lkml.org 
[lkml]   [2003]   [Jan]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] generic device DMA (dma_pool update)
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


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

\
 
 \ /
  Last update: 2005-03-22 13:32    [W:0.054 / U:1.600 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site