Messages in this thread | | | From | "Stephen C. Tweedie" <> | Date | Mon, 11 Oct 1999 16:05:31 +0100 (BST) | Subject | Re: locking question: do_mmap(), do_munmap() |
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Hi,
On Sat, 9 Oct 1999 18:01:27 +0200 (CEST), Andrea Arcangeli <andrea@suse.de> said:
> On Sat, 9 Oct 1999, Alexander Viro wrote: >> do_munmap() doesn't need the big lock. do_mmap() callers should grab
> Look the swapout path. Without the big kernel lock you'll free vmas under > swap_out().
Yes. The swapout code relies on the big lock to freeze the vma, and on the page_table_lock to protect the ptes, so that it can avoid worrying about the mm_sem at all.
If munmap ever drops vmas without the big lock, the swapper _will_ break. Making this into a per-mm lock would not be hard, btw.
--Stephen
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