Re: [PATCH] drm/i915: Use hash tables for the command parser

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 05/08/2014 12:44 PM, Damien Lespiau wrote:
> On Thu, May 08, 2014 at 10:56:05AM +0100, Tvrtko Ursulin wrote:
>>
>> Hi Brad,
>>
>> On 04/28/2014 04:22 PM, bradley.d.volkin@intel.com wrote:
>> [snip]
>>> -	BUG_ON(!validate_cmds_sorted(ring));
>>> +	BUG_ON(!validate_cmds_sorted(ring, cmd_tables, cmd_table_count));
>>>   	BUG_ON(!validate_regs_sorted(ring));
>>> +
>>> +	BUG_ON(init_hash_table(ring, cmd_tables, cmd_table_count));
>>
>> Is a BUG_ON a bit harsh since the above fails only on ENOMEM condition?
>>
>> If the concern is not allowing any command execution if parser setup
>> has failed, it would be nicer to the system as whole to just keep
>> rejecting everything, but let the rest of the kernel live to enable
>> debug or whatever?
>
> Those number_of_cmds allocations are a bit awkward though, couldn't we
> just embed the hlist_node into the desciptor struct?

Until Brad comes online, I think that is because command descriptors to 
hash table entries are not 1-to-1.

Tvrtko