Messages in this thread | | | Date | Sun, 19 Jun 2005 13:23:33 -0700 | From | Chris Wright <> | Subject | Re: [PATCH] Bug #3054 madvise(MADV_WILLNEED,...) fix for exceeding rlimit rss |
| |
* Matt Keenan (matthew.keenan@ntlworld.com) wrote: > --- linux-2.6.11.7/mm/madvise.c 2005-04-12 15:58:30.000000000 +0100 > +++ linux/mm/madvise.c 2005-06-19 17:20:56.000000000 +0100 > @@ -61,6 +61,7 @@ static long madvise_willneed(struct vm_a > unsigned long start, unsigned long end) > { > struct file *file = vma->vm_file; > + struct task_struct *tsk = current;
Looks like you've got some tab/whitespace damage going on here.
> if (!file) > return -EBADF; > @@ -70,6 +71,28 @@ static long madvise_willneed(struct vm_a > end = vma->vm_end; > end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; > > + /* > + * This code below checks to see if mapping the requested > + * readahead would make the task's rss exceed the task's > + * rlimit rss. > + * > + * This doesn't account for pages that may already be mapped > + * due to readahead, but since this is merely a hint to the > + * kernel no harm should be done, it won't unmap anything > + * already mapped if it fails. N.B. This won't affect the > + * kernel's internal automatic readahead which doesn't check > + * (or honour) rlimit rss. > + */ > + > + spin_lock(&tsk->mm->page_table_lock); > + if (((max_sane_readahead(end-start) << PAGE_SHIFT) + > + tsk->mm->_rss) > tsk->signal->rlim[RLIMIT_RSS].rlim_cur)
I doubt this one would overflow, but we recenly made changes in similar tests to use page count rather than byte count. I belive this should use get_mm_counter(). Isn't _rss counting pages rather than bytes, so I think the math is off here. Something like:
if ((max_sane_readahead(end - start) + get_mm_counter(tsk->mm, rss)) > tsk->signal->rlim[RLIMIT_RSS].rlim_cur >> PAGE_SHIFT)
thanks, -chris - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |