Messages in this thread | | | Date | Thu, 03 Dec 2009 07:16:07 +0900 | From | Tejun Heo <> | Subject | Re: problems in linux-next (Was: Re: linux-next: Tree for December 1) |
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On 12/02/2009 11:55 PM, Christoph Lameter wrote: > On Wed, 2 Dec 2009, Tejun Heo wrote: > >> This isn't usual alignment. struct work_struct has one data fields >> which is overloaded for two purposes. Lower few bits are used to >> carry flags while upper bits are used to point to sruct >> cpu_workqueue_struct. So, the number of available bits for flags are >> determined by the alignment of cpu_workqueue_struct. Memory usage for > > The default mininum slab alignment in UP is 8 bytes which means you can > use 3 bits. And as far as I can see only the lower two bits are used. You > still have one bit leftover. (current upstream that is did not check if > you modified it).
For colored workqueue flushing, it ends up using more than three bits. I haven't decided it fully yet but total of six or seven depending on how many colors are used. So, we need forced alignment anyway.
Thanks.
-- tejun
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