Re: write drop behind effect on active scanning

[Marcelo Tosatti]

On Wed, 23 May 2001, Daniel Phillips wrote:

> On Wednesday 23 May 2001 09:33, Marcelo Tosatti wrote:
> > Hi,
> >
> > I just noticed a "bad" effect of write drop behind yesterday during
> > some tests.
> >
> > The problem is that we deactivate written pages, thus making the
> > inactive list become pretty big (full of unfreeable pages) under
> > write intensive IO workloads.
> >
> > So what happens is that we don't do _any_ aging on the active list,
> > and in the meantime the inactive list (which should have "easily"
> > freeable pages) is full of locked pages.
> >
> > I'm going to fix this one by replacing "deactivate_page(page)" to
> > "ClearPageReferenced(page)" in generic_file_write(). This way the
> > written pages are aged faster but we avoid the bad effect just
> > described.
> >
> > Any comments on the fix ?
> 
>   page->age = 0 ?

That would make any full scan through the active list move all dropped
pages from generic_file_write() to the inactive list.