Laundry

[Doug Hardie]

> On 26 July 2020, at 13:31, Konstantin Belousov <kostikbel at gmail.com> wrote:
> 
> On Sun, Jul 26, 2020 at 01:11:33PM -0700, Doug Hardie wrote:
>> I have a production system (12.1-RELEASE-p6) that is showing around 1 GB of Laundry pages.  There are over 6 Gb Inact and 1 Gb free.  I can understand why the system would want to not prioritize laundering those pages as there is plenty of available pages.  However, does that mean that I have about 1 GB of updated files that have not been written back to disk?  If so, then there is a significant issue with power failures and loss of data.
>> 
> Laundry keeps both file-backed (named) pages and swap-backed (anonymous)
> pages. Most likely it means that you have 1G of anonymous dirty
> mappings, for instance programs data/bss and malloced.

I don't believe there are very man anonymous pages, but there are lots of named pages.  If those are dirty, does that mean they have not yet been written back to disk?  The loss of those would be quite detrimental if not written back to disk.

-- Doug