Messages in this thread | | | Date | Thu, 14 Jun 2012 11:02:02 +0200 | From | Paolo Bonzini <> | Subject | Re: [PATCH 2/2] msync: start async writeout when MS_ASYNC |
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Il 13/06/2012 23:29, Andrew Morton ha scritto: > > If the application does not want to start I/O, it can simply call msync > > with flags equal to MS_INVALIDATE. This one remains a no-op, as it should > > be on a reasonable implementation. > > Means that people will find that their msync(MS_ASYNC) call will newly > start IO. This may well be undesirable for some.
If they knew it was a no-op, and relying on it, they might as well not have called it at all and save a syscall.
> Also, it hardwires into the kernel behaviour which userspace itself > could have initiated, with sync_file_range(). ie: reduced flexibility.
No, it hardwires into the kernel behaviour which is mentioned in the spec. Strictly speaking it is correct that an asynchronous operation is never done (the two are indistinguishable), but still this patch improves the fidelity to the specification and in a portable manner.
Paolo
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