procfs: provide stack information for threads
A patch to give a better overview of the userland application stack usage, especially for embedded linux. Currently you are only able to dump the main process/thread stack usage which is showed in /proc/pid/status by the "VmStk" Value. But you get no information about the consumed stack memory of the the threads. There is an enhancement in the /proc/<pid>/{task/*,}/*maps and which marks the vm mapping where the thread stack pointer reside with "[thread stack xxxxxxxx]". xxxxxxxx is the maximum size of stack. This is a value information, because libpthread doesn't set the start of the stack to the top of the mapped area, depending of the pthread usage. A sample output of /proc/<pid>/task/<tid>/maps looks like: 08048000-08049000 r-xp 00000000 03:00 8312 /opt/z 08049000-0804a000 rw-p 00001000 03:00 8312 /opt/z 0804a000-0806b000 rw-p 00000000 00:00 0 [heap] a7d12000-a7d13000 ---p 00000000 00:00 0 a7d13000-a7f13000 rw-p 00000000 00:00 0 [thread stack: 001ff4b4] a7f13000-a7f14000 ---p 00000000 00:00 0 a7f14000-a7f36000 rw-p 00000000 00:00 0 a7f36000-a8069000 r-xp 00000000 03:00 4222 /lib/libc.so.6 a8069000-a806b000 r--p 00133000 03:00 4222 /lib/libc.so.6 a806b000-a806c000 rw-p 00135000 03:00 4222 /lib/libc.so.6 a806c000-a806f000 rw-p 00000000 00:00 0 a806f000-a8083000 r-xp 00000000 03:00 14462 /lib/libpthread.so.0 a8083000-a8084000 r--p 00013000 03:00 14462 /lib/libpthread.so.0 a8084000-a8085000 rw-p 00014000 03:00 14462 /lib/libpthread.so.0 a8085000-a8088000 rw-p 00000000 00:00 0 a8088000-a80a4000 r-xp 00000000 03:00 8317 /lib/ld-linux.so.2 a80a4000-a80a5000 r--p 0001b000 03:00 8317 /lib/ld-linux.so.2 a80a5000-a80a6000 rw-p 0001c000 03:00 8317 /lib/ld-linux.so.2 afaf5000-afb0a000 rw-p 00000000 00:00 0 [stack] ffffe000-fffff000 r-xp 00000000 00:00 0 [vdso] Also there is a new entry "stack usage" in /proc/<pid>/{task/*,}/status which will you give the current stack usage in kb. A sample output of /proc/self/status looks like: Name: cat State: R (running) Tgid: 507 Pid: 507 . . . CapBnd: fffffffffffffeff voluntary_ctxt_switches: 0 nonvoluntary_ctxt_switches: 0 Stack usage: 12 kB I also fixed stack base address in /proc/<pid>/{task/*,}/stat to the base address of the associated thread stack and not the one of the main process. This makes more sense. [akpm@linux-foundation.org: fs/proc/array.c now needs walk_page_range()] Signed-off-by: Stefani Seibold <stefani@seibold.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
cba8aafe1e
commit
d899bf7b55
7 changed files with 114 additions and 4 deletions
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@ -176,6 +176,7 @@ read the file /proc/PID/status:
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CapBnd: ffffffffffffffff
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voluntary_ctxt_switches: 0
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nonvoluntary_ctxt_switches: 1
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Stack usage: 12 kB
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This shows you nearly the same information you would get if you viewed it with
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the ps command. In fact, ps uses the proc file system to obtain its
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@ -229,6 +230,7 @@ Table 1-2: Contents of the statm files (as of 2.6.30-rc7)
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Mems_allowed_list Same as previous, but in "list format"
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voluntary_ctxt_switches number of voluntary context switches
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nonvoluntary_ctxt_switches number of non voluntary context switches
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Stack usage: stack usage high water mark (round up to page size)
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..............................................................................
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Table 1-3: Contents of the statm files (as of 2.6.8-rc3)
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@ -307,7 +309,7 @@ address perms offset dev inode pathname
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08049000-0804a000 rw-p 00001000 03:00 8312 /opt/test
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0804a000-0806b000 rw-p 00000000 00:00 0 [heap]
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a7cb1000-a7cb2000 ---p 00000000 00:00 0
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a7cb2000-a7eb2000 rw-p 00000000 00:00 0
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a7cb2000-a7eb2000 rw-p 00000000 00:00 0 [threadstack:001ff4b4]
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a7eb2000-a7eb3000 ---p 00000000 00:00 0
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a7eb3000-a7ed5000 rw-p 00000000 00:00 0
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a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6
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@ -343,6 +345,7 @@ is not associated with a file:
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[stack] = the stack of the main process
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[vdso] = the "virtual dynamic shared object",
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the kernel system call handler
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[threadstack:xxxxxxxx] = the stack of the thread, xxxxxxxx is the stack size
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or if empty, the mapping is anonymous.
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@ -1357,6 +1357,8 @@ int do_execve(char * filename,
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if (retval < 0)
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goto out;
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current->stack_start = current->mm->start_stack;
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/* execve succeeded */
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current->fs->in_exec = 0;
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current->in_execve = 0;
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@ -82,6 +82,7 @@
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#include <linux/pid_namespace.h>
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#include <linux/ptrace.h>
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#include <linux/tracehook.h>
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#include <linux/swapops.h>
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#include <asm/pgtable.h>
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#include <asm/processor.h>
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@ -321,6 +322,87 @@ static inline void task_context_switch_counts(struct seq_file *m,
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p->nivcsw);
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}
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struct stack_stats {
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struct vm_area_struct *vma;
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unsigned long startpage;
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unsigned long usage;
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};
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static int stack_usage_pte_range(pmd_t *pmd, unsigned long addr,
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unsigned long end, struct mm_walk *walk)
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{
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struct stack_stats *ss = walk->private;
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struct vm_area_struct *vma = ss->vma;
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pte_t *pte, ptent;
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spinlock_t *ptl;
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int ret = 0;
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pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
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for (; addr != end; pte++, addr += PAGE_SIZE) {
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ptent = *pte;
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#ifdef CONFIG_STACK_GROWSUP
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if (pte_present(ptent) || is_swap_pte(ptent))
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ss->usage = addr - ss->startpage + PAGE_SIZE;
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#else
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if (pte_present(ptent) || is_swap_pte(ptent)) {
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ss->usage = ss->startpage - addr + PAGE_SIZE;
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pte++;
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ret = 1;
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break;
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}
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#endif
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}
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pte_unmap_unlock(pte - 1, ptl);
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cond_resched();
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return ret;
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}
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static inline unsigned long get_stack_usage_in_bytes(struct vm_area_struct *vma,
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struct task_struct *task)
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{
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struct stack_stats ss;
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struct mm_walk stack_walk = {
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.pmd_entry = stack_usage_pte_range,
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.mm = vma->vm_mm,
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.private = &ss,
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};
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if (!vma->vm_mm || is_vm_hugetlb_page(vma))
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return 0;
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ss.vma = vma;
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ss.startpage = task->stack_start & PAGE_MASK;
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ss.usage = 0;
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#ifdef CONFIG_STACK_GROWSUP
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walk_page_range(KSTK_ESP(task) & PAGE_MASK, vma->vm_end,
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&stack_walk);
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#else
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walk_page_range(vma->vm_start, (KSTK_ESP(task) & PAGE_MASK) + PAGE_SIZE,
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&stack_walk);
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#endif
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return ss.usage;
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}
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static inline void task_show_stack_usage(struct seq_file *m,
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struct task_struct *task)
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{
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struct vm_area_struct *vma;
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struct mm_struct *mm = get_task_mm(task);
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if (mm) {
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, task->stack_start);
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if (vma)
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seq_printf(m, "Stack usage:\t%lu kB\n",
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get_stack_usage_in_bytes(vma, task) >> 10);
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up_read(&mm->mmap_sem);
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mmput(mm);
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}
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}
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int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
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struct pid *pid, struct task_struct *task)
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{
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@ -340,6 +422,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
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task_show_regs(m, task);
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#endif
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task_context_switch_counts(m, task);
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task_show_stack_usage(m, task);
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return 0;
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}
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@ -481,7 +564,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
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rsslim,
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mm ? mm->start_code : 0,
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mm ? mm->end_code : 0,
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(permitted && mm) ? mm->start_stack : 0,
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(permitted) ? task->stack_start : 0,
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esp,
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eip,
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/* The signal information here is obsolete.
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@ -243,6 +243,25 @@ static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
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} else if (vma->vm_start <= mm->start_stack &&
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vma->vm_end >= mm->start_stack) {
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name = "[stack]";
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} else {
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unsigned long stack_start;
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struct proc_maps_private *pmp;
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pmp = m->private;
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stack_start = pmp->task->stack_start;
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if (vma->vm_start <= stack_start &&
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vma->vm_end >= stack_start) {
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pad_len_spaces(m, len);
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seq_printf(m,
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"[threadstack:%08lx]",
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#ifdef CONFIG_STACK_GROWSUP
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vma->vm_end - stack_start
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#else
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stack_start - vma->vm_start
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#endif
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);
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}
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}
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} else {
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name = "[vdso]";
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@ -1529,6 +1529,7 @@ struct task_struct {
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/* bitmask of trace recursion */
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unsigned long trace_recursion;
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#endif /* CONFIG_TRACING */
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unsigned long stack_start;
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};
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/* Future-safe accessor for struct task_struct's cpus_allowed. */
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@ -1095,6 +1095,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
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p->bts = NULL;
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p->stack_start = stack_start;
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/* Perform scheduler related setup. Assign this task to a CPU. */
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sched_fork(p, clone_flags);
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@ -11,10 +11,10 @@ obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
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maccess.o page_alloc.o page-writeback.o \
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readahead.o swap.o truncate.o vmscan.o shmem.o \
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prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
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page_isolation.o mm_init.o mmu_context.o $(mmu-y)
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page_isolation.o mm_init.o mmu_context.o \
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pagewalk.o $(mmu-y)
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obj-y += init-mm.o
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obj-$(CONFIG_PROC_PAGE_MONITOR) += pagewalk.o
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obj-$(CONFIG_BOUNCE) += bounce.o
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obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o thrash.o
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obj-$(CONFIG_HAS_DMA) += dmapool.o
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