From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ashok Raj Date: Sun, 06 Jun 2004 20:27:23 +0000 Subject: Re: [lhcs-devel] Re: [RFC] don't create cpu/online sysfs file Message-Id: <20040606132723.A10563@unix-os.sc.intel.com> MIME-Version: 1 Content-Type: multipart/mixed; boundary="WIyZ46R2i8wDzkSu" List-Id: References: <1086390257.24915.132.camel@nighthawk> In-Reply-To: <1086390257.24915.132.camel@nighthawk> To: linux-ia64@vger.kernel.org --WIyZ46R2i8wDzkSu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sat, Jun 05, 2004 at 12:22:21PM -0700, Dave Hansen wrote: > knowledge about the system from the pure layout of sysfs. Waiting until > __cpu_disable() to tell the user that there was no possibility of the > cpu being offlined seems a bit late in the process. Your idea about the > cpuinfo file in sysfs is definitely right; it has *exactly* the > information that I'm trying to present. But, the current sysfs > guidelines tend to discourage single files with lots of information like > those in /proc. How does the attached patch look? I would try to keep away from proliferation of common->arch->platform code as little as possible. What i have done is send a hint for suppressing the control file creation based on what was set in the struct cpu, before calling register_cpu() by the arch specific topology_init() functions. No new __arch/__platform functions. here is the untested patch for PPC64, does this seem to do what you need? Cheers, ashok --WIyZ46R2i8wDzkSu Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="p00001_cpu_control_file.patch" D: This file provides ability for caller of register_cpu() to either create D: a control file, or not. This can be handy if a particular platform decides D: that certain CPU's are not removable. Hence would like to not create D: a control file. --- linux-2.6.7-rc2-root/arch/ppc64/kernel/sysfs.c | 10 ++++++++++ linux-2.6.7-rc2-root/drivers/base/cpu.c | 2 +- linux-2.6.7-rc2-root/include/linux/cpu.h | 1 + 3 files changed, 12 insertions(+), 1 deletion(-) diff -puN include/linux/cpu.h~cpu_control_file include/linux/cpu.h --- linux-2.6.7-rc2/include/linux/cpu.h~cpu_control_file 2004-06-06 12:54:02.319017387 -0700 +++ linux-2.6.7-rc2-root/include/linux/cpu.h 2004-06-06 12:56:01.663805054 -0700 @@ -27,6 +27,7 @@ struct cpu { int node_id; /* The node which contains the CPU */ + int not_removable; /* This cpu is not removable */ struct sys_device sysdev; }; diff -puN drivers/base/cpu.c~cpu_control_file drivers/base/cpu.c --- linux-2.6.7-rc2/drivers/base/cpu.c~cpu_control_file 2004-06-06 12:56:47.349375320 -0700 +++ linux-2.6.7-rc2-root/drivers/base/cpu.c 2004-06-06 12:58:12.390434486 -0700 @@ -75,7 +75,7 @@ int __init register_cpu(struct cpu *cpu, error = sysfs_create_link(&root->sysdev.kobj, &cpu->sysdev.kobj, kobject_name(&cpu->sysdev.kobj)); - if (!error) + if (!error && !cpu->not_removable) register_cpu_control(cpu); return error; } diff -puN arch/ppc64/kernel/sysfs.c~cpu_control_file arch/ppc64/kernel/sysfs.c --- linux-2.6.7-rc2/arch/ppc64/kernel/sysfs.c~cpu_control_file 2004-06-06 13:12:06.467033408 -0700 +++ linux-2.6.7-rc2-root/arch/ppc64/kernel/sysfs.c 2004-06-06 13:12:43.805919713 -0700 @@ -325,6 +325,16 @@ static int __init topology_init(void) #ifdef CONFIG_NUMA parent = &node_devices[cpu_to_node(cpu)]; #endif + /* + * For now, we just see if the system supports making + * the RTAS calls for CPU hotplug. But, there may be a + * more comprehensive way to do this for an individual + * CPU. For instance, the boot cpu might never be valid + * for hotplugging. + */ + if (systemcfg->platform == PLATFORM_PSERIES_LPAR) + cpu->not_removable=1; + register_cpu(c, cpu, parent); register_cpu_pmc(&c->sysdev); _ --WIyZ46R2i8wDzkSu--