Bottom halves being disabled

Linh Dang linhd at nortelnetworks.com
Wed Aug 25 08:46:32 EDT 2004


David Woodhouse <dwmw2 at infradead.org> wrote:

> On Wed, 2004-08-25 at 06:48 -0400, Linh Dang wrote:
>> reduce latency with preemptable kernel. I've tried that. In my test
>> I hammered jffs2 pretty hard (for typical flash usage, no kernel
>> compilation here) and everything still seemed ok.
>
> Show numbers.

On my card (AMD Am29LV640 NOR flash), preemption was often disabled
for 450usecs in cfi_cmdset_002.c's do_read_onechip().

using semaphore instead of spin_lock, preemption would NOT be disabled
at all!

Btw, JFFS2 is great!

-- 
Linh Dang




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