shmem_get_unmapped_area() provides a functionality similar to __thp_get_unmapped_area() as both allocate a pmd-aligned address.
Change shmem_get_unmapped_area() to do shm-specific checks and then call __thp_get_unmapped_area() for allocating a pmd-aligned address. link: https://lkml.org/lkml/2016/8/29/620 Suggested-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com> Signed-off-by: Toshi Kani <toshi.k...@hpe.com> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Kirill A. Shutemov <kirill.shute...@linux.intel.com> Cc: Hugh Dickins <hu...@google.com> Cc: Matthew Wilcox <mawil...@microsoft.com> Cc: Dan Williams <dan.j.willi...@intel.com> --- include/linux/huge_mm.h | 10 +++++++ mm/shmem.c | 68 +++++++++-------------------------------------- 2 files changed, 23 insertions(+), 55 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 4fca526..1b65924 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -90,6 +90,9 @@ extern unsigned long transparent_hugepage_flags; extern unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); +extern unsigned long __thp_get_unmapped_area(struct file *filp, + unsigned long len, loff_t off, unsigned long flags, + unsigned long size); extern void prep_transhuge_page(struct page *page); extern void free_transhuge_page(struct page *page); @@ -176,6 +179,13 @@ static inline void prep_transhuge_page(struct page *page) {} #define thp_get_unmapped_area NULL +static inline unsigned long __thp_get_unmapped_area(struct file *filp, + unsigned long len, loff_t off, unsigned long flags, + unsigned long size) +{ + return 0; +} + static inline int split_huge_page_to_list(struct page *page, struct list_head *list) { diff --git a/mm/shmem.c b/mm/shmem.c index aec5b49..ef27455 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1925,45 +1925,23 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) } unsigned long shmem_get_unmapped_area(struct file *file, - unsigned long uaddr, unsigned long len, + unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { - unsigned long (*get_area)(struct file *, - unsigned long, unsigned long, unsigned long, unsigned long); - unsigned long addr; - unsigned long offset; - unsigned long inflated_len; - unsigned long inflated_addr; - unsigned long inflated_offset; - - if (len > TASK_SIZE) - return -ENOMEM; - - get_area = current->mm->get_unmapped_area; - addr = get_area(file, uaddr, len, pgoff, flags); + loff_t off = (loff_t)pgoff << PAGE_SHIFT; if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) - return addr; - if (IS_ERR_VALUE(addr)) - return addr; - if (addr & ~PAGE_MASK) - return addr; - if (addr > TASK_SIZE - len) - return addr; - + goto out; if (shmem_huge == SHMEM_HUGE_DENY) - return addr; - if (len < HPAGE_PMD_SIZE) - return addr; - if (flags & MAP_FIXED) - return addr; + goto out; + /* * Our priority is to support MAP_SHARED mapped hugely; * and support MAP_PRIVATE mapped hugely too, until it is COWed. * But if caller specified an address hint, respect that as before. */ - if (uaddr) - return addr; + if (addr) + goto out; if (shmem_huge != SHMEM_HUGE_FORCE) { struct super_block *sb; @@ -1977,39 +1955,19 @@ unsigned long shmem_get_unmapped_area(struct file *file, * for "/dev/zero", to create a shared anonymous object. */ if (IS_ERR(shm_mnt)) - return addr; + goto out; sb = shm_mnt->mnt_sb; } if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER) - return addr; + goto out; } - offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1); - if (offset && offset + len < 2 * HPAGE_PMD_SIZE) - return addr; - if ((addr & (HPAGE_PMD_SIZE-1)) == offset) - return addr; - - inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE; - if (inflated_len > TASK_SIZE) - return addr; - if (inflated_len < len) - return addr; - - inflated_addr = get_area(NULL, 0, inflated_len, 0, flags); - if (IS_ERR_VALUE(inflated_addr)) - return addr; - if (inflated_addr & ~PAGE_MASK) + addr = __thp_get_unmapped_area(file, len, off, flags, HPAGE_PMD_SIZE); + if (addr) return addr; - inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1); - inflated_addr += offset - inflated_offset; - if (inflated_offset > offset) - inflated_addr += HPAGE_PMD_SIZE; - - if (inflated_addr > TASK_SIZE - len) - return addr; - return inflated_addr; + out: + return current->mm->get_unmapped_area(file, addr, len, pgoff, flags); } #ifdef CONFIG_NUMA
