lkml.org 
[lkml]   [2004]   [Apr]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [ANNOUNCE][RELEASE]: megaraid unified driver version 2.20.0.B 1
Mukker, Atul wrote:
>>megaraid_clib.c:
>> - why do you need the scb pool managment code at all? You
>>can dynamically
>> allocate scbs in ->queuecommand
>
> Will do. Please see the follow up question below

If there is a static maximum of scbs for megaraid hardware, dynamically
allocating scbs in ->queuecommand is a waste of time.

In my drivers, I pre-allocate driver-specific per-request structures --
just like the SCSI layer does ;-)

If you follow this -- faster -- approach, make sure you don't waste a
lot of memory with pre-allocated scb's you'll rarely use.


>> - can you explain the need for all the mraid_pci_blk_pool?
>>I.e. why the
>> generic dma pool routines don't work for megaraid
>
> We did not want to use pci_alloc_consistent because it would give one page
> even if we need 16 bytes (and we need a lot of these). Also, the
> pci_poo_create and pci_pool_alloc would fail on some setups - maybe because
> the driver requires lots of small chunks of DMAable buffers. So we decided
> to write wrapper functions over pci_alloc_consistent..

Would prefer to identify the root cause of pci_pool_xxx failure, since
that is the proper API to use.

Jeff



-
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 14:02    [W:0.023 / U:2.720 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site