| Message ID | 1533217359-11420-2-git-send-email-kernelfans@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] powerpc/cpuidle: dynamically register/unregister cpuidle_device during hotplug | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | next/apply_patch Successfully applied |
| snowpatch_ozlabs/checkpatch | success | Test checkpatch on branch next |
| snowpatch_ozlabs/build-ppc64le | success | Test build-ppc64le on branch next |
| snowpatch_ozlabs/build-ppc64be | success | Test build-ppc64be on branch next |
| snowpatch_ozlabs/build-ppc64e | warning | Test build-ppc64e on branch next |
| snowpatch_ozlabs/build-ppc32 | warning | Test build-ppc32 on branch next |
| snowpatch_ozlabs/apply_patch | success | next/apply_patch Successfully applied |
| snowpatch_ozlabs/checkpatch | success | Test checkpatch on branch next |
| snowpatch_ozlabs/build-ppc64le | success | Test build-ppc64le on branch next |
| snowpatch_ozlabs/build-ppc64be | success | Test build-ppc64be on branch next |
| snowpatch_ozlabs/build-ppc64e | fail | Test build-ppc64e on branch next |
| snowpatch_ozlabs/build-ppc32 | fail | Test build-ppc32 on branch next |
Hi Pingfan,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on powerpc/next]
[also build test ERROR on v4.18-rc7 next-20180802]
[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-cpuidle-dynamically-register-unregister-cpuidle_device-during-hotplug/20180803-151916
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-allnoconfig (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
GCC_VERSION=7.2.0 make.cross ARCH=powerpc
All errors (new ones prefixed by >>):
arch/powerpc/kernel/sysfs.c: In function 'unregister_ppc_cpu':
>> arch/powerpc/kernel/sysfs.c:1052:2: error: implicit declaration of function 'unregister_cpu'; did you mean 'register_cpu'? [-Werror=implicit-function-declaration]
unregister_cpu(container_of(get_cpu_device(cpu),
^~~~~~~~~~~~~~
register_cpu
cc1: all warnings being treated as errors
vim +1052 arch/powerpc/kernel/sysfs.c
1047
1048 int unregister_ppc_cpu(int cpu)
1049 {
1050 device_remove_file(&per_cpu(cpu_devices, cpu).dev,
1051 &dev_attr_physical_id);
> 1052 unregister_cpu(container_of(get_cpu_device(cpu),
1053 struct cpu, dev));
1054 return 0;
1055 }
1056
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Hi Pingfan, Pingfan Liu <kernelfans@gmail.com> writes: > Technically speaking, echo 1/0 > cpuX/online is only a subset of cpu > hotplug/unplug, i.e. add/remove. The latter one includes the physical > adding/removing of a cpu device. Some user space tools such as kexec-tools > resort to the event add/remove to automatically rebuild dtb. > If the dtb is not rebuilt correctly, we may hang on 2nd kernel due to > lack the info of boot-cpu-hwid in dtb. I notice you also sent a patch for ppc64_cpu to deal with CPUs being removed rather than just offlined. If I apply this patch then existing ppc64_cpu (without your other patch) will break. Is that right? cheers
On Sat, Aug 4, 2018 at 10:48 AM Michael Ellerman <mpe@ellerman.id.au> wrote: > > Hi Pingfan, > > Pingfan Liu <kernelfans@gmail.com> writes: > > Technically speaking, echo 1/0 > cpuX/online is only a subset of cpu > > hotplug/unplug, i.e. add/remove. The latter one includes the physical > > adding/removing of a cpu device. Some user space tools such as kexec-tools > > resort to the event add/remove to automatically rebuild dtb. > > If the dtb is not rebuilt correctly, we may hang on 2nd kernel due to > > lack the info of boot-cpu-hwid in dtb. > > I notice you also sent a patch for ppc64_cpu to deal with CPUs being > removed rather than just offlined. > > If I apply this patch then existing ppc64_cpu (without your other patch) > will break. Is that right? > Yes. Since removing cpu will make a hole in cpu map, but ppc64_cpu code takes the assumption that the cpu map is contiguous. Thanks, Pingfan
diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h index 8721fd0..e0597f2 100644 --- a/arch/powerpc/include/asm/setup.h +++ b/arch/powerpc/include/asm/setup.h @@ -40,6 +40,10 @@ static inline void pseries_big_endian_exceptions(void) {} static inline void pseries_little_endian_exceptions(void) {} #endif /* CONFIG_PPC_PSERIES */ +extern bool cpudev_is_dummy(int cpu); +extern int register_ppc_cpu(int cpu); +extern int unregister_ppc_cpu(int cpu); + void rfi_flush_enable(bool enable); /* These are bit flags */ diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h index 29ffaab..344180a 100644 --- a/arch/powerpc/include/asm/smp.h +++ b/arch/powerpc/include/asm/smp.h @@ -36,6 +36,7 @@ extern u32 *cpu_to_phys_id; extern void cpu_die(void); extern int cpu_to_chip_id(int cpu); +DECLARE_PER_CPU(struct cpu, cpu_devices); #ifdef CONFIG_SMP struct smp_ops_t { diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index 755dc98..2f6c9f9 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -27,7 +27,7 @@ #include <asm/lppaca.h> #endif -static DEFINE_PER_CPU(struct cpu, cpu_devices); +DEFINE_PER_CPU(struct cpu, cpu_devices); /* * SMT snooze delay stuff, 64-bit only for now @@ -1025,6 +1025,35 @@ static ssize_t show_physical_id(struct device *dev, } static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL); +/* unplugged cpu is true */ +bool cpudev_is_dummy(int cpu) +{ + struct cpu *c = &per_cpu(cpu_devices, cpu); + + return !kref_read(&c->dev.kobj.kref); +} + +/* create all files in sysfs, which can not be postponed till cpu online + * callbacks + */ +int register_ppc_cpu(int cpu) +{ + struct cpu *c = &per_cpu(cpu_devices, cpu); + + register_cpu(c, cpu); + device_create_file(&c->dev, &dev_attr_physical_id); + return 0; +} + +int unregister_ppc_cpu(int cpu) +{ + device_remove_file(&per_cpu(cpu_devices, cpu).dev, + &dev_attr_physical_id); + unregister_cpu(container_of(get_cpu_device(cpu), + struct cpu, dev)); + return 0; +} + static int __init topology_init(void) { int cpu, r; @@ -1044,11 +1073,8 @@ static int __init topology_init(void) if (ppc_md.cpu_die) c->hotpluggable = 1; - if (cpu_online(cpu) || c->hotpluggable) { - register_cpu(c, cpu); - - device_create_file(&c->dev, &dev_attr_physical_id); - } + if (cpu_online(cpu) || c->hotpluggable) + register_ppc_cpu(cpu); } r = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/topology:online", register_cpu_online, unregister_cpu_online); diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index 6ef77ca..f361fc8 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -37,6 +37,7 @@ #include <asm/xive.h> #include <asm/plpar_wrappers.h> #include <asm/topology.h> +#include <asm/setup.h> #include "pseries.h" #include "offline_states.h" @@ -367,6 +368,11 @@ static int dlpar_online_cpu(struct device_node *dn) cpu_maps_update_done(); timed_topology_update(1); find_and_online_cpu_nid(cpu); + /* protect against the offline's failure, + * then re-online + */ + if (cpudev_is_dummy(cpu)) + register_ppc_cpu(cpu); rc = device_online(get_cpu_device(cpu)); if (rc) goto out; @@ -530,8 +536,12 @@ static int dlpar_offline_cpu(struct device_node *dn) if (get_hard_smp_processor_id(cpu) != thread) continue; - if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE) + if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE) { + cpu_maps_update_done(); + unregister_ppc_cpu(cpu); + cpu_maps_update_begin(); break; + } if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) { set_preferred_offline_state(cpu, @@ -541,6 +551,7 @@ static int dlpar_offline_cpu(struct device_node *dn) rc = device_offline(get_cpu_device(cpu)); if (rc) goto out; + unregister_ppc_cpu(cpu); cpu_maps_update_begin(); break; @@ -554,6 +565,9 @@ static int dlpar_offline_cpu(struct device_node *dn) BUG_ON(plpar_hcall_norets(H_PROD, thread) != H_SUCCESS); __cpu_die(cpu); + cpu_maps_update_done(); + unregister_ppc_cpu(cpu); + cpu_maps_update_begin(); break; } if (cpu == num_possible_cpus())
Technically speaking, echo 1/0 > cpuX/online is only a subset of cpu hotplug/unplug, i.e. add/remove. The latter one includes the physical adding/removing of a cpu device. Some user space tools such as kexec-tools resort to the event add/remove to automatically rebuild dtb. If the dtb is not rebuilt correctly, we may hang on 2nd kernel due to lack the info of boot-cpu-hwid in dtb. The steps to trigger the bug: (suppose 8 threads/core) drmgr -c cpu -r -q 1 systemctl restart kdump.service drmgr -c cpu -a -q 1 taskset -c 11 sh -c "echo c > /proc/sysrq-trigger" Then, failure info: [ 205.299528] SysRq : Trigger a crash [ 205.299551] Unable to handle kernel paging request for data at address 0x00000000 [ 205.299558] Faulting instruction address: 0xc0000000006001a0 [ 205.299564] Oops: Kernel access of bad area, sig: 11 [#1] [ 205.299569] SMP NR_CPUS=2048 NUMA pSeries [ 205.299575] Modules linked in: macsec sctp_diag sctp tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag ip6t_rpfilter ipt_REJECT nf_reject_ipv4 ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter xfs libcrc32c sg pseries_rng binfmt_misc ip_tables ext4 mbcache jbd2 sd_mod crc_t10dif crct10dif_generic crct10dif_common ibmvscsi scsi_transport_srp ibmveth scsi_tgt dm_mirror dm_region_hash dm_log dm_mod [ 205.299658] CPU: 11 PID: 2521 Comm: bash Not tainted 3.10.0-799.el7.ppc64le #1 [ 205.299664] task: c00000017bcd15e0 ti: c00000014f410000 task.ti: c00000014f410000 [ 205.299670] NIP: c0000000006001a0 LR: c000000000600ddc CTR: c000000000600180 [ 205.299676] REGS: c00000014f413a70 TRAP: 0300 Not tainted (3.10.0-799.el7.ppc64le) [ 205.299681] MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 28222822 XER: 00000001 [ 205.299696] CFAR: c000000000009368 DAR: 0000000000000000 DSISR: 42000000 SOFTE: 1 GPR00: c000000000600dbc c00000014f413cf0 c000000001263200 0000000000000063 GPR04: c0000000019ca818 c0000000019db5f8 00000000000000c2 c00000000140aa30 GPR08: 0000000000000007 0000000000000001 0000000000000000 c00000000140fc60 GPR12: c000000000600180 c000000007b36300 0000000010139e58 0000000040000000 GPR16: 000000001013b5d0 0000000000000000 00000000101306fc 0000000010139de4 GPR20: 0000000010139de8 0000000010093150 0000000000000000 0000000000000000 GPR24: 000000001013b5e0 00000000100fa0e8 0000000000000007 c0000000011af1c8 GPR28: 0000000000000063 c0000000011af588 c000000001179ba8 0000000000000002 [ 205.299770] NIP [c0000000006001a0] sysrq_handle_crash+0x20/0x30 [ 205.299776] LR [c000000000600ddc] write_sysrq_trigger+0x10c/0x230 [ 205.299781] Call Trace: [ 205.299786] [c00000014f413cf0] [c000000000600dbc] write_sysrq_trigger+0xec/0x230 (unreliable) [ 205.299794] [c00000014f413d90] [c0000000003eb2c4] proc_reg_write+0x84/0x120 [ 205.299801] [c00000014f413dd0] [c000000000330a80] SyS_write+0x150/0x400 [ 205.299808] [c00000014f413e30] [c00000000000a184] system_call+0x38/0xb4 [ 205.299813] Instruction dump: [ 205.299816] 409effb8 7fc3f378 4bfff381 4bffffac 3c4c00c6 38423080 3d42fff1 394a6930 [ 205.299827] 39200001 912a0000 7c0004ac 39400000 <992a0000> 4e800020 60000000 60420000 [ 205.299838] ---[ end trace f590a5dbd3f63aab ]--- [ 205.301812] [ 205.301829] Sending IPI to other CPUs [ 205.302846] IPI complete I'm in purgatory -- > hang up here This patch uses the interface register_/unregister_cpu to fix the problem. Test the compatibility with ppc64_cpu on a powerKVM guest, with the following topo: Thread(s) per core: 8 Core(s) per socket: 2 Socket(s): 2 NUMA node(s): 1 and the following instructions: ppc64_cpu --smt=off drmgr -c cpu -r 1 drmgr -c cpu -a 1 ppc64_cpu --smt=on or drmgr -c cpu -r 1 ppc64_cpu --smt=off drmgr -c cpu -a 1 ppc64_cpu --smt=on Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> Cc: linux-pm@vger.kernel.org Signed-off-by: Pingfan Liu <kernelfans@gmail.com> --- v2 -> v3 create sysfs file "dev_attr_physical_id" before cpu online callbacks, hence it can work with ppc64_cpu --- arch/powerpc/include/asm/setup.h | 4 +++ arch/powerpc/include/asm/smp.h | 1 + arch/powerpc/kernel/sysfs.c | 38 +++++++++++++++++++++++----- arch/powerpc/platforms/pseries/hotplug-cpu.c | 16 +++++++++++- 4 files changed, 52 insertions(+), 7 deletions(-)