Re: cdrom changes in test13-pre2 slow down cdrom access by 70%

[David Mansfield <lkml@dm.ultramaster.com>]

Jens Axboe wrote:
> 
> In principle it looks ok, but after some time we are bound to fail 8
> frame allocations anyway and this patch won't help. For the modular
> case, preallocation of a bigger chunk at init time is no good either.
> Builtin would be fine of course. This almost screams sg to me :-)
> 

Nonetheless, with your first patch and my patch, the system starts off
using the old method of trying to allocate 8 frames buffer (which is
essential for performance) and falls back to the current (as of
test13-pre2) way in low/fragmented memory situations. To me, that's
better than either the previous or the current method, with the slight
increased cost of the failed kmalloc every time in the low/fragmented
memory case.  BTW, have you gotten reports of that kmalloc failing for
people?  I've been ripping audio with every kernel since pre4 and have
never had a failure.  Granted, I put 'workstation' loads on my machine,
but I run some benchmarks from time-to-time, put memory pressure on
etc.  (H*ll, just netscape alone is memory pressure enough :-).

I just don't want to have to patch every kernel I run from here to
eternity.  Call me selfish.

David

-- 
David Mansfield                                           (718) 963-2020
david@ultramaster.com
Ultramaster Group, LLC                               www.ultramaster.com
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