This is the follow-up of: https://lkml.org/lkml/2019/9/10/711 We can get rid of the memory isolate notifier by switching to balloon compaction in powerpc's CMM (Collaborative Memory Management). The memory isolate notifier was only necessary to allow to offline memory blocks that contain inflated/"loaned" pages - which also possible when the inflated pages are movable (via balloon compaction). Having movable pages implies that memory will also no longer get fragmented when CMM is active. While I do have access to a LPAR, it does not have CMM active and I have np clue how to enable it. Instead, I implemented a simple simulation mode. I did some tests and the whole infrastructure, including page migration, seems to work fine (e.g., I can still offline memory blocks that contain inflated pages). Of course, I cannot tell if HW will like the changes, especially: 1. I now use page_to_phys() to come up with the addresses to report to the hypervisor. Hope that's correct. 2. When migrating a page, I first inflate/"loan" the new page and then deflate the old page. I have no idea if HW accepts to set pages loaned if it didn't request a loan. I assume it does. 3. We might now inflate/deflate pages in parallel (of course, not the same page). I have no idea if HW likes that. It would be good if somebody could either point me at the spec of the hypervisor interface or verify directly. Also, it would be good if somebody could test with actual HW that has this feature. Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Alexey Kardashevskiy <aik@xxxxxxxxx> Cc: Allison Randal <allison@xxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx> Cc: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx> Cc: Arun KS <arunks@xxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Christian Brauner <christian@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: "Enrico Weigelt, metux IT consult" <info@xxxxxxxxx> Cc: Gao Xiang <xiang@xxxxxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Greg Hackmann <ghackmann@xxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Cc: "Oliver O'Halloran" <oohall@xxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Cc: Pingfan Liu <kernelfans@xxxxxxxxx> Cc: Qian Cai <cai@xxxxxx> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> Cc: Richard Fontana <rfontana@xxxxxxxxxx> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> Cc: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Todd Kjos <tkjos@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> David Hildenbrand (12): powerpc/pseries: CMM: Implement release() function for sysfs device powerpc/pseries: CMM: Report errors when registering notifiers fails powerpc/pseries: CMM: Cleanup rc handling in cmm_init() powerpc/pseries: CMM: Drop page array powerpc/pseries: CMM: Use adjust_managed_page_count() insted of totalram_pages_* powerpc/pseries: CMM: Rip out memory isolate notifier powerpc/pseries: CMM: Convert loaned_pages to an atomic_long_t powerpc/pseries: CMM: Implement balloon compaction powerpc/pseries: CMM: Switch to balloon_page_alloc() powerpc/pseries: CMM: Simulation mode mm: remove the memory isolate notifier mm: remove "count" parameter from has_unmovable_pages() arch/powerpc/platforms/pseries/Kconfig | 1 + arch/powerpc/platforms/pseries/cmm.c | 430 +++++++++++-------------- drivers/base/memory.c | 19 -- include/linux/memory.h | 27 -- include/linux/page-isolation.h | 4 +- include/uapi/linux/magic.h | 1 + mm/memory_hotplug.c | 2 +- mm/page_alloc.c | 21 +- mm/page_isolation.c | 27 +- 9 files changed, 204 insertions(+), 328 deletions(-) -- 2.21.0
