Re: [RFC PATCH v2 15/21] loop: use aio to perform io on the underlying file

[Jeff Moyer]

Dave Kleikamp <dave.kleikamp@xxxxxxxxxx> writes:

> On 04/20/2012 09:48 AM, Maxim V. Patlasov wrote:
>> On 03/30/2012 07:43 PM, Dave Kleikamp wrote:
>>> From: Zach Brown<zab@xxxxxxxxx>
>>>
>>> This uses the new kernel aio interface to process loopback IO by
>>> submitting concurrent direct aio.  Previously loop's IO was serialized
>>> by synchronous processing in a thread.
>>>
>> 
>> The patch ignores REQ_FLUSH bit of bi_rw. Is it simply overlook?
>
> Good question. Since the loop device is sending only direct IO requests,
> it shouldn't be necessary to explicitly flush page cache, but REQ_FLUSH

REQ_FLUSH isn't about the page cache, it's about flushing the volatile
disk write cache.  You need to handle that.

Cheers,
Jeff
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/