linux – 文件描述符的数量：/ proc / sys / fs / file-nr和/ proc / $pid / fd之间有什么不同？

   @H_502_17@/proc/[pid]/task (since Linux 2.6.0-test6)
          This is a directory that contains one subdirectory for each
          thread in the process.  The name of each subdirectory is the
          numerical thread ID (@H_502_17@[tid]) of the thread (see 07001).
          Within each of these subdirectories,there is a set of files
          with the same names and contents as under the @H_502_17@/proc/[pid]
          directories.  For attributes that are shared by all threads,the contents for each of the files under the @H_502_17@task/[tid]
          subdirectories will be the same as in the corresponding file
          in the parent @H_502_17@/proc/[pid] directory (e.g.,in a multithreaded
          process,all of the @H_502_17@task/[tid]/cwd files will have the same
          value as the @H_502_17@/proc/[pid]/cwd file in the parent directory,since all of the threads in a process share a working
          directory).  For attributes that are disTinct for each thread,the corresponding files under @H_502_17@task/[tid] may have different
          values (e.g.,varIoUs fields in each of the @H_502_17@task/[tid]/status
          files may be different for each thread).

          In a multithreaded process,the contents of the
          @H_502_17@/proc/[pid]/task directory are not available if the main
          thread has already terminated (typically by calling
          07002).

我会通过运行来计算打开文件描述符的数量：

ps -eL | awk 'NR > 1 { print $1,$2 }' | \
while read x; do \
    find /proc/${x% *}/task/${x#* }/fd/ -type l; \
done | wc -l

结果是17270.

让我们看看自启动以来分配了多少文件描述符：

cat /proc/sys/fs/file-nr 
11616   0   398855

为什么/ proc / [pid] / task / [tid] / fd中的文件描述符数量超过/ proc / sys / fs / file-nr中分配的文件句柄数？我想它们是由分叉的子进程创建的：

man fork：

man pthreads：