diff options
author | Mel Gorman <mgorman@suse.de> | 2012-10-25 12:16:31 (GMT) |
---|---|---|
committer | Mel Gorman <mgorman@suse.de> | 2012-12-11 14:42:39 (GMT) |
commit | d10e63f29488b0f312a443f9507ea9b6fd3c9090 (patch) | |
tree | b39e3caa5d25e9e5ebad84c606a724e25c6b8e91 | |
parent | 1ba6e0b50b479cbadb8f05ebde3020da9ac87201 (diff) | |
download | linux-d10e63f29488b0f312a443f9507ea9b6fd3c9090.tar.xz |
mm: numa: Create basic numa page hinting infrastructure
Note: This patch started as "mm/mpol: Create special PROT_NONE
infrastructure" and preserves the basic idea but steals *very*
heavily from "autonuma: numa hinting page faults entry points" for
the actual fault handlers without the migration parts. The end
result is barely recognisable as either patch so all Signed-off
and Reviewed-bys are dropped. If Peter, Ingo and Andrea are ok with
this version, I will re-add the signed-offs-by to reflect the history.
In order to facilitate a lazy -- fault driven -- migration of pages, create
a special transient PAGE_NUMA variant, we can then use the 'spurious'
protection faults to drive our migrations from.
The meaning of PAGE_NUMA depends on the architecture but on x86 it is
effectively PROT_NONE. Actual PROT_NONE mappings will not generate these
NUMA faults for the reason that the page fault code checks the permission on
the VMA (and will throw a segmentation fault on actual PROT_NONE mappings),
before it ever calls handle_mm_fault.
[dhillf@gmail.com: Fix typo]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
-rw-r--r-- | include/linux/huge_mm.h | 10 | ||||
-rw-r--r-- | mm/huge_memory.c | 22 | ||||
-rw-r--r-- | mm/memory.c | 112 |
3 files changed, 141 insertions, 3 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index b31cb7d..a1d26a9 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -159,6 +159,10 @@ static inline struct page *compound_trans_head(struct page *page) } return page; } + +extern int do_huge_pmd_numa_page(struct mm_struct *mm, unsigned long addr, + pmd_t pmd, pmd_t *pmdp); + #else /* CONFIG_TRANSPARENT_HUGEPAGE */ #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; }) #define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; }) @@ -195,6 +199,12 @@ static inline int pmd_trans_huge_lock(pmd_t *pmd, { return 0; } + +static inline int do_huge_pmd_numa_page(struct mm_struct *mm, unsigned long addr, + pmd_t pmd, pmd_t *pmdp) +{ +} + #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #endif /* _LINUX_HUGE_MM_H */ diff --git a/mm/huge_memory.c b/mm/huge_memory.c index cd24aa5..f5f3763 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1018,6 +1018,28 @@ out: return page; } +/* 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) +{ + struct page *page; + unsigned long haddr = addr & HPAGE_PMD_MASK; + + spin_lock(&mm->page_table_lock); + if (unlikely(!pmd_same(pmd, *pmdp))) + goto out_unlock; + + page = pmd_page(pmd); + pmd = pmd_mknonnuma(pmd); + set_pmd_at(mm, haddr, pmdp, pmd); + VM_BUG_ON(pmd_numa(*pmdp)); + update_mmu_cache_pmd(vma, addr, pmdp); + +out_unlock: + spin_unlock(&mm->page_table_lock); + return 0; +} + int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr) { diff --git a/mm/memory.c b/mm/memory.c index cd8e0da..e30616f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3448,6 +3448,103 @@ static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); } +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; + spinlock_t *ptl; + + /* + * The "pte" at this point cannot be used safely without + * validation through pte_unmap_same(). It's of NUMA type but + * the pfn may be screwed if the read is non atomic. + * + * ptep_modify_prot_start is not called as this is clearing + * the _PAGE_NUMA bit and it is not really expected that there + * would be concurrent hardware modifications to the PTE. + */ + ptl = pte_lockptr(mm, pmd); + spin_lock(ptl); + if (unlikely(!pte_same(*ptep, pte))) + goto out_unlock; + pte = pte_mknonnuma(pte); + set_pte_at(mm, addr, ptep, pte); + update_mmu_cache(vma, addr, ptep); + + page = vm_normal_page(vma, addr, pte); + if (!page) { + pte_unmap_unlock(ptep, ptl); + return 0; + } + +out_unlock: + pte_unmap_unlock(ptep, ptl); + return 0; +} + +/* NUMA hinting page fault entry point for regular pmds */ +#ifdef CONFIG_NUMA_BALANCING +static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long addr, pmd_t *pmdp) +{ + pmd_t pmd; + pte_t *pte, *orig_pte; + unsigned long _addr = addr & PMD_MASK; + unsigned long offset; + spinlock_t *ptl; + bool numa = false; + + spin_lock(&mm->page_table_lock); + pmd = *pmdp; + if (pmd_numa(pmd)) { + set_pmd_at(mm, _addr, pmdp, pmd_mknonnuma(pmd)); + numa = true; + } + spin_unlock(&mm->page_table_lock); + + if (!numa) + return 0; + + /* we're in a page fault so some vma must be in the range */ + BUG_ON(!vma); + BUG_ON(vma->vm_start >= _addr + PMD_SIZE); + offset = max(_addr, vma->vm_start) & ~PMD_MASK; + VM_BUG_ON(offset >= PMD_SIZE); + orig_pte = pte = pte_offset_map_lock(mm, pmdp, _addr, &ptl); + pte += offset >> PAGE_SHIFT; + for (addr = _addr + offset; addr < _addr + PMD_SIZE; pte++, addr += PAGE_SIZE) { + pte_t pteval = *pte; + struct page *page; + if (!pte_present(pteval)) + continue; + if (!pte_numa(pteval)) + continue; + if (addr >= vma->vm_end) { + vma = find_vma(mm, addr); + /* there's a pte present so there must be a vma */ + BUG_ON(!vma); + BUG_ON(addr < vma->vm_start); + } + if (pte_numa(pteval)) { + pteval = pte_mknonnuma(pteval); + set_pte_at(mm, addr, pte, pteval); + } + page = vm_normal_page(vma, addr, pteval); + if (unlikely(!page)) + continue; + } + pte_unmap_unlock(orig_pte, ptl); + + return 0; +} +#else +static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long addr, pmd_t *pmdp) +{ + BUG(); +} +#endif /* CONFIG_NUMA_BALANCING */ + /* * These routines also need to handle stuff like marking pages dirty * and/or accessed for architectures that don't do it in hardware (most @@ -3486,6 +3583,9 @@ int handle_pte_fault(struct mm_struct *mm, pte, pmd, flags, entry); } + if (pte_numa(entry)) + return do_numa_page(mm, vma, address, entry, pte, pmd); + ptl = pte_lockptr(mm, pmd); spin_lock(ptl); if (unlikely(!pte_same(*pte, entry))) @@ -3554,9 +3654,11 @@ retry: barrier(); if (pmd_trans_huge(orig_pmd)) { - if (flags & FAULT_FLAG_WRITE && - !pmd_write(orig_pmd) && - !pmd_trans_splitting(orig_pmd)) { + if (pmd_numa(*pmd)) + return do_huge_pmd_numa_page(mm, address, + orig_pmd, pmd); + + if ((flags & FAULT_FLAG_WRITE) && !pmd_write(orig_pmd)) { ret = do_huge_pmd_wp_page(mm, vma, address, pmd, orig_pmd); /* @@ -3568,10 +3670,14 @@ retry: goto retry; return ret; } + return 0; } } + if (pmd_numa(*pmd)) + return do_pmd_numa_page(mm, vma, address, pmd); + /* * Use __pte_alloc instead of pte_alloc_map, because we can't * run pte_offset_map on the pmd, if an huge pmd could |