On Thu, Mar 05, 2015 at 01:55:15PM +0100, Jerome Marchand wrote: > On 03/04/2015 05:32 PM, Kirill A. Shutemov wrote: > > Hello everybody, > > > > It's bug-fix update of my thp refcounting work. > > > > The goal of patchset is to make refcounting on THP pages cheaper with > > simpler semantics and allow the same THP compound page to be mapped with > > PMD and PTEs. This is required to get reasonable THP-pagecache > > implementation. > > > > With the new refcounting design it's much easier to protect against > > split_huge_page(): simple reference on a page will make you the deal. > > It makes gup_fast() implementation simpler and doesn't require > > special-case in futex code to handle tail THP pages. > > > > It should improve THP utilization over the system since splitting THP in > > one process doesn't necessary lead to splitting the page in all other > > processes have the page mapped. > > > [...] > > I believe all known bugs have been fixed, but I'm sure Sasha will bring more > > reports. > > > > The patchset also available on git: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/kas/linux.git thp/refcounting/v4 > > > > Hi Kirill, > > I ran some ltp tests and it triggered two bugs: Okay. The root of both is change in page_mapped(). I'll think how to fix this. -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>