Re: [PATCH] mm : sync ra->ra_pages with bdi->ra_pages

From: Andrew Morton
Date: Sat Aug 15 2020 - 18:12:21 EST


On Fri, 14 Aug 2020 13:10:34 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Fri, 14 Aug 2020 17:03:44 +0800 Zhaoyang Huang <huangzhaoyang@xxxxxxxxx> wrote:
>
> > Some system(like android) will turbo read during startup via expanding the
> > readahead window and then set it back to normal(128kb as usual). However, some
> > files in the system process context will keep to be opened since it is opened
> > up and has no chance to sync with the updated value as it is almost impossible
> > to change the files attached to the inode(processes are unaware of these things)
>
> How about making VM_READAHEAD_PAGES a variable?

Or make it settable in Kconfig?