From 4daae3b4b9e49b7e0935499a352f1c59d90287d2 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Fri, 2 Nov 2012 11:33:45 +0000 Subject: mm: mempolicy: Use _PAGE_NUMA to migrate pages Note: Based on "mm/mpol: Use special PROT_NONE to migrate pages" but sufficiently different that the signed-off-bys were dropped Combine our previous _PAGE_NUMA, mpol_misplaced and migrate_misplaced_page() pieces into an effective migrate on fault scheme. Note that (on x86) we rely on PROT_NONE pages being !present and avoid the TLB flush from try_to_unmap(TTU_MIGRATION). This greatly improves the page-migration performance. Based-on-work-by: Peter Zijlstra Signed-off-by: Mel Gorman --- mm/huge_memory.c | 31 ++++++++++++++++++++++++++++--- mm/memory.c | 32 +++++++++++++++++++++++++++----- 2 files changed, 55 insertions(+), 8 deletions(-) (limited to 'mm') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index f5f37630c54..5723b551c02 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include "internal.h" @@ -1019,17 +1020,39 @@ out: } /* NUMA hinting page fault entry point for trans huge pmds */ -int do_huge_pmd_numa_page(struct mm_struct *mm, unsigned long addr, - pmd_t pmd, pmd_t *pmdp) +int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long addr, pmd_t pmd, pmd_t *pmdp) { - struct page *page; + struct page *page = NULL; unsigned long haddr = addr & HPAGE_PMD_MASK; + int target_nid; spin_lock(&mm->page_table_lock); if (unlikely(!pmd_same(pmd, *pmdp))) goto out_unlock; page = pmd_page(pmd); + get_page(page); + spin_unlock(&mm->page_table_lock); + + target_nid = mpol_misplaced(page, vma, haddr); + if (target_nid == -1) + goto clear_pmdnuma; + + /* + * Due to lacking code to migrate thp pages, we'll split + * (which preserves the special PROT_NONE) and re-take the + * fault on the normal pages. + */ + split_huge_page(page); + put_page(page); + return 0; + +clear_pmdnuma: + spin_lock(&mm->page_table_lock); + if (unlikely(!pmd_same(pmd, *pmdp))) + goto out_unlock; + pmd = pmd_mknonnuma(pmd); set_pmd_at(mm, haddr, pmdp, pmd); VM_BUG_ON(pmd_numa(*pmdp)); @@ -1037,6 +1060,8 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, unsigned long addr, out_unlock: spin_unlock(&mm->page_table_lock); + if (page) + put_page(page); return 0; } diff --git a/mm/memory.c b/mm/memory.c index e30616f2cc3..d52542680e1 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -57,6 +57,7 @@ #include #include #include +#include #include #include @@ -3451,8 +3452,9 @@ static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd) { - struct page *page; + struct page *page = NULL; spinlock_t *ptl; + int current_nid, target_nid; /* * The "pte" at this point cannot be used safely without @@ -3465,8 +3467,11 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, */ ptl = pte_lockptr(mm, pmd); spin_lock(ptl); - if (unlikely(!pte_same(*ptep, pte))) - goto out_unlock; + if (unlikely(!pte_same(*ptep, pte))) { + pte_unmap_unlock(ptep, ptl); + goto out; + } + pte = pte_mknonnuma(pte); set_pte_at(mm, addr, ptep, pte); update_mmu_cache(vma, addr, ptep); @@ -3477,8 +3482,25 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, return 0; } -out_unlock: + get_page(page); + current_nid = page_to_nid(page); + target_nid = mpol_misplaced(page, vma, addr); pte_unmap_unlock(ptep, ptl); + if (target_nid == -1) { + /* + * Account for the fault against the current node if it not + * being replaced regardless of where the page is located. + */ + current_nid = numa_node_id(); + put_page(page); + goto out; + } + + /* Migrate to the requested node */ + if (migrate_misplaced_page(page, target_nid)) + current_nid = target_nid; + +out: return 0; } @@ -3655,7 +3677,7 @@ retry: barrier(); if (pmd_trans_huge(orig_pmd)) { if (pmd_numa(*pmd)) - return do_huge_pmd_numa_page(mm, address, + return do_huge_pmd_numa_page(mm, vma, address, orig_pmd, pmd); if ((flags & FAULT_FLAG_WRITE) && !pmd_write(orig_pmd)) { -- cgit v1.2.3