diff options
| -rw-r--r-- | mm/memory.c | 90 |
1 files changed, 56 insertions, 34 deletions
diff --git a/mm/memory.c b/mm/memory.c index d7b5b22a1a0a..65bb59e031c9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4599,71 +4599,93 @@ EXPORT_SYMBOL(__might_fault); #endif #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) -static void clear_gigantic_page(struct page *page, - unsigned long addr, - unsigned int pages_per_huge_page) -{ - int i; - struct page *p = page; - - might_sleep(); - for (i = 0; i < pages_per_huge_page; - i++, p = mem_map_next(p, page, i)) { - cond_resched(); - clear_user_highpage(p, addr + i * PAGE_SIZE); - } -} -void clear_huge_page(struct page *page, - unsigned long addr_hint, unsigned int pages_per_huge_page) +/* + * Process all subpages of the specified huge page with the specified + * operation. The target subpage will be processed last to keep its + * cache lines hot. + */ +static inline void process_huge_page( + unsigned long addr_hint, unsigned int pages_per_huge_page, + void (*process_subpage)(unsigned long addr, int idx, void *arg), + void *arg) { int i, n, base, l; unsigned long addr = addr_hint & ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); - if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { - clear_gigantic_page(page, addr, pages_per_huge_page); - return; - } - - /* Clear sub-page to access last to keep its cache lines hot */ + /* Process target subpage last to keep its cache lines hot */ might_sleep(); n = (addr_hint - addr) / PAGE_SIZE; if (2 * n <= pages_per_huge_page) { - /* If sub-page to access in first half of huge page */ + /* If target subpage in first half of huge page */ base = 0; l = n; - /* Clear sub-pages at the end of huge page */ + /* Process subpages at the end of huge page */ for (i = pages_per_huge_page - 1; i >= 2 * n; i--) { cond_resched(); - clear_user_highpage(page + i, addr + i * PAGE_SIZE); + process_subpage(addr + i * PAGE_SIZE, i, arg); } } else { - /* If sub-page to access in second half of huge page */ + /* If target subpage in second half of huge page */ base = pages_per_huge_page - 2 * (pages_per_huge_page - n); l = pages_per_huge_page - n; - /* Clear sub-pages at the begin of huge page */ + /* Process subpages at the begin of huge page */ for (i = 0; i < base; i++) { cond_resched(); - clear_user_highpage(page + i, addr + i * PAGE_SIZE); + process_subpage(addr + i * PAGE_SIZE, i, arg); } } /* - * Clear remaining sub-pages in left-right-left-right pattern - * towards the sub-page to access + * Process remaining subpages in left-right-left-right pattern + * towards the target subpage */ for (i = 0; i < l; i++) { int left_idx = base + i; int right_idx = base + 2 * l - 1 - i; cond_resched(); - clear_user_highpage(page + left_idx, - addr + left_idx * PAGE_SIZE); + process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg); cond_resched(); - clear_user_highpage(page + right_idx, - addr + right_idx * PAGE_SIZE); + process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg); } } +static void clear_gigantic_page(struct page *page, + unsigned long addr, + unsigned int pages_per_huge_page) +{ + int i; + struct page *p = page; + + might_sleep(); + for (i = 0; i < pages_per_huge_page; + i++, p = mem_map_next(p, page, i)) { + cond_resched(); + clear_user_highpage(p, addr + i * PAGE_SIZE); + } +} + +static void clear_subpage(unsigned long addr, int idx, void *arg) +{ + struct page *page = arg; + + clear_user_highpage(page + idx, addr); +} + +void clear_huge_page(struct page *page, + unsigned long addr_hint, unsigned int pages_per_huge_page) +{ + unsigned long addr = addr_hint & + ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1); + + if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { + clear_gigantic_page(page, addr, pages_per_huge_page); + return; + } + + process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page); +} + static void copy_user_gigantic_page(struct page *dst, struct page *src, unsigned long addr, struct vm_area_struct *vma, |