Re: [PATCH] fs: optimise generic_write_check_limits()

[Pavel Begunkov]

On 8/6/21 2:28 PM, Matthew Wilcox wrote:
> On Fri, Aug 06, 2021 at 12:22:10PM +0100, Pavel Begunkov wrote:
>> Even though ->s_maxbytes is used by generic_write_check_limits() only in
>> case of O_LARGEFILE, the value is loaded unconditionally, which is heavy
>> and takes 4 indirect loads. Optimise it by not touching ->s_maxbytes,
>> if it's not going to be used.
> 
> Is this "optimisation" actually worth anything?  Look at how
> force_o_largefile() is used.  I would suggest that on the vast majority
> of machines, O_LARGEFILE is always set.

Makes sense to leave it alone then, thanks

-- 
Pavel Begunkov