Messages in this thread | | | Date | Mon, 22 Nov 2010 21:57:46 -0800 | From | Andrew Morton <> | Subject | Re: [RFC] mlock: release mmap_sem every 256 faulted pages |
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On Mon, 22 Nov 2010 21:00:52 -0800 Michel Lespinasse <walken@google.com> wrote:
> Hi, > > I'd like to sollicit comments on this proposal: > > Currently mlock() holds mmap_sem in exclusive mode while the pages get > faulted in. In the case of a large mlock, this can potentially take a > very long time.
A more compelling description of why this problem needs addressing would help things along.
> + /* > + * Limit batch size to 256 pages in order to reduce > + * mmap_sem hold time. > + */ > + nfault = nstart + 256 * PAGE_SIZE;
It would be nicer if there was an rwsem API to ask if anyone is currently blocked in down_read() or down_write(). That wouldn't be too hard to do. It wouldn't detect people polling down_read_trylock() or down_write_trylock() though.
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