From: Matthew Wilcox <willy@xxxxxxxxxxxxx> Subject: mm: account PMD tables like PTE tables We account the PTE level of the page tables to the process in order to make smarter OOM decisions and help diagnose why memory is fragmented. For these same reasons, we should account pages allocated for PMDs. With larger process address spaces and ASLR, the number of PMDs in use is higher than it used to be so the inaccuracy is starting to matter. [rppt@xxxxxxxxxxxxx: arm: __pmd_free_tlb(): call page table destructor] Link: https://lkml.kernel.org/r/20200825111303.GB69694@xxxxxxxxxxxxx Link: http://lkml.kernel.org/r/20200627184642.GF25039@xxxxxxxxxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: Abdul Haleem <abdhalee@xxxxxxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Cc: Joerg Roedel <joro@xxxxxxxxxx> Cc: Max Filippov <jcmvbkbc@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Satheesh Rajendran <sathnaga@xxxxxxxxxxxxxxxxxx> Cc: Stafford Horne <shorne@xxxxxxxxx> Cc: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> Cc: Anders Roxell <anders.roxell@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm/include/asm/tlb.h | 1 + include/linux/mm.h | 24 ++++++++++++++++++++---- 2 files changed, 21 insertions(+), 4 deletions(-) --- a/arch/arm/include/asm/tlb.h~mm-account-pmd-tables-like-pte-tables +++ a/arch/arm/include/asm/tlb.h @@ -59,6 +59,7 @@ __pmd_free_tlb(struct mmu_gather *tlb, p #ifdef CONFIG_ARM_LPAE struct page *page = virt_to_page(pmdp); + pgtable_pmd_page_dtor(page); tlb_remove_table(tlb, page); #endif } --- a/include/linux/mm.h~mm-account-pmd-tables-like-pte-tables +++ a/include/linux/mm.h @@ -2254,7 +2254,7 @@ static inline spinlock_t *pmd_lockptr(st return ptlock_ptr(pmd_to_page(pmd)); } -static inline bool pgtable_pmd_page_ctor(struct page *page) +static inline bool pmd_ptlock_init(struct page *page) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE page->pmd_huge_pte = NULL; @@ -2262,7 +2262,7 @@ static inline bool pgtable_pmd_page_ctor return ptlock_init(page); } -static inline void pgtable_pmd_page_dtor(struct page *page) +static inline void pmd_ptlock_free(struct page *page) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE VM_BUG_ON_PAGE(page->pmd_huge_pte, page); @@ -2279,8 +2279,8 @@ static inline spinlock_t *pmd_lockptr(st return &mm->page_table_lock; } -static inline bool pgtable_pmd_page_ctor(struct page *page) { return true; } -static inline void pgtable_pmd_page_dtor(struct page *page) {} +static inline bool pmd_ptlock_init(struct page *page) { return true; } +static inline void pmd_ptlock_free(struct page *page) {} #define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte) @@ -2293,6 +2293,22 @@ static inline spinlock_t *pmd_lock(struc return ptl; } +static inline bool pgtable_pmd_page_ctor(struct page *page) +{ + if (!pmd_ptlock_init(page)) + return false; + __SetPageTable(page); + inc_zone_page_state(page, NR_PAGETABLE); + return true; +} + +static inline void pgtable_pmd_page_dtor(struct page *page) +{ + pmd_ptlock_free(page); + __ClearPageTable(page); + dec_zone_page_state(page, NR_PAGETABLE); +} + /* * No scalability reason to split PUD locks yet, but follow the same pattern * as the PMD locks to make it easier if we decide to. The VM should not be _
