Re: [RFC][PATCH v3 2/6] mm, directio: fix fork vs direct-io race (read(2) side IOW gup(write) side)

[Jeff Moyer]

Andrea Arcangeli <aarcange@xxxxxxxxxx> writes:

> On Tue, Apr 14, 2009 at 12:45:41PM -0400, Jeff Moyer wrote:
>> So, if you're continuously submitting async read I/O, you will starve
>> out the fork() call indefinitely.  I agree that you want to allow
>
> IIRC rwsem good enough to stop the down_read when a down_write is
> blocked. Otherwise page fault flood in threads would also starve any
> mmap or similar call. Still with this approach fork will start to hang

Really?  I don't actually see that in the code, have I missed it?

Cheers,
Jeff
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