* [PATCHv4 0/3] enable nr_cpus for powerpc
@ 2018-03-12 4:43 Pingfan Liu
2018-03-12 4:43 ` [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt Pingfan Liu
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Pingfan Liu @ 2018-03-12 4:43 UTC (permalink / raw)
To: linuxppc-dev; +Cc: cascardo, gpiccoli, kexec, paulus, mpe, benh
This topic has a very long history. It comes from Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
For v3: https://patchwork.ozlabs.org/patch/834860/
In this series, I separate and change the mapping between cpu logical id and hwid.
I hope we can acquire it for "kexec -p"
Mahesh Salgaonkar (1):
ppc64 boot: Wait for boot cpu to show up if nr_cpus limit is about to
hit.
Pingfan Liu (2):
powerpc, cpu: partially unbind the mapping between cpu logical id and
its seq in dt
powerpc, cpu: handling the special case when boot_cpuid greater than
nr_cpus
arch/powerpc/include/asm/paca.h | 3 +++
arch/powerpc/include/asm/smp.h | 1 +
arch/powerpc/kernel/paca.c | 19 ++++++++++++++-----
arch/powerpc/kernel/prom.c | 25 ++++++++++++++-----------
arch/powerpc/kernel/setup-common.c | 35 +++++++++++++++++++++++++++++++++--
5 files changed, 65 insertions(+), 18 deletions(-)
--
2.7.4
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^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt 2018-03-12 4:43 [PATCHv4 0/3] enable nr_cpus for powerpc Pingfan Liu @ 2018-03-12 4:43 ` Pingfan Liu 2018-03-13 2:58 ` Benjamin Herrenschmidt 2018-03-13 5:06 ` kbuild test robot 2018-03-12 4:43 ` [PATCHv4 2/3] powerpc, cpu: handling the special case when boot_cpuid greater than nr_cpus Pingfan Liu 2018-03-12 4:43 ` [PATCHv4 3/3] ppc64 boot: Wait for boot cpu to show up if nr_cpus limit is about to hit Pingfan Liu 2 siblings, 2 replies; 7+ messages in thread From: Pingfan Liu @ 2018-03-12 4:43 UTC (permalink / raw) To: linuxppc-dev; +Cc: cascardo, gpiccoli, kexec, paulus, mpe, benh For kexec -p, the boot cpu can be not the cpu0, this causes the problem to alloc paca[]. In theory, there is no requirement to assign cpu's logical id as its present seq by device tree. But we have something like cpu_first_thread_sibling(), which makes assumption on the mapping inside a core. Hence partially changing the mapping, i.e. unbind the mapping of core while keep the mapping inside a core. After this patch, boot-cpu will always be mapped into the range [0,threads_per_core). Signed-off-by: Pingfan Liu <kernelfans@gmail.com> --- arch/powerpc/include/asm/smp.h | 1 + arch/powerpc/kernel/prom.c | 25 ++++++++++++++----------- arch/powerpc/kernel/setup-common.c | 21 +++++++++++++++++++++ 3 files changed, 36 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h index fac963e..1299100 100644 --- a/arch/powerpc/include/asm/smp.h +++ b/arch/powerpc/include/asm/smp.h @@ -30,6 +30,7 @@ #include <asm/percpu.h> extern int boot_cpuid; +extern int boot_cpuhwid; extern int spinning_secondaries; extern void cpu_die(void); diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index da67606..d0ebb25 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -315,8 +315,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node, const __be32 *intserv; int i, nthreads; int len; - int found = -1; - int found_thread = 0; + bool found = false; /* We are scanning "cpu" nodes only */ if (type == NULL || strcmp(type, "cpu") != 0) @@ -341,8 +340,11 @@ static int __init early_init_dt_scan_cpus(unsigned long node, if (fdt_version(initial_boot_params) >= 2) { if (be32_to_cpu(intserv[i]) == fdt_boot_cpuid_phys(initial_boot_params)) { - found = boot_cpu_count; - found_thread = i; + /* always map the boot-cpu logical id into the + * the range of [0, thread_per_core) + */ + boot_cpuid = i; + found = true; } } else { /* @@ -351,8 +353,10 @@ static int __init early_init_dt_scan_cpus(unsigned long node, * off secondary threads. */ if (of_get_flat_dt_prop(node, - "linux,boot-cpu", NULL) != NULL) - found = boot_cpu_count; + "linux,boot-cpu", NULL) != NULL) { + boot_cpuid = i; + found = true; + } } #ifdef CONFIG_SMP /* logical cpu id is always 0 on UP kernels */ @@ -361,13 +365,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node, } /* Not the boot CPU */ - if (found < 0) + if (!found) return 0; - DBG("boot cpu: logical %d physical %d\n", found, - be32_to_cpu(intserv[found_thread])); - boot_cpuid = found; - set_hard_smp_processor_id(found, be32_to_cpu(intserv[found_thread])); + boot_cpuhwid = be32_to_cpu(intserv[boot_cpuid]); + DBG("boot cpu: logical %d physical %d\n", boot_cpuid, boot_cpuhwid); + set_hard_smp_processor_id(boot_cpuid, boot_cpuhwid); /* * PAPR defines "logical" PVR values for cpus that diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 66f7cc6..1a67344 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -86,6 +86,7 @@ struct machdep_calls *machine_id; EXPORT_SYMBOL(machine_id); int boot_cpuid = -1; +int boot_cpuhwid = -1; EXPORT_SYMBOL_GPL(boot_cpuid); /* @@ -459,11 +460,17 @@ static void __init cpu_init_thread_core_maps(int tpc) void __init smp_setup_cpu_maps(void) { struct device_node *dn; + struct device_node *boot_dn = NULL; + bool handling_bootdn = true; int cpu = 0; int nthreads = 1; DBG("smp_setup_cpu_maps()\n"); +again: + /* E.g. kexec will not boot from the 1st core. So firstly loop to find out + * the dn of boot-cpu, and map them onto [0, nthreads) + */ for_each_node_by_type(dn, "cpu") { const __be32 *intserv; __be32 cpu_be; @@ -488,6 +495,16 @@ void __init smp_setup_cpu_maps(void) nthreads = len / sizeof(int); + if (handling_bootdn) { + if (boot_cpuid < nthreads && + be32_to_cpu(intserv[boot_cpuid]) == boot_cpuhwid) { + boot_dn = dn; + } + if (boot_dn == NULL) + continue; + } else if (dn == boot_dn) + continue; + for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) { bool avail; @@ -509,6 +526,10 @@ void __init smp_setup_cpu_maps(void) of_node_put(dn); break; } + if (handling_bootdn) { + handling_bootdn = false; + goto again; + } } /* If no SMT supported, nthreads is forced to 1 */ -- 2.7.4 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt 2018-03-12 4:43 ` [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt Pingfan Liu @ 2018-03-13 2:58 ` Benjamin Herrenschmidt 2018-03-14 2:02 ` Pingfan Liu 2018-03-13 5:06 ` kbuild test robot 1 sibling, 1 reply; 7+ messages in thread From: Benjamin Herrenschmidt @ 2018-03-13 2:58 UTC (permalink / raw) To: Pingfan Liu, linuxppc-dev; +Cc: cascardo, gpiccoli, kexec, paulus, mpe On Mon, 2018-03-12 at 12:43 +0800, Pingfan Liu wrote: > For kexec -p, the boot cpu can be not the cpu0, this causes the problem > to alloc paca[]. In theory, there is no requirement to assign cpu's logical > id as its present seq by device tree. But we have something like > cpu_first_thread_sibling(), which makes assumption on the mapping inside > a core. Hence partially changing the mapping, i.e. unbind the mapping of > core while keep the mapping inside a core. After this patch, boot-cpu > will always be mapped into the range [0,threads_per_core). I'm ok with the idea but not fan of the implementation: > Signed-off-by: Pingfan Liu <kernelfans@gmail.com> > --- > arch/powerpc/include/asm/smp.h | 1 + > arch/powerpc/kernel/prom.c | 25 ++++++++++++++----------- > arch/powerpc/kernel/setup-common.c | 21 +++++++++++++++++++++ > 3 files changed, 36 insertions(+), 11 deletions(-) > > diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h > index fac963e..1299100 100644 > --- a/arch/powerpc/include/asm/smp.h > +++ b/arch/powerpc/include/asm/smp.h > @@ -30,6 +30,7 @@ > #include <asm/percpu.h> > > extern int boot_cpuid; > +extern int boot_cpuhwid; > extern int spinning_secondaries; > > extern void cpu_die(void); > diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c > index da67606..d0ebb25 100644 > --- a/arch/powerpc/kernel/prom.c > +++ b/arch/powerpc/kernel/prom.c > @@ -315,8 +315,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node, > const __be32 *intserv; > int i, nthreads; > int len; > - int found = -1; > - int found_thread = 0; > + bool found = false; > > /* We are scanning "cpu" nodes only */ > if (type == NULL || strcmp(type, "cpu") != 0) > @@ -341,8 +340,11 @@ static int __init early_init_dt_scan_cpus(unsigned long node, > if (fdt_version(initial_boot_params) >= 2) { > if (be32_to_cpu(intserv[i]) == > fdt_boot_cpuid_phys(initial_boot_params)) { > - found = boot_cpu_count; > - found_thread = i; > + /* always map the boot-cpu logical id into the > + * the range of [0, thread_per_core) > + */ > + boot_cpuid = i; > + found = true; > } Call it boot_thread_id > } else { > /* > @@ -351,8 +353,10 @@ static int __init early_init_dt_scan_cpus(unsigned long node, > * off secondary threads. > */ > if (of_get_flat_dt_prop(node, > - "linux,boot-cpu", NULL) != NULL) > - found = boot_cpu_count; > + "linux,boot-cpu", NULL) != NULL) { > + boot_cpuid = i; > + found = true; > + } > } > #ifdef CONFIG_SMP > /* logical cpu id is always 0 on UP kernels */ > @@ -361,13 +365,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node, > } > > /* Not the boot CPU */ > - if (found < 0) > + if (!found) > return 0; > > - DBG("boot cpu: logical %d physical %d\n", found, > - be32_to_cpu(intserv[found_thread])); > - boot_cpuid = found; > - set_hard_smp_processor_id(found, be32_to_cpu(intserv[found_thread])); > + boot_cpuhwid = be32_to_cpu(intserv[boot_cpuid]); > + DBG("boot cpu: logical %d physical %d\n", boot_cpuid, boot_cpuhwid); > + set_hard_smp_processor_id(boot_cpuid, boot_cpuhwid); > > /* > * PAPR defines "logical" PVR values for cpus that > diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c > index 66f7cc6..1a67344 100644 > --- a/arch/powerpc/kernel/setup-common.c > +++ b/arch/powerpc/kernel/setup-common.c > @@ -86,6 +86,7 @@ struct machdep_calls *machine_id; > EXPORT_SYMBOL(machine_id); > > int boot_cpuid = -1; > +int boot_cpuhwid = -1; > EXPORT_SYMBOL_GPL(boot_cpuid); > > /* > @@ -459,11 +460,17 @@ static void __init cpu_init_thread_core_maps(int tpc) > void __init smp_setup_cpu_maps(void) > { > struct device_node *dn; > + struct device_node *boot_dn = NULL; > + bool handling_bootdn = true; > int cpu = 0; > int nthreads = 1; > > DBG("smp_setup_cpu_maps()\n"); > > +again: > + /* E.g. kexec will not boot from the 1st core. So firstly loop to find out > + * the dn of boot-cpu, and map them onto [0, nthreads) > + */ > for_each_node_by_type(dn, "cpu") { > const __be32 *intserv; > __be32 cpu_be; > @@ -488,6 +495,16 @@ void __init smp_setup_cpu_maps(void) > > nthreads = len / sizeof(int); > > + if (handling_bootdn) { > + if (boot_cpuid < nthreads && > + be32_to_cpu(intserv[boot_cpuid]) == boot_cpuhwid) { > + boot_dn = dn; > + } > + if (boot_dn == NULL) > + continue; > + } else if (dn == boot_dn) > + continue; > + > for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) { > bool avail; > > @@ -509,6 +526,10 @@ void __init smp_setup_cpu_maps(void) > of_node_put(dn); > break; > } > + if (handling_bootdn) { > + handling_bootdn = false; > + goto again; > + } > } You don't need that "again" loop and "handling_bootdn" weird boolean. Instead, start with cpu = 1 instead of cpu = 0, and rename it to "next_cpu". Then, before the thread loop, check if we are on the same core as boot_cpuhwid: if (same_core_as_boot_cpu(intserv)) { cpu = 0; } else if (next_cpu < nr_cpus_ids) { cpu = next_cpu++; } else { of_node_put(dn); break; } > > /* If no SMT supported, nthreads is forced to 1 */ _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt 2018-03-13 2:58 ` Benjamin Herrenschmidt @ 2018-03-14 2:02 ` Pingfan Liu 0 siblings, 0 replies; 7+ messages in thread From: Pingfan Liu @ 2018-03-14 2:02 UTC (permalink / raw) To: Benjamin Herrenschmidt Cc: cascardo, gpiccoli, kexec, paulus, Michael Ellerman, linuxppc-dev On Tue, Mar 13, 2018 at 10:58 AM, Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote: > On Mon, 2018-03-12 at 12:43 +0800, Pingfan Liu wrote: >> For kexec -p, the boot cpu can be not the cpu0, this causes the problem >> to alloc paca[]. In theory, there is no requirement to assign cpu's logical >> id as its present seq by device tree. But we have something like >> cpu_first_thread_sibling(), which makes assumption on the mapping inside >> a core. Hence partially changing the mapping, i.e. unbind the mapping of >> core while keep the mapping inside a core. After this patch, boot-cpu >> will always be mapped into the range [0,threads_per_core). > > I'm ok with the idea but not fan of the implementation: > >> Signed-off-by: Pingfan Liu <kernelfans@gmail.com> >> --- >> arch/powerpc/include/asm/smp.h | 1 + >> arch/powerpc/kernel/prom.c | 25 ++++++++++++++----------- >> arch/powerpc/kernel/setup-common.c | 21 +++++++++++++++++++++ >> 3 files changed, 36 insertions(+), 11 deletions(-) >> >> diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h >> index fac963e..1299100 100644 >> --- a/arch/powerpc/include/asm/smp.h >> +++ b/arch/powerpc/include/asm/smp.h >> @@ -30,6 +30,7 @@ >> #include <asm/percpu.h> >> >> extern int boot_cpuid; >> +extern int boot_cpuhwid; >> extern int spinning_secondaries; >> >> extern void cpu_die(void); >> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c >> index da67606..d0ebb25 100644 >> --- a/arch/powerpc/kernel/prom.c >> +++ b/arch/powerpc/kernel/prom.c >> @@ -315,8 +315,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node, >> const __be32 *intserv; >> int i, nthreads; >> int len; >> - int found = -1; >> - int found_thread = 0; >> + bool found = false; >> >> /* We are scanning "cpu" nodes only */ >> if (type == NULL || strcmp(type, "cpu") != 0) >> @@ -341,8 +340,11 @@ static int __init early_init_dt_scan_cpus(unsigned long node, >> if (fdt_version(initial_boot_params) >= 2) { >> if (be32_to_cpu(intserv[i]) == >> fdt_boot_cpuid_phys(initial_boot_params)) { >> - found = boot_cpu_count; >> - found_thread = i; >> + /* always map the boot-cpu logical id into the >> + * the range of [0, thread_per_core) >> + */ >> + boot_cpuid = i; >> + found = true; >> } > > Call it boot_thread_id > But I think boot_cpuid has the meaning of global index, while the thread_id has the meaning of index in a core. >> } else { >> /* >> @@ -351,8 +353,10 @@ static int __init early_init_dt_scan_cpus(unsigned long node, >> * off secondary threads. >> */ >> if (of_get_flat_dt_prop(node, >> - "linux,boot-cpu", NULL) != NULL) >> - found = boot_cpu_count; >> + "linux,boot-cpu", NULL) != NULL) { >> + boot_cpuid = i; >> + found = true; >> + } >> } >> #ifdef CONFIG_SMP >> /* logical cpu id is always 0 on UP kernels */ >> @@ -361,13 +365,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node, >> } >> >> /* Not the boot CPU */ >> - if (found < 0) >> + if (!found) >> return 0; >> >> - DBG("boot cpu: logical %d physical %d\n", found, >> - be32_to_cpu(intserv[found_thread])); >> - boot_cpuid = found; >> - set_hard_smp_processor_id(found, be32_to_cpu(intserv[found_thread])); >> + boot_cpuhwid = be32_to_cpu(intserv[boot_cpuid]); >> + DBG("boot cpu: logical %d physical %d\n", boot_cpuid, boot_cpuhwid); >> + set_hard_smp_processor_id(boot_cpuid, boot_cpuhwid); >> >> /* >> * PAPR defines "logical" PVR values for cpus that >> diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c >> index 66f7cc6..1a67344 100644 >> --- a/arch/powerpc/kernel/setup-common.c >> +++ b/arch/powerpc/kernel/setup-common.c >> @@ -86,6 +86,7 @@ struct machdep_calls *machine_id; >> EXPORT_SYMBOL(machine_id); >> >> int boot_cpuid = -1; >> +int boot_cpuhwid = -1; >> EXPORT_SYMBOL_GPL(boot_cpuid); >> >> /* >> @@ -459,11 +460,17 @@ static void __init cpu_init_thread_core_maps(int tpc) >> void __init smp_setup_cpu_maps(void) >> { >> struct device_node *dn; >> + struct device_node *boot_dn = NULL; >> + bool handling_bootdn = true; >> int cpu = 0; >> int nthreads = 1; >> >> DBG("smp_setup_cpu_maps()\n"); >> >> +again: >> + /* E.g. kexec will not boot from the 1st core. So firstly loop to find out >> + * the dn of boot-cpu, and map them onto [0, nthreads) >> + */ >> for_each_node_by_type(dn, "cpu") { >> const __be32 *intserv; >> __be32 cpu_be; >> @@ -488,6 +495,16 @@ void __init smp_setup_cpu_maps(void) >> >> nthreads = len / sizeof(int); >> >> + if (handling_bootdn) { >> + if (boot_cpuid < nthreads && >> + be32_to_cpu(intserv[boot_cpuid]) == boot_cpuhwid) { >> + boot_dn = dn; >> + } >> + if (boot_dn == NULL) >> + continue; >> + } else if (dn == boot_dn) >> + continue; >> + >> for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) { >> bool avail; >> >> @@ -509,6 +526,10 @@ void __init smp_setup_cpu_maps(void) >> of_node_put(dn); >> break; >> } >> + if (handling_bootdn) { >> + handling_bootdn = false; >> + goto again; >> + } >> } > > You don't need that "again" loop and "handling_bootdn" weird boolean. > > Instead, start with cpu = 1 instead of cpu = 0, and rename it to > "next_cpu". > > Then, before the thread loop, check if we are on the same core > as boot_cpuhwid: > > if (same_core_as_boot_cpu(intserv)) { > cpu = 0; > } else if (next_cpu < nr_cpus_ids) { > cpu = next_cpu++; > } else { > of_node_put(dn); > break; > } > OK. Thanks for your review. Regards, Pingfan _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt 2018-03-12 4:43 ` [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt Pingfan Liu 2018-03-13 2:58 ` Benjamin Herrenschmidt @ 2018-03-13 5:06 ` kbuild test robot 1 sibling, 0 replies; 7+ messages in thread From: kbuild test robot @ 2018-03-13 5:06 UTC (permalink / raw) To: Pingfan Liu; +Cc: cascardo, gpiccoli, kexec, kbuild-all, linuxppc-dev [-- Attachment #1: Type: text/plain, Size: 2210 bytes --] Hi Pingfan, Thank you for the patch! Yet something to improve: [auto build test ERROR on v4.16-rc4] [also build test ERROR on next-20180309] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Pingfan-Liu/powerpc-cpu-partially-unbind-the-mapping-between-cpu-logical-id-and-its-seq-in-dt/20180313-034420 config: powerpc-pq2fads_defconfig (attached as .config) compiler: powerpc-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree make.cross ARCH=powerpc All errors (new ones prefixed by >>): >> arch/powerpc/kernel/prom.c:79:23: error: 'boot_cpu_count' defined but not used [-Werror=unused-variable] static int __initdata boot_cpu_count; ^~~~~~~~~~~~~~ cc1: all warnings being treated as errors vim +/boot_cpu_count +79 arch/powerpc/kernel/prom.c 9b6b563c Paul Mackerras 2005-10-06 71 9b6b563c Paul Mackerras 2005-10-06 72 #ifdef CONFIG_PPC64 28897731 Olof Johansson 2006-04-12 73 int __initdata iommu_is_off; 9b6b563c Paul Mackerras 2005-10-06 74 int __initdata iommu_force_on; cf00a8d1 Paul Mackerras 2005-10-31 75 unsigned long tce_alloc_start, tce_alloc_end; cd3db0c4 Benjamin Herrenschmidt 2010-07-06 76 u64 ppc64_rma_size; 9b6b563c Paul Mackerras 2005-10-06 77 #endif 03bf469a Benjamin Herrenschmidt 2011-05-11 78 static phys_addr_t first_memblock_size; 7ac87abb Matt Evans 2011-05-25 @79 static int __initdata boot_cpu_count; 9b6b563c Paul Mackerras 2005-10-06 80 :::::: The code at line 79 was first introduced by commit :::::: 7ac87abb8166b99584149fcfb2efef5773a078e9 powerpc: Fix early boot accounting of CPUs :::::: TO: Matt Evans <matt@ozlabs.org> :::::: CC: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation [-- Attachment #2: .config.gz --] [-- Type: application/gzip, Size: 14183 bytes --] [-- Attachment #3: Type: text/plain, Size: 143 bytes --] _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCHv4 2/3] powerpc, cpu: handling the special case when boot_cpuid greater than nr_cpus 2018-03-12 4:43 [PATCHv4 0/3] enable nr_cpus for powerpc Pingfan Liu 2018-03-12 4:43 ` [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt Pingfan Liu @ 2018-03-12 4:43 ` Pingfan Liu 2018-03-12 4:43 ` [PATCHv4 3/3] ppc64 boot: Wait for boot cpu to show up if nr_cpus limit is about to hit Pingfan Liu 2 siblings, 0 replies; 7+ messages in thread From: Pingfan Liu @ 2018-03-12 4:43 UTC (permalink / raw) To: linuxppc-dev; +Cc: cascardo, gpiccoli, kexec, paulus, mpe, benh For kexec -p, after boot_cpuid is mapping into the range of [0, threads_per_core), then if nr_cpus is small, we will have the bitmap [0,..., nr_cpus, ..., boot_cpuid, ...). This patch chooses cpus inside the range of [boot_cpuid - nr_cpus +1, ..., boot_cpuid] to be online. With this patch and the next, on a P9 machine with thread_per_core=4, and set nr_cpus=2 for the crash kernel. After taskset -c 11 sh -c "echo c > /proc/sysrq-trigger" Then kdump:/sys/devices/system/cpu# cat possible 2-3 kdump:/sys/devices/system/cpu# cat present 2-3 kdump:/sys/devices/system/cpu# cat online 2-3 Signed-off-by: Pingfan Liu <kernelfans@gmail.com> --- arch/powerpc/kernel/setup-common.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 1a67344..6920b5e 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -462,6 +462,8 @@ void __init smp_setup_cpu_maps(void) struct device_node *dn; struct device_node *boot_dn = NULL; bool handling_bootdn = true; + int head_thread = 0; + int online_cnt = 0; int cpu = 0; int nthreads = 1; @@ -499,13 +501,19 @@ void __init smp_setup_cpu_maps(void) if (boot_cpuid < nthreads && be32_to_cpu(intserv[boot_cpuid]) == boot_cpuhwid) { boot_dn = dn; + /* choose a bunch of continous threads */ + if (boot_cpuid > nr_cpu_ids - 1) { + head_thread = boot_cpuid - nr_cpu_ids + 1; + /* keep the mapping of logical and thread */ + cpu = head_thread; + } } if (boot_dn == NULL) continue; } else if (dn == boot_dn) continue; - for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) { + for (j = head_thread; j < nthreads && online_cnt < nr_cpu_ids; j++) { bool avail; DBG(" thread %d -> cpu %d (hard id %d)\n", @@ -520,13 +528,15 @@ void __init smp_setup_cpu_maps(void) set_hard_smp_processor_id(cpu, be32_to_cpu(intserv[j])); set_cpu_possible(cpu, true); cpu++; + online_cnt++; } - if (cpu >= nr_cpu_ids) { + if (online_cnt >= nr_cpu_ids) { of_node_put(dn); break; } if (handling_bootdn) { + head_thread = 0; handling_bootdn = false; goto again; } -- 2.7.4 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCHv4 3/3] ppc64 boot: Wait for boot cpu to show up if nr_cpus limit is about to hit. 2018-03-12 4:43 [PATCHv4 0/3] enable nr_cpus for powerpc Pingfan Liu 2018-03-12 4:43 ` [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt Pingfan Liu 2018-03-12 4:43 ` [PATCHv4 2/3] powerpc, cpu: handling the special case when boot_cpuid greater than nr_cpus Pingfan Liu @ 2018-03-12 4:43 ` Pingfan Liu 2 siblings, 0 replies; 7+ messages in thread From: Pingfan Liu @ 2018-03-12 4:43 UTC (permalink / raw) To: linuxppc-dev; +Cc: cascardo, gpiccoli, kexec, paulus, mpe, benh From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> The kernel boot parameter 'nr_cpus=' allows one to specify number of possible cpus in the system. In the normal scenario the first cpu (cpu0) that shows up is the boot cpu and hence it gets covered under nr_cpus limit. But this assumption will be broken in kdump scenario where kdump kenrel after a crash can boot up on an non-zero boot cpu. The paca structure allocation depends on value of nr_cpus and is indexed using logical cpu ids. This definetly will be an issue if boot cpu id > nr_cpus This patch modifies allocate_pacas() and smp_setup_cpu_maps() to accommodate boot cpu for the case where boot_cpuid > nr_cpu_ids. This change would help to reduce the memory reservation requirement for kdump on ppc64. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Tested-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com> Signed-off-by: Pingfan Liu <kernelfans@gmail.com> (separate the logical for cpu id mapping) Signed-off-by: Pingfan Liu <kernelfans@gmail.com> --- arch/powerpc/include/asm/paca.h | 3 +++ arch/powerpc/kernel/paca.c | 19 ++++++++++++++----- 2 files changed, 17 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index b62c310..49ab29d 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -49,6 +49,9 @@ extern unsigned int debug_smp_processor_id(void); /* from linux/smp.h */ #define get_lppaca() (get_paca()->lppaca_ptr) #define get_slb_shadow() (get_paca()->slb_shadow_ptr) +/* Maximum number of threads per core. */ +#define MAX_SMT 8 + struct task_struct; /* diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c index 95ffedf..13be6ab 100644 --- a/arch/powerpc/kernel/paca.c +++ b/arch/powerpc/kernel/paca.c @@ -209,6 +209,7 @@ void __init allocate_pacas(void) { u64 limit; int cpu; + unsigned int nr_cpus_aligned; #ifdef CONFIG_PPC_BOOK3S_64 /* @@ -220,20 +221,28 @@ void __init allocate_pacas(void) limit = ppc64_rma_size; #endif - paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids); + /* + * Alloc the paca[] align up to SMT threads. + * This will help us to prepare for a situation where + * boot cpu id > nr_cpus. + * We keep the schema of nr_cpus in kernel cmdline, but + * waste a bit memory + */ + nr_cpus_aligned = _ALIGN_UP(nr_cpu_ids, MAX_SMT); + paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpus_aligned); paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit)); memset(paca, 0, paca_size); printk(KERN_DEBUG "Allocated %u bytes for %u pacas at %p\n", - paca_size, nr_cpu_ids, paca); + paca_size, nr_cpus_aligned, paca); - allocate_lppacas(nr_cpu_ids, limit); + allocate_lppacas(nr_cpus_aligned, limit); - allocate_slb_shadows(nr_cpu_ids, limit); + allocate_slb_shadows(nr_cpus_aligned, limit); /* Can't use for_each_*_cpu, as they aren't functional yet */ - for (cpu = 0; cpu < nr_cpu_ids; cpu++) + for (cpu = 0; cpu < nr_cpus_aligned; cpu++) initialise_paca(&paca[cpu], cpu); } -- 2.7.4 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec ^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2018-03-14 2:03 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2018-03-12 4:43 [PATCHv4 0/3] enable nr_cpus for powerpc Pingfan Liu 2018-03-12 4:43 ` [PATCHv4 1/3] powerpc, cpu: partially unbind the mapping between cpu logical id and its seq in dt Pingfan Liu 2018-03-13 2:58 ` Benjamin Herrenschmidt 2018-03-14 2:02 ` Pingfan Liu 2018-03-13 5:06 ` kbuild test robot 2018-03-12 4:43 ` [PATCHv4 2/3] powerpc, cpu: handling the special case when boot_cpuid greater than nr_cpus Pingfan Liu 2018-03-12 4:43 ` [PATCHv4 3/3] ppc64 boot: Wait for boot cpu to show up if nr_cpus limit is about to hit Pingfan Liu
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