Messages in this thread | | | Date | Wed, 30 Jun 2010 13:57:28 +0300 | From | Boaz Harrosh <> | Subject | Re: [PATCH 1/2] block: fix leaks associated with discard request payload |
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On 06/30/2010 01:41 PM, Christoph Hellwig wrote: > On Wed, Jun 30, 2010 at 01:25:01PM +0300, Boaz Harrosh wrote: >> OK, Thanks, I see. Is it one of these operations, (like we have in OSD) where >> the CDB information spills into the payload? like the scatter-gather and extent >> lists and such. > > For UNMAP the payload is a list of block number / length pairs, while > the CDB itself doesn't contain any information like that. It's a rather > awkward command. >
How big can that be? could we, maybe, use the sense_buffer, properly allocated already?
>> Do we actually use a WRITE_SAME which is not zero? for what use? > > The kernel doesn't issue any WRITE SAME without the unmap bit set.
So if the unmap bit is set then the page can just be zero, right?
I still think a static zero-page is a worth while optimization. And block-drivers can take care with special needs with a private mem_pool or something. For the discard-type user and generic block layer the page is just an implementation specific residue, No?
But don't mind me, I'm just babbling. Not that I'll do anything about it. Boaz
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