Re: [PATCHSET v3.1 0/7] data integrity: Stabilize pages during writeback for various fses

[OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>]

Jan Kara <jack@xxxxxxx> writes:

>> Did you already consider, to copy only if page was writeback (like
>> copy-on-write)? I.e. if page is on I/O, copy, then switch the page for
>> writing new data.
>   Yes, that was considered as well. We'd have to essentially migrate the
> page that is under writeback and should be written to. You are going to pay
> the cost of page allocation, copy, increased memory & cache pressure.
> Depending on your backing storage and workload this may or may not be better
> than waiting for IO...

Maybe possible, but you really think on usual case just blocking is
better?

Thanks.
-- 
OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
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