linux - How do I increase the /proc/pid/cmdline 4096 byte limit?

Question

For my Java apps with very long classpaths, I cannot see the main class specified near the end of the arg list when using ps. I think this stems from my Ubuntu system's size limit on /proc/pid/cmdline. How can I increase this limit?

question from:https://stackoverflow.com/questions/199130/how-do-i-increase-the-proc-pid-cmdline-4096-byte-limit

Answer 1

You can't change this dynamically, the limit is hard-coded in the kernel to PAGE_SIZE in fs/proc/base.c:

 274        int res = 0;
 275        unsigned int len;
 276        struct mm_struct *mm = get_task_mm(task);
 277        if (!mm)
 278                goto out;
 279        if (!mm->arg_end)
 280                goto out_mm;    /* Shh! No looking before we're done */
 281
 282        len = mm->arg_end - mm->arg_start;
 283 
 284        if (len > PAGE_SIZE)
 285                len = PAGE_SIZE;
 286 
 287        res = access_process_vm(task, mm->arg_start, buffer, len, 0);