linux-kernel – / proc / sys / fs / file-max的缺省值

/* And dynamically-tunable limits and defaults: */
struct files_stat_struct {
  unsigned long nr_files;   /* read only */
  unsigned long nr_free_files;  /* read only */
  unsigned long max_files;    /* tunable THIS IS OUR VALUE */
};

现在在./fs/file_table.c中,files_stat_struct开始使用：

struct files_stat_struct files_stat = {
  .max_files = NR_FILE /* This constant is 8192 */
};

现在在前一个文件中“./fs/file_table.c”将具有将成为真正工作的功能

void __init files_init(unsigned long mempages)
{
  unsigned long n;

  filp_cachep = kmem_cache_create("filp",sizeof(struct filE),SLAB_HWCACHE_ALIGN | SLAB_PANIC,null);

  /*
   * One file with associated inode and dcache is very roughly 1K.
   * Per default don't use more than 10% of our memory for files. 
   */

  n = (mempages * (PAGE_SIZE / 1024)) / 10;
  files_stat.max_files = max_t(unsigned long,n,NR_FILE);
  files_defer_init();
  lg_lock_init(files_lglock);
  percpu_counter_init(&nr_files,0);
}

从我在files_init中看到并查看宏max_t,如果文件的10％内存大于8192,将使用这些值,除非8192.

在内核开始执行时使用files_init,当调用kmem_cache_create创建常规文件slab缓存时,需要查看标志SLAB_PANIC.

现在你需要看看./kernel/sysctl.c

{
    .procname = "file-max",.data   = &files_stat.max_files,.maxlen   = sizeof(files_stat.max_files),.mode   = 0644,.proc_handler = proc_doulongvec_minmax,},

file-max是内存的10％,如果你的系统有不同的内存大小,我认为这是正常的.