On Thu 26-01-17 22:23:18, Ted Tso wrote:

quoted

And aio_write() isn't non-blocking for O_DIRECT already because .... oh,
it doesn't even try.  Is there something intrinsically hard about async
O_DIRECT writes, or is it just that no-one has written acceptable code
yet?

AIO/DIO writes can indeed be non-blocking, if the file system doesn't
need to do any metadata operations.  So if the file is preallocated,
you should be able to issue an async DIO write without losing the CPU.

Well, there are couple ifs though. You can still block on locks, memory
allocation, or IO request allocation...

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR

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