Here's my attempt on fixing race in compound_head(). It should make compound_head() reliable in all contexts. The last patch is optional. It applies cleanly into mmotm patchstack just before my page-flags patchset. As expected, it causes few conflicts with patches: page-flags-introduce-page-flags-policies-wrt-compound-pages.patch mm-sanitize-page-mapping-for-tail-pages.patch include-linux-page-flagsh-rename-macros-to-avoid-collisions.patch Updated patches with solved conflicts can be found here: http://marc.info/?l=linux-kernel&m=144007388303804&q=p4 http://marc.info/?l=linux-kernel&m=144007388303804&q=p5 http://marc.info/?l=linux-kernel&m=144007388303804&q=p3 v5: - Fix collision with hugetlb_cgroup (see updated patch description in patch 5/7); v4: - init page->lru on init_reserved_page() for DEFERRED_STRUCT_PAGE_INIT=n; - fix zsmalloc breakage (repored by Sergey Senozhatsky); - move #ifdef CONFIG_64BIT into separate patch; - enum compound_dtor_id; - move pmd_huge_pte to other word to avoid conflict with compound_head; - compile-time LIST_POISON1 sanity check; - few cleanups around page->rcu_head; v3: - Fix build without hugetlb; - Drop page->first_page; - Update comment for free_compound_page(); - Use 'unsigned int' for page order; v2: Per Hugh's suggestion page->compound_head is moved into third double word. This way we can avoid memory overhead which v1 had in some cases. This place in struct page is rather overloaded. More testing is required to make sure we don't collide with anyone. Kirill A. Shutemov (7): mm: drop page->slab_page slub: use page->rcu_head instead of page->lru plus cast zsmalloc: use page->private instead of page->first_page mm: pack compound_dtor and compound_order into one word in struct page mm: make compound_head() robust mm: use 'unsigned int' for page order mm: use 'unsigned int' for compound_dtor/compound_order on 64BIT Documentation/vm/split_page_table_lock | 4 +- arch/xtensa/configs/iss_defconfig | 1 - include/linux/hugetlb_cgroup.h | 4 +- include/linux/mm.h | 82 ++++++++++----------------------- include/linux/mm_types.h | 30 ++++++++---- include/linux/page-flags.h | 80 ++++++++------------------------ mm/Kconfig | 12 ----- mm/debug.c | 5 -- mm/huge_memory.c | 3 +- mm/hugetlb.c | 35 +++++++------- mm/hugetlb_cgroup.c | 2 +- mm/internal.h | 8 ++-- mm/memory-failure.c | 7 --- mm/page_alloc.c | 84 ++++++++++++++++++++++------------ mm/slab.c | 17 ++----- mm/slub.c | 5 +- mm/swap.c | 4 +- mm/zsmalloc.c | 11 ++--- 18 files changed, 156 insertions(+), 238 deletions(-) -- 2.5.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>