From: yangge <yangge1116@126.com> stable inclusion from stable-v6.6.37 commit c5978b996260534aca5ff1b6dcbef92c2bbea947 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAD6H2 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit bf14ed81f571f8dba31cd72ab2e50fbcc877cc31 upstream. Since commit 5d0a661d808f ("mm/page_alloc: use only one PCP list for THP-sized allocations") no longer differentiates the migration type of pages in THP-sized PCP list, it's possible that non-movable allocation requests may get a CMA page from the list, in some cases, it's not acceptable. If a large number of CMA memory are configured in system (for example, the CMA memory accounts for 50% of the system memory), starting a virtual machine with device passthrough will get stuck. During starting the virtual machine, it will call pin_user_pages_remote(..., FOLL_LONGTERM, ...) to pin memory. Normally if a page is present and in CMA area, pin_user_pages_remote() will migrate the page from CMA area to non-CMA area because of FOLL_LONGTERM flag. But if non-movable allocation requests return CMA memory, migrate_longterm_unpinnable_pages() will migrate a CMA page to another CMA page, which will fail to pass the check in check_and_migrate_movable_pages() and cause migration endless. Call trace: pin_user_pages_remote --__gup_longterm_locked // endless loops in this function ----_get_user_pages_locked ----check_and_migrate_movable_pages ------migrate_longterm_unpinnable_pages --------alloc_migration_target This problem will also have a negative impact on CMA itself. For example, when CMA is borrowed by THP, and we need to reclaim it through cma_alloc() or dma_alloc_coherent(), we must move those pages out to ensure CMA's users can retrieve that contigous memory. Currently, CMA's memory is occupied by non-movable pages, meaning we can't relocate them. As a result, cma_alloc() is more likely to fail. To fix the problem above, we add one PCP list for THP, which will not introduce a new cacheline for struct per_cpu_pages. THP will have 2 PCP lists, one PCP list is used by MOVABLE allocation, and the other PCP list is used by UNMOVABLE allocation. MOVABLE allocation contains GPF_MOVABLE, and UNMOVABLE allocation contains GFP_UNMOVABLE and GFP_RECLAIMABLE. Link: https://lkml.kernel.org/r/1718845190-4456-1-git-send-email-yangge1116@126.co... Fixes: 5d0a661d808f ("mm/page_alloc: use only one PCP list for THP-sized allocations") Signed-off-by: yangge <yangge1116@126.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <21cnbao@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: mm/page_alloc.c include/linux/mmzone.h [Conflicts due to ab3141753341 ("mm: prepare more high-order pages to be stored on the per-cpu lists")] Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com> --- include/linux/mmzone.h | 9 ++++----- mm/page_alloc.c | 9 +++++++-- 2 files changed, 11 insertions(+), 7 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index ec1d63cbc2e0..f76cc19b7fcd 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -678,13 +678,12 @@ enum zone_watermarks { }; /* - * One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. One additional list - * for THP which will usually be GFP_MOVABLE. Even if it is another type, - * it should not contribute to serious fragmentation causing THP allocation - * failures. + * One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. Two additional lists + * are added for THP. One PCP list is used by GPF_MOVABLE, and the other PCP list + * is used by GFP_UNMOVABLE and GFP_RECLAIMABLE. */ #ifdef CONFIG_TRANSPARENT_HUGEPAGE -#define NR_PCP_THP 1 +#define NR_PCP_THP 2 #define NR_PCP_ORDERS (PAGE_ALLOC_COSTLY_ORDER + 2) #else #define NR_PCP_THP 0 diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c63081268df4..a88c51df703f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -528,10 +528,15 @@ static void bad_page(struct page *page, const char *reason) static inline unsigned int order_to_pindex(int migratetype, int order) { + bool __maybe_unused movable; + #ifdef CONFIG_TRANSPARENT_HUGEPAGE if (order > PAGE_ALLOC_COSTLY_ORDER + 1) { VM_BUG_ON(order != HPAGE_PMD_ORDER); - return NR_LOWORDER_PCP_LISTS; + + movable = migratetype == MIGRATE_MOVABLE; + + return NR_LOWORDER_PCP_LISTS + movable; } #else VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); @@ -545,7 +550,7 @@ static inline int pindex_to_order(unsigned int pindex) int order = pindex / MIGRATE_PCPTYPES; #ifdef CONFIG_TRANSPARENT_HUGEPAGE - if (pindex == NR_LOWORDER_PCP_LISTS) + if (pindex >= NR_LOWORDER_PCP_LISTS) order = HPAGE_PMD_ORDER; #else VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); -- 2.34.1