On Fri, Jul 31, 2020 at 12:20:56PM +0000, [email protected] wrote: > This patchset is the latest version of soft offline rework patchset > targetted for v5.9. > > Main focus of this series is to stabilize soft offline. Historically soft > offlined pages have suffered from racy conditions because PageHWPoison is > used to a little too aggressively, which (directly or indirectly) invades > other mm code which cares little about hwpoison. This results in unexpected > behavior or kernel panic, which is very far from soft offline's "do not > disturb userspace or other kernel component" policy. > > Main point of this change set is to contain target page "via buddy allocator", > where we first free the target page as we do for normal pages, and remove > from buddy only when we confirm that it reaches free list. There is surely > race window of page allocation, but that's fine because someone really want > that page and the page is still working, so soft offline can happily give up. > > v4 from Oscar tries to handle the race around reallocation, but that part > seems still work in progress, so I decide to separate it for changes into > v5.9. Thank you for your contribution, Oscar. > > The issue reported by Qian Cai is fixed by patch 16/16. > > This patchset is based on v5.8-rc7-mmotm-2020-07-27-18-18, but I applied > this series after reverting previous version. > Maybe https://github.com/Naoya-Horiguchi/linux/commits/soft-offline-rework.v5 > shows what I did more precisely. > > Any other comment/suggestion/help would be appreciated.
There is another issue with this patchset (with and without the patch [1]). [1] https://lore.kernel.org/lkml/[email protected]/ Arm64 using 512M-size hugepages starts to fail allocations prematurely. # ./random 1 - start: migrate_huge_offline - use NUMA nodes 0,1. - mmap and free 2147483648 bytes hugepages on node 0 - mmap and free 2147483648 bytes hugepages on node 1 madvise: Cannot allocate memory [ 284.388061][ T3706] soft offline: 0x956000: hugepage isolation failed: 0, page count 2, type 17ffff80001000e (referenced|uptodate|dirty|head) [ 284.400777][ T3706] Soft offlining pfn 0x8e000 at process virtual address 0xffff80000000 [ 284.893412][ T3706] Soft offlining pfn 0x8a000 at process virtual address 0xffff60000000 [ 284.901539][ T3706] soft offline: 0x8a000: hugepage isolation failed: 0, page count 2, type 7ffff80001000e (referenced|uptodate|dirty|head) [ 284.914129][ T3706] Soft offlining pfn 0x8c000 at process virtual address 0xffff80000000 [ 285.433497][ T3706] Soft offlining pfn 0x88000 at process virtual address 0xffff60000000 [ 285.720377][ T3706] Soft offlining pfn 0x8a000 at process virtual address 0xffff80000000 [ 286.281620][ T3706] Soft offlining pfn 0xa000 at process virtual address 0xffff60000000 [ 286.290065][ T3706] soft offline: 0xa000: hugepage migration failed -12, type 7ffff80001000e (referenced|uptodate|dirty|head) Reverting this patchset and its dependency patchset [2] (reverting the dependency alone did not help) fixed it, # ./random 1 - start: migrate_huge_offline - use NUMA nodes 0,1. - mmap and free 2147483648 bytes hugepages on node 0 - mmap and free 2147483648 bytes hugepages on node 1 - pass: mmap_offline_node_huge [2] https://lore.kernel.org/linux-mm/[email protected]/ > > Thanks, > Naoya Horiguchi > --- > Previous versions: > v1: > https://lore.kernel.org/linux-mm/[email protected]/ > v2: > https://lore.kernel.org/linux-mm/[email protected]/ > v3: > https://lore.kernel.org/linux-mm/[email protected]/ > v4: > https://lore.kernel.org/linux-mm/[email protected]/ > --- > Summary: > > Naoya Horiguchi (8): > mm,hwpoison: cleanup unused PageHuge() check > mm, hwpoison: remove recalculating hpage > mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED > mm,hwpoison-inject: don't pin for hwpoison_filter > mm,hwpoison: remove MF_COUNT_INCREASED > mm,hwpoison: remove flag argument from soft offline functions > mm,hwpoison: introduce MF_MSG_UNSPLIT_THP > mm,hwpoison: double-check page count in __get_any_page() > > Oscar Salvador (8): > mm,madvise: Refactor madvise_inject_error > mm,hwpoison: Un-export get_hwpoison_page and make it static > mm,hwpoison: Kill put_hwpoison_page > mm,hwpoison: Unify THP handling for hard and soft offline > mm,hwpoison: Rework soft offline for free pages > mm,hwpoison: Rework soft offline for in-use pages > mm,hwpoison: Refactor soft_offline_huge_page and __soft_offline_page > mm,hwpoison: Return 0 if the page is already poisoned in soft-offline > > drivers/base/memory.c | 2 +- > include/linux/mm.h | 12 +- > include/linux/page-flags.h | 6 +- > include/ras/ras_event.h | 3 + > mm/hwpoison-inject.c | 18 +-- > mm/madvise.c | 39 +++--- > mm/memory-failure.c | 334 > ++++++++++++++++++++------------------------- > mm/migrate.c | 11 +- > mm/page_alloc.c | 60 ++++++-- > 9 files changed, 233 insertions(+), 252 deletions(-)
