The patch titled memcg: memory hotplug fix for notifier callback has been removed from the -mm tree. Its filename was memcg-memory-hotplug-fix-for-notifier-callback.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: memcg: memory hotplug fix for notifier callback From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Fixes for memcg/memory hotplug. While memory hotplug allocate/free memmap, page_cgroup doesn't free page_cgroup at OFFLINE when page_cgroup is allocated via bootomem. (Because freeing bootmem requires special care.) Then, if page_cgroup is allocated by bootmem and memmap is freed/allocated by memory hotplug, page_cgroup->page == page is no longer true. But current MEM_ONLINE handler doesn't check it and update page_cgroup->page if it's not necessary to allocate page_cgroup. (This was not found because memmap is not freed if SPARSEMEM_VMEMMAP is y.) And I noticed that MEM_ONLINE can be called against "part of section". So, freeing page_cgroup at CANCEL_ONLINE will cause trouble. (freeing used page_cgroup) Don't rollback at CANCEL. One more, current memory hotplug notifier is stopped by slub because it sets NOTIFY_STOP_MASK to return vaule. So, page_cgroup's callback never be called. (low priority than slub now.) I think this slub's behavior is not intentional(BUG). and fixes it. Another way to be considered about page_cgroup allocation: - free page_cgroup at OFFLINE even if it's from bootmem and remove specieal handler. But it requires more changes. Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12041 Signed-off-by: KAMEZAWA Hiruyoki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx> Cc: Balbir Singh <balbir@xxxxxxxxxx> Cc: Pavel Emelyanov <xemul@xxxxxxxxxx> Tested-by: Badari Pulavarty <pbadari@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_cgroup.c | 43 +++++++++++++++++++++++++++++-------------- mm/slub.c | 6 ++++-- 2 files changed, 33 insertions(+), 16 deletions(-) diff -puN mm/page_cgroup.c~memcg-memory-hotplug-fix-for-notifier-callback mm/page_cgroup.c --- a/mm/page_cgroup.c~memcg-memory-hotplug-fix-for-notifier-callback +++ a/mm/page_cgroup.c @@ -107,19 +107,29 @@ int __init_refok init_section_page_cgrou section = __pfn_to_section(pfn); - if (section->page_cgroup) - return 0; - - nid = page_to_nid(pfn_to_page(pfn)); - - table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION; - if (slab_is_available()) { - base = kmalloc_node(table_size, GFP_KERNEL, nid); - if (!base) - base = vmalloc_node(table_size, nid); - } else { - base = __alloc_bootmem_node_nopanic(NODE_DATA(nid), table_size, + if (!section->page_cgroup) { + nid = page_to_nid(pfn_to_page(pfn)); + table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION; + if (slab_is_available()) { + base = kmalloc_node(table_size, GFP_KERNEL, nid); + if (!base) + base = vmalloc_node(table_size, nid); + } else { + base = __alloc_bootmem_node_nopanic(NODE_DATA(nid), + table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS)); + } + } else { + /* + * We don't have to allocate page_cgroup again, but + * address of memmap may be changed. So, we have to initialize + * again. + */ + base = section->page_cgroup + pfn; + table_size = 0; + /* check address of memmap is changed or not. */ + if (base->page == pfn_to_page(pfn)) + return 0; } if (!base) { @@ -208,18 +218,23 @@ static int __meminit page_cgroup_callbac ret = online_page_cgroup(mn->start_pfn, mn->nr_pages, mn->status_change_nid); break; - case MEM_CANCEL_ONLINE: case MEM_OFFLINE: offline_page_cgroup(mn->start_pfn, mn->nr_pages, mn->status_change_nid); break; + case MEM_CANCEL_ONLINE: case MEM_GOING_OFFLINE: break; case MEM_ONLINE: case MEM_CANCEL_OFFLINE: break; } - ret = notifier_from_errno(ret); + + if (ret) + ret = notifier_from_errno(ret); + else + ret = NOTIFY_OK; + return ret; } diff -puN mm/slub.c~memcg-memory-hotplug-fix-for-notifier-callback mm/slub.c --- a/mm/slub.c~memcg-memory-hotplug-fix-for-notifier-callback +++ a/mm/slub.c @@ -2931,8 +2931,10 @@ static int slab_memory_callback(struct n case MEM_CANCEL_OFFLINE: break; } - - ret = notifier_from_errno(ret); + if (ret) + ret = notifier_from_errno(ret); + else + ret = NOTIFY_OK; return ret; } _ Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are vmscan-evict-streaming-io-first.patch mm-gup-persist-for-write-permission.patch mm-wp-lock-page-before-deciding-cow.patch mm-reuse_swap_page-replaces-can_share_swap_page.patch mm-try_to_free_swap-replaces-remove_exclusive_swap_page.patch mm-try_to_unuse-check-removing-right-swap.patch mm-remove-try_to_munlock-from-vmscan.patch mm-remove-gfp_mask-from-add_to_swap.patch mm-add-add_to_swap-stub.patch mm-optimize-get_scan_ratio-for-no-swap.patch memcg-reclaim-shouldnt-change-zone-recent_rotated-statistics.patch swapfile-swapon-needs-larger-size-type.patch swapfile-remove-swp_active-mask.patch swapfile-remove-surplus-whitespace.patch swapfile-remove-v0-swap-space-message.patch swapfile-rearrange-scan-and-swap_info.patch swapfile-swapon-use-discard-trim.patch swapfile-swap-allocation-use-discard.patch swapfile-swapon-randomize-if-nonrot.patch swapfile-swap-allocation-cycle-if-nonrot.patch cgroups-make-cgroup-config-a-submenu.patch cgroups-documentation-updates.patch cgroups-remove-some-redundant-null-checks.patch ns_cgroup-remove-unused-spinlock.patch memcg-fix-a-typo-in-kconfig.patch cgroups-add-lock-for-child-cgroups-in-cgroup_post_fork.patch cgroups-fix-cgroup_iter_next-bug.patch cgroups-dont-put-struct-cgroupfs_root-protected-by-rcu.patch cgroups-use-task_lock-for-access-tsk-cgroups-safe-in-cgroup_clone.patch cgroups-call-find_css_set-safely-in-cgroup_attach_task.patch cgroups-remove-rcu_read_lock-in-cgroupstats_build.patch cgroups-make-root_list-contains-active-hierarchies-only.patch cgroups-add-inactive-subsystems-to-rootnodesubsys_list.patch cgroups-introduce-link_css_set-to-remove-duplicate-code.patch devcgroup-use-list_for_each_entry_rcu.patch memcg-introduce-charge-commit-cancel-style-of-functions.patch memcg-introduce-charge-commit-cancel-style-of-functions-fix.patch memcg-fix-gfp_mask-of-callers-of-charge.patch memcg-simple-migration-handling.patch memcg-do-not-recalculate-section-unnecessarily-in-init_section_page_cgroup.patch memcg-move-all-acccounts-to-parent-at-rmdir.patch memcg-reduce-size-of-mem_cgroup-by-using-nr_cpu_ids.patch memcg-new-force_empty-to-free-pages-under-group.patch memcg-new-force_empty-to-free-pages-under-group-fix.patch memcg-new-force_empty-to-free-pages-under-group-fix-fix.patch memcg-handle-swap-caches.patch memcg-handle-swap-caches-build-fix.patch memcg-memswap-controller-kconfig.patch memcg-swap-cgroup-for-remembering-usage.patch memcg-memswap-controller-core.patch memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch memcg-memswap-controller-core-swapcache-fixes.patch memcg-synchronized-lru.patch memcg-add-mem_cgroup_disabled.patch memcg-add-mem_cgroup_disabled-fix.patch memory-cgroup-hierarchy-documentation-v4.patch memory-cgroup-resource-counters-for-hierarchy-v4.patch memory-cgroup-resource-counters-for-hierarchy-v4-checkpatch-fixes.patch memory-cgroup-hierarchical-reclaim-v4.patch memory-cgroup-hierarchical-reclaim-v4-checkpatch-fixes.patch memory-cgroup-hierarchical-reclaim-v4-fix-for-hierarchical-reclaim.patch memory-cgroup-hierarchy-feature-selector-v4.patch memory-cgroup-hierarchy-feature-selector-v4-fix.patch memcontrol-rcu_read_lock-to-protect-mm_match_cgroup.patch memcg-avoid-unnecessary-system-wide-oom-killer.patch memcg-avoid-unnecessary-system-wide-oom-killer-fix.patch memcg-fix-reclaim-result-checks.patch cpuset-rcu_read_lock-to-protect-task_cs.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html