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mm: properly separate the bloated ptl from the regular case
Use kernel/bounds.c to convert build-time spinlock_t size check into a preprocessor symbol and apply that to properly separate the page::ptl situation. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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49076ec2cc
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539edb5846
4 changed files with 25 additions and 21 deletions
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@ -1317,27 +1317,29 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a
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#endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
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#if USE_SPLIT_PTE_PTLOCKS
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bool __ptlock_alloc(struct page *page);
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void __ptlock_free(struct page *page);
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#if BLOATED_SPINLOCKS
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extern bool ptlock_alloc(struct page *page);
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extern void ptlock_free(struct page *page);
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static inline spinlock_t *ptlock_ptr(struct page *page)
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{
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return page->ptl;
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}
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#else /* BLOATED_SPINLOCKS */
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static inline bool ptlock_alloc(struct page *page)
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{
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if (sizeof(spinlock_t) > sizeof(page->ptl))
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return __ptlock_alloc(page);
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return true;
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}
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static inline void ptlock_free(struct page *page)
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{
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if (sizeof(spinlock_t) > sizeof(page->ptl))
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__ptlock_free(page);
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}
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static inline spinlock_t *ptlock_ptr(struct page *page)
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{
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if (sizeof(spinlock_t) > sizeof(page->ptl))
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return (spinlock_t *) page->ptl;
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else
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return (spinlock_t *) &page->ptl;
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return &page->ptl;
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}
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#endif /* BLOATED_SPINLOCKS */
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static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
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{
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@ -1354,7 +1356,7 @@ static inline bool ptlock_init(struct page *page)
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* slab code uses page->slab_cache and page->first_page (for tail
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* pages), which share storage with page->ptl.
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*/
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VM_BUG_ON(page->ptl);
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VM_BUG_ON(*(unsigned long *)&page->ptl);
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if (!ptlock_alloc(page))
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return false;
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spin_lock_init(ptlock_ptr(page));
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@ -147,10 +147,11 @@ struct page {
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* system if PG_buddy is set.
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*/
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#if USE_SPLIT_PTE_PTLOCKS
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unsigned long ptl; /* It's spinlock_t if it fits to long,
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* otherwise it's pointer to dynamicaly
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* allocated spinlock_t.
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*/
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#if BLOATED_SPINLOCKS
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spinlock_t *ptl;
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#else
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spinlock_t ptl;
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#endif
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#endif
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struct kmem_cache *slab_cache; /* SL[AU]B: Pointer to slab */
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struct page *first_page; /* Compound tail pages */
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@ -11,6 +11,7 @@
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#include <linux/kbuild.h>
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#include <linux/page_cgroup.h>
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#include <linux/log2.h>
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#include <linux/spinlock.h>
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void foo(void)
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{
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@ -21,5 +22,6 @@ void foo(void)
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#ifdef CONFIG_SMP
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DEFINE(NR_CPUS_BITS, ilog2(CONFIG_NR_CPUS));
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#endif
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DEFINE(BLOATED_SPINLOCKS, sizeof(spinlock_t) > sizeof(int));
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/* End of constants */
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}
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11
mm/memory.c
11
mm/memory.c
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@ -4271,21 +4271,20 @@ void copy_user_huge_page(struct page *dst, struct page *src,
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}
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
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#if USE_SPLIT_PTE_PTLOCKS
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bool __ptlock_alloc(struct page *page)
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#if USE_SPLIT_PTE_PTLOCKS && BLOATED_SPINLOCKS
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bool ptlock_alloc(struct page *page)
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{
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spinlock_t *ptl;
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ptl = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
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if (!ptl)
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return false;
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page->ptl = (unsigned long)ptl;
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page->ptl = ptl;
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return true;
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}
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void __ptlock_free(struct page *page)
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void ptlock_free(struct page *page)
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{
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if (sizeof(spinlock_t) > sizeof(page->ptl))
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kfree((spinlock_t *)page->ptl);
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kfree(page->ptl);
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}
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#endif
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