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. Thanks, Naoya Horiguchi --- Previous versions: v1: https://lore.kernel.org/linux-mm/1541746035-13408-1-git-send-email-n-horiguchi@xxxxxxxxxxxxx/ v2: https://lore.kernel.org/linux-mm/20191017142123.24245-1-osalvador@xxxxxxx/ v3: https://lore.kernel.org/linux-mm/20200624150137.7052-1-nao.horiguchi@xxxxxxxxx/ v4: https://lore.kernel.org/linux-mm/20200716123810.25292-1-osalvador@xxxxxxx/ --- 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(-)
