On Mon, Sep 21, 2009 at 10:10:17AM -0400, Mike Frysinger wrote:
> it works without having to copy & paste the same exact structures over
> and over. a suggestion as how to do it cleanly without bloating the
> code is certainly welcome. it doesnt really matter that it's on the
> stack as the usage is small and d_path() is given the size of the
> buffer, so it isnt going to overflow.
Umm... Surely, you can put a CPU number + one bit into PDE->data? As in
proc_create_data("icplb", ....., (void *)(cpu * 2))
proc_create_data("dcplb", ....., (void *)(cpu * 2 + 1))
and
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
unsigned long n = (unsigned long) pde->data;
...
cpu = n / 2;
is_D = n & 1;
> > ??For another... locking in that loop
> > over processes and VMAs of each looks very suspicios, while we are at it.
>
> we've reviewed it several times and exercised it in multiple ways. so
> unless you have a real idea of something being wrong, the code has
> been vetted heavily.
write_lock_irq tasklist_lock
loop over processes
get_task_mm [now VM is pinned down, but not locked]
walk the VMA list without any locking
Something on another CPU (you have SMP systems, judging by the previously
discussed code, right?) does munmap().
Boom.
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
