Re: [GIT PULL] block bits for 3.1-rc

[Jens Axboe]

On 2011-08-20 19:41, Christoph Hellwig wrote:
> On Fri, Aug 19, 2011 at 03:16:40PM +0200, Jens Axboe wrote:
>> - Revert of the CFQ meta data special treatment patch, it's been shown
>>   to regress a kernel build workload by about 10%. More investigation
>>   is needed, for 3.1 lets just back it out.
> 
> Sorry, but you can't simply do that without any coordination.  We have
> added that marker to xfs now that the stupid special casing stopped,
> and turning it back on will cause us massive slowdows.  Next time
> please better coordinate this with its users.  In fact I have never
> seen this patch or a discussion on any mailinglist.

The discussion was on lkml, as Mike points out. But yes, short time to
react. Since I can't easily cater to both cases right now, how about we
add a temporary second meta flag that is only used for tracing?

        REQ_META        = (__REQ_META | __REQ_META_TRACE),
        RET_META_TRACE  = __REQ_META_TRACE,

You get the idea. Not super pretty, but it should solve the immediate
issue.

-- 
Jens Axboe

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