Re: [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline

From: kbuild test robot
Date: Thu Feb 09 2017 - 02:30:41 EST

Hi Hoeun,

[auto build test ERROR on next-20170208]
[also build test ERROR on v4.10-rc7]
[cannot apply to linus/master linux/master v4.9-rc8 v4.9-rc7 v4.9-rc6]
[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/Hoeun-Ryu/fork-free-vmapped-stacks-in-cache-when-cpus-are-offline/20170209-124143
config: parisc-c3000_defconfig (attached as .config)
compiler: hppa-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=parisc

All error/warnings (new ones prefixed by >>):

kernel/fork.c: In function 'free_vm_stack_cache':
>> kernel/fork.c:177:18: error: 'NR_CACHED_STACKS' undeclared (first use in this function)
for (i = 0; i < NR_CACHED_STACKS; i++) {
^~~~~~~~~~~~~~~~
kernel/fork.c:177:18: note: each undeclared identifier is reported only once for each function it appears in
In file included from include/asm-generic/percpu.h:6:0,
from ./arch/parisc/include/generated/asm/percpu.h:1,
from arch/parisc/include/asm/processor.h:19,
from arch/parisc/include/asm/thread_info.h:7,
from include/linux/thread_info.h:25,
from include/asm-generic/preempt.h:4,
from ./arch/parisc/include/generated/asm/preempt.h:1,
from include/linux/preempt.h:59,
from include/linux/spinlock.h:50,
from include/linux/mmzone.h:7,
from include/linux/gfp.h:5,
from include/linux/slab.h:14,
from kernel/fork.c:14:
>> kernel/fork.c:178:46: error: 'cached_stacks' undeclared (first use in this function)
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^
include/linux/percpu-defs.h:305:9: note: in definition of macro '__pcpu_size_call_return'
typeof(variable) pscr_ret__; \
^~~~~~~~
>> kernel/fork.c:178:32: note: in expansion of macro 'this_cpu_read'
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^~~~~~~~~~~~~
>> include/linux/percpu-defs.h:304:1: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
({ \
^
include/linux/percpu-defs.h:494:29: note: in expansion of macro '__pcpu_size_call_return'
#define this_cpu_read(pcp) __pcpu_size_call_return(this_cpu_read_, pcp)
^~~~~~~~~~~~~~~~~~~~~~~
>> kernel/fork.c:178:32: note: in expansion of macro 'this_cpu_read'
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^~~~~~~~~~~~~
At top level:
kernel/fork.c:173:12: warning: 'free_vm_stack_cache' defined but not used [-Wunused-function]
static int free_vm_stack_cache(unsigned int cpu)
^~~~~~~~~~~~~~~~~~~

vim +/NR_CACHED_STACKS +177 kernel/fork.c

8 * 'fork.c' contains the help-routines for the 'fork' system call
9 * (see also entry.S and others).
10 * Fork is rather simple, once you get the hang of it, but the memory
11 * management can be a bitch. See 'mm/memory.c': 'copy_page_range()'
12 */
13
> 14 #include <linux/slab.h>
15 #include <linux/init.h>
16 #include <linux/unistd.h>
17 #include <linux/module.h>
18 #include <linux/vmalloc.h>
19 #include <linux/completion.h>
20 #include <linux/personality.h>
21 #include <linux/mempolicy.h>
22 #include <linux/sem.h>
23 #include <linux/file.h>
24 #include <linux/fdtable.h>
25 #include <linux/iocontext.h>
26 #include <linux/key.h>
27 #include <linux/binfmts.h>
28 #include <linux/mman.h>
29 #include <linux/mmu_notifier.h>
30 #include <linux/fs.h>
31 #include <linux/mm.h>
32 #include <linux/vmacache.h>
33 #include <linux/nsproxy.h>
34 #include <linux/capability.h>
35 #include <linux/cpu.h>
36 #include <linux/cgroup.h>
37 #include <linux/security.h>
38 #include <linux/hugetlb.h>
39 #include <linux/seccomp.h>
40 #include <linux/swap.h>
41 #include <linux/syscalls.h>
42 #include <linux/jiffies.h>
43 #include <linux/futex.h>
44 #include <linux/compat.h>
45 #include <linux/kthread.h>
46 #include <linux/task_io_accounting_ops.h>
47 #include <linux/rcupdate.h>
48 #include <linux/ptrace.h>
49 #include <linux/mount.h>
50 #include <linux/audit.h>
51 #include <linux/memcontrol.h>
52 #include <linux/ftrace.h>
53 #include <linux/proc_fs.h>
54 #include <linux/profile.h>
55 #include <linux/rmap.h>
56 #include <linux/ksm.h>
57 #include <linux/acct.h>
58 #include <linux/userfaultfd_k.h>
59 #include <linux/tsacct_kern.h>
60 #include <linux/cn_proc.h>
61 #include <linux/freezer.h>
62 #include <linux/delayacct.h>
63 #include <linux/taskstats_kern.h>
64 #include <linux/random.h>
65 #include <linux/tty.h>
66 #include <linux/blkdev.h>
67 #include <linux/fs_struct.h>
68 #include <linux/magic.h>
69 #include <linux/perf_event.h>
70 #include <linux/posix-timers.h>
71 #include <linux/user-return-notifier.h>
72 #include <linux/oom.h>
73 #include <linux/khugepaged.h>
74 #include <linux/signalfd.h>
75 #include <linux/uprobes.h>
76 #include <linux/aio.h>
77 #include <linux/compiler.h>
78 #include <linux/sysctl.h>
79 #include <linux/kcov.h>
80
81 #include <asm/pgtable.h>
82 #include <asm/pgalloc.h>
83 #include <linux/uaccess.h>
84 #include <asm/mmu_context.h>
85 #include <asm/cacheflush.h>
86 #include <asm/tlbflush.h>
87
88 #include <trace/events/sched.h>
89
90 #define CREATE_TRACE_POINTS
91 #include <trace/events/task.h>
92
93 /*
94 * Minimum number of threads to boot the kernel
95 */
96 #define MIN_THREADS 20
97
98 /*
99 * Maximum number of threads
100 */
101 #define MAX_THREADS FUTEX_TID_MASK
102
103 /*
104 * Protected counters by write_lock_irq(&tasklist_lock)
105 */
106 unsigned long total_forks; /* Handle normal Linux uptimes. */
107 int nr_threads; /* The idle threads do not count.. */
108
109 int max_threads; /* tunable limit on nr_threads */
110
111 DEFINE_PER_CPU(unsigned long, process_counts) = 0;
112
113 __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */
114
115 #ifdef CONFIG_PROVE_RCU
116 int lockdep_tasklist_lock_is_held(void)
117 {
118 return lockdep_is_held(&tasklist_lock);
119 }
120 EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);
121 #endif /* #ifdef CONFIG_PROVE_RCU */
122
123 int nr_processes(void)
124 {
125 int cpu;
126 int total = 0;
127
128 for_each_possible_cpu(cpu)
129 total += per_cpu(process_counts, cpu);
130
131 return total;
132 }
133
134 void __weak arch_release_task_struct(struct task_struct *tsk)
135 {
136 }
137
138 #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
139 static struct kmem_cache *task_struct_cachep;
140
141 static inline struct task_struct *alloc_task_struct_node(int node)
142 {
143 return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
144 }
145
146 static inline void free_task_struct(struct task_struct *tsk)
147 {
148 kmem_cache_free(task_struct_cachep, tsk);
149 }
150 #endif
151
152 void __weak arch_release_thread_stack(unsigned long *stack)
153 {
154 }
155
156 #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR
157
158 /*
159 * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
160 * kmemcache based allocator.
161 */
162 # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)
163
164 #ifdef CONFIG_VMAP_STACK
165 /*
166 * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
167 * flush. Try to minimize the number of calls by caching stacks.
168 */
169 #define NR_CACHED_STACKS 2
170 static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
171 #endif
172
173 static int free_vm_stack_cache(unsigned int cpu)
174 {
175 int i;
176
> 177 for (i = 0; i < NR_CACHED_STACKS; i++) {
> 178 struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
179 if (!vm_stack)
180 continue;
181

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