIG_BITS_ALL, CONFIG_BITS_NONE and CONFIG_BITS_CPU0 Mike Travis
2008-10-20 17:03 ` [PATCH 31/35] cpumask: switch over to cpu_online/possible/active/present_mask Mike Travis
2008-10-20 17:03 ` [PATCH 32/35] cpumask: cpu_all_mask and cpu_none_mask Mike Travis
2008-10-20 17:03 ` [PATCH 33/35] cpumask: reorder header to minimize separate #ifdefs Mike Travis
2008-10-20 17:03 ` [PATCH 34/35] cpumask: debug options for cpumasks Mike Travis
2008-10-20 17:03 ` [PATCH 35/35] cpumask: smp_call_function_many() Mike Travis

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