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| author |   Hugh Dickins <hughd@google.com> | 2016-07-26 15:26:15 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-26 16:19:19 -0700 |
| commit | c01d5b300774d130a24d787825b01eb24e6e20cb (patch) | |
| tree | e56b92aa5cf8f25ab812da30db5b36a6126e877b /include/linux/shmem_fs.h | |
| parent | shmem: prepare huge= mount option and sysfs knob (diff) | |
| download | linux-dev-c01d5b300774d130a24d787825b01eb24e6e20cb.tar.xz linux-dev-c01d5b300774d130a24d787825b01eb24e6e20cb.zip | |
shmem: get_unmapped_area align huge page
Provide a shmem_get_unmapped_area method in file_operations, called at
mmap time to decide the mapping address. It could be conditional on
CONFIG_TRANSPARENT_HUGEPAGE, but save #ifdefs in other places by making
it unconditional.
shmem_get_unmapped_area() first calls the usual mm->get_unmapped_area
(which we treat as a black box, highly dependent on architecture and
config and executable layout). Lots of conditions, and in most cases it
just goes with the address that chose; but when our huge stars are
rightly aligned, yet that did not provide a suitable address, go back to
ask for a larger arena, within which to align the mapping suitably.
There have to be some direct calls to shmem_get_unmapped_area(), not via
the file_operations: because of the way shmem_zero_setup() is called to
create a shmem object late in the mmap sequence, when MAP_SHARED is
requested with MAP_ANONYMOUS or /dev/zero. Though this only matters
when /proc/sys/vm/shmem_huge has been set.
Link: http://lkml.kernel.org/r/1466021202-61880-29-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/shmem_fs.h')
| -rw-r--r-- | include/linux/shmem_fs.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 466f18c73a49..ff2de4bab61f 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -50,6 +50,8 @@ extern struct file *shmem_file_setup(const char *name, extern struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags); extern int shmem_zero_setup(struct vm_area_struct *); +extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, + unsigned long len, unsigned long pgoff, unsigned long flags); extern int shmem_lock(struct file *file, int lock, struct user_struct *user); extern bool shmem_mapping(struct address_space *mapping); extern void shmem_unlock_mapping(struct address_space *mapping); |