On Mon, Jun 14, 2021 at 07:05:47PM -0700, akpm@xxxxxxxxxxxxxxxxxxxx wrote: > > The patch titled > Subject: mm: mark idle page tracking as BROKEN > has been added to the -mm tree. Its filename is > mm-mark-idle-page-tracking-as-broken.patch > > This patch should soon appear at > https://ozlabs.org/~akpm/mmots/broken-out/mm-mark-idle-page-tracking-as-broken.patch > and later at > https://ozlabs.org/~akpm/mmotm/broken-out/mm-mark-idle-page-tracking-as-broken.patch > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** > > The -mm tree is included into linux-next and is updated > there every 3-4 working days > > ------------------------------------------------------ > From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> > Subject: mm: mark idle page tracking as BROKEN > > In discussion with other MM developers around how idle page tracking > should be fixed for transparent huge pages, several expressed the opinion > that it should be removed as it is inefficient at accomplishing the job > that it is supposed to, and we have better mechanisms (eg uffd) for > accomplishing the same goals these days. I didn't follow the aforementioned discussion, so it would be nice to have a little bit more detailed explanation on both points raised here (issues with THP and innefficiency). There are some Red Hat customers and partners that do rely on the feature, thus the interest. Thanks. > Mark the feature as BROKEN for now and we can remove it entirely in a few > months if nobody complains. It is not enabled by Android, ChromeOS, > Debian, Fedora or SUSE. Red Hat enabled it with RHEL-8.1 and UEK followed > suit, but I have been unable to find why RHEL enabled it. minor nit on the RHEL mention: CONFIG_IDLE_PAGE_TRACKING is enabled since 8.0 for RHEL-8, and 7.7 for RHEL-7. Cheers, -- Rafael
