Re: [PATCH] mm: add config for readahead window

[Andrew Morton]

On Fri, 16 Mar 2018 21:51:48 +0000 Wei Wang <wei.vince.wang@xxxxxxxxx> wrote:

> On Fri, Mar 16, 2018, 14:33 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> 
> > On Fri, 16 Mar 2018 11:25:08 -0700 Wei Wang <wvw@xxxxxxxxxx> wrote:
> >
> > > Change VM_MAX_READAHEAD value from the default 128KB to a configurable
> > > value. This will allow the readahead window to grow to a maximum size
> > > bigger than 128KB during boot, which could benefit to sequential read
> > > throughput and thus boot performance.
> >
> > You can presently run ioctl(BLKRASET) against the block device?
> >
> 
> Yeah we are doing tuning in userland after init. But this is something we
> thought could help in very early stage.
> 

"thought" and "could" are rather weak!  Some impressive performance
numbers for real-world setups would help such a patch along.