From d899bf7b55f503ba7d3d07ed27c3a37e270fa7db Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Tue, 22 Sep 2009 16:45:40 -0700 Subject: [PATCH] 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//{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//task//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//{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//{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 Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Alexey Dobriyan Cc: "Eric W. Biederman" Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/filesystems/proc.txt | 5 ++- fs/exec.c | 2 + fs/proc/array.c | 85 +++++++++++++++++++++++++++++++++++++- fs/proc/task_mmu.c | 19 +++++++++ include/linux/sched.h | 1 + kernel/fork.c | 2 + mm/Makefile | 4 +- 7 files changed, 114 insertions(+), 4 deletions(-) diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 75988ba26a51..b5aee7838a00 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -176,6 +176,7 @@ read the file /proc/PID/status: CapBnd: ffffffffffffffff voluntary_ctxt_switches: 0 nonvoluntary_ctxt_switches: 1 + Stack usage: 12 kB This shows you nearly the same information you would get if you viewed it with the ps command. In fact, ps uses the proc file system to obtain its @@ -229,6 +230,7 @@ Table 1-2: Contents of the statm files (as of 2.6.30-rc7) Mems_allowed_list Same as previous, but in "list format" voluntary_ctxt_switches number of voluntary context switches nonvoluntary_ctxt_switches number of non voluntary context switches + Stack usage: stack usage high water mark (round up to page size) .............................................................................. Table 1-3: Contents of the statm files (as of 2.6.8-rc3) @@ -307,7 +309,7 @@ address perms offset dev inode pathname 08049000-0804a000 rw-p 00001000 03:00 8312 /opt/test 0804a000-0806b000 rw-p 00000000 00:00 0 [heap] a7cb1000-a7cb2000 ---p 00000000 00:00 0 -a7cb2000-a7eb2000 rw-p 00000000 00:00 0 +a7cb2000-a7eb2000 rw-p 00000000 00:00 0 [threadstack:001ff4b4] a7eb2000-a7eb3000 ---p 00000000 00:00 0 a7eb3000-a7ed5000 rw-p 00000000 00:00 0 a7ed5000-a8008000 r-xp 00000000 03:00 4222 /lib/libc.so.6 @@ -343,6 +345,7 @@ is not associated with a file: [stack] = the stack of the main process [vdso] = the "virtual dynamic shared object", the kernel system call handler + [threadstack:xxxxxxxx] = the stack of the thread, xxxxxxxx is the stack size or if empty, the mapping is anonymous. diff --git a/fs/exec.c b/fs/exec.c index 69bb9d899791..5c833c18d0d4 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1357,6 +1357,8 @@ int do_execve(char * filename, if (retval < 0) goto out; + current->stack_start = current->mm->start_stack; + /* execve succeeded */ current->fs->in_exec = 0; current->in_execve = 0; diff --git a/fs/proc/array.c b/fs/proc/array.c index 725a650bbbb8..0c6bc602e6c4 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -82,6 +82,7 @@ #include #include #include +#include #include #include @@ -321,6 +322,87 @@ static inline void task_context_switch_counts(struct seq_file *m, p->nivcsw); } +struct stack_stats { + struct vm_area_struct *vma; + unsigned long startpage; + unsigned long usage; +}; + +static int stack_usage_pte_range(pmd_t *pmd, unsigned long addr, + unsigned long end, struct mm_walk *walk) +{ + struct stack_stats *ss = walk->private; + struct vm_area_struct *vma = ss->vma; + pte_t *pte, ptent; + spinlock_t *ptl; + int ret = 0; + + pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + for (; addr != end; pte++, addr += PAGE_SIZE) { + ptent = *pte; + +#ifdef CONFIG_STACK_GROWSUP + if (pte_present(ptent) || is_swap_pte(ptent)) + ss->usage = addr - ss->startpage + PAGE_SIZE; +#else + if (pte_present(ptent) || is_swap_pte(ptent)) { + ss->usage = ss->startpage - addr + PAGE_SIZE; + pte++; + ret = 1; + break; + } +#endif + } + pte_unmap_unlock(pte - 1, ptl); + cond_resched(); + return ret; +} + +static inline unsigned long get_stack_usage_in_bytes(struct vm_area_struct *vma, + struct task_struct *task) +{ + struct stack_stats ss; + struct mm_walk stack_walk = { + .pmd_entry = stack_usage_pte_range, + .mm = vma->vm_mm, + .private = &ss, + }; + + if (!vma->vm_mm || is_vm_hugetlb_page(vma)) + return 0; + + ss.vma = vma; + ss.startpage = task->stack_start & PAGE_MASK; + ss.usage = 0; + +#ifdef CONFIG_STACK_GROWSUP + walk_page_range(KSTK_ESP(task) & PAGE_MASK, vma->vm_end, + &stack_walk); +#else + walk_page_range(vma->vm_start, (KSTK_ESP(task) & PAGE_MASK) + PAGE_SIZE, + &stack_walk); +#endif + return ss.usage; +} + +static inline void task_show_stack_usage(struct seq_file *m, + struct task_struct *task) +{ + struct vm_area_struct *vma; + struct mm_struct *mm = get_task_mm(task); + + if (mm) { + down_read(&mm->mmap_sem); + vma = find_vma(mm, task->stack_start); + if (vma) + seq_printf(m, "Stack usage:\t%lu kB\n", + get_stack_usage_in_bytes(vma, task) >> 10); + + up_read(&mm->mmap_sem); + mmput(mm); + } +} + int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { @@ -340,6 +422,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, task_show_regs(m, task); #endif task_context_switch_counts(m, task); + task_show_stack_usage(m, task); return 0; } @@ -481,7 +564,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, rsslim, mm ? mm->start_code : 0, mm ? mm->end_code : 0, - (permitted && mm) ? mm->start_stack : 0, + (permitted) ? task->stack_start : 0, esp, eip, /* The signal information here is obsolete. diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 366b1017a4f1..2a1bef9203c6 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -243,6 +243,25 @@ static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma) } else if (vma->vm_start <= mm->start_stack && vma->vm_end >= mm->start_stack) { name = "[stack]"; + } else { + unsigned long stack_start; + struct proc_maps_private *pmp; + + pmp = m->private; + stack_start = pmp->task->stack_start; + + if (vma->vm_start <= stack_start && + vma->vm_end >= stack_start) { + pad_len_spaces(m, len); + seq_printf(m, + "[threadstack:%08lx]", +#ifdef CONFIG_STACK_GROWSUP + vma->vm_end - stack_start +#else + stack_start - vma->vm_start +#endif + ); + } } } else { name = "[vdso]"; diff --git a/include/linux/sched.h b/include/linux/sched.h index 6448bbc6406b..3cbc6c0be666 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1529,6 +1529,7 @@ struct task_struct { /* bitmask of trace recursion */ unsigned long trace_recursion; #endif /* CONFIG_TRACING */ + unsigned long stack_start; }; /* Future-safe accessor for struct task_struct's cpus_allowed. */ diff --git a/kernel/fork.c b/kernel/fork.c index 7cf45812ce84..8f45b0ebdda7 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1095,6 +1095,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, p->bts = NULL; + p->stack_start = stack_start; + /* Perform scheduler related setup. Assign this task to a CPU. */ sched_fork(p, clone_flags); diff --git a/mm/Makefile b/mm/Makefile index 728a9fde49d1..88193d73cd1a 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -11,10 +11,10 @@ obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \ maccess.o page_alloc.o page-writeback.o \ readahead.o swap.o truncate.o vmscan.o shmem.o \ prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \ - page_isolation.o mm_init.o mmu_context.o $(mmu-y) + page_isolation.o mm_init.o mmu_context.o \ + pagewalk.o $(mmu-y) obj-y += init-mm.o -obj-$(CONFIG_PROC_PAGE_MONITOR) += pagewalk.o obj-$(CONFIG_BOUNCE) += bounce.o obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o thrash.o obj-$(CONFIG_HAS_DMA) += dmapool.o -- 2.11.4.GIT