Re: [libvirt] libxl: calculating free pages in libvirt

On gio, 2013-06-06 at 14:59 +0100, Ian Campbell wrote: > On Thu, 2013-06-06 at 15:53 +0200, Dario Faggioli wrote: > >> Hi Jim, >> >> As I told you in Dublin, I'm looking into libvirt a bit, with the main >> purpose of implementing the NUMA interface for the libxl driver. >> >> While at it I noticed that libxlNodeGetFreeMemory() uses the value >> contained in phy_info.free_pages to check how many pages of free memory >> we have. >> >> However, starting from (Xen's git) commit bec8f17e, the number of free >> pages should be computed like this: >> >> (phy_info.free_pages - phy_info.outstanding_pages) >> >> to take the memory claiming mechanism introduced by Oracle properly into >> account. >> > This only really matters if libvirt wants to coexist on a host with > toolstacks which use claim, otherwise outstanding pages will never be > non-zero. I don't know if coexistence is a goal or not. > > Sure, all this is important only if having it is important/interesting... Jim?