On 07/16/2010 10:29 PM, H. Peter Anvin wrote:
quoted text
> On 07/16/2010 11:32 AM, Avi Kivity wrote:
>    
>> How long would vmalloc_sync_all take with a few thousand mm_struct take?
>>
>> We share the pmds, yes?  So it's a few thousand memory accesses.  The
>> direct impact is probably negligible, compared to actually loading the
>> module from disk.  All we need is to make sure the locking doesn't slow
>> down unrelated stuff.
>>
>>      
> It's not the memory accesses, it's the need to synchronize all the CPUs.
>    

I'm missing something.  Why do we need to sync all cpus?  the 
vmalloc_sync_all() I'm reading doesn't.

Even if we do an on_each_cpu() somewhere, it isn't the end of the world.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

--
unsubscribe notice
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/