Messages in this thread | | | Date | Thu, 02 Jan 2003 22:46:43 -0800 | From | David Brownell <> | Subject | Re: [PATCH] generic device DMA (dma_pool update) |
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Adam J. Richter wrote: > In practice, I think that if we just added one, maybe two, > URB's by default for every endpoint when a device is added, that > that would be enough to guarantee that would reduce the number of > drivers that needed to reserve more URB's than that to few or none.
I seem to recall someone posted a patch to make non-iso URB allocation use a mempool.
>>Hmm, I was unaware that anyone expected GFP_KERNEL (or rather, >>__GFP_WAIT) to guarantee that memory was always returned. It's >>not called __GFP_NEVERFAIL, after all. > > > mempool_alloc does. That's the point of it. You calculate > how many objects you need in order to guarantee no deadlocks and > reserve that number in advance (the initial reservation can fail).
To rephrase that so it illustrates my point: the whole reason to use mempool is to try adding __GFP_NEVERFAIL when __GFP_WAIT is given ... because __GFP_WAIT doesn't otherwise mean NEVERFAIL.
- Dave
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