diff options
| author | Michal Hocko <mhocko@suse.com> | 2016-10-11 13:56:04 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-11 15:06:34 -0700 |
| commit | 9c5d760b8d229b94c5030863a5edaee5f1a9d7b7 (patch) | |
| tree | 2f8c87133c512712c23c9f79926c8f966953d64e /include/linux/fs.h | |
| parent | 5114a97a8bce7f4ead29a32b67dee85438699b9e (diff) | |
mm: split gfp_mask and mapping flags into separate fields
mapping->flags currently encodes two different things into a single flag.
It contains sticky gfp_mask for page cache allocations and AS_ codes used
to report errors/enospace and other states which are mapping specific.
Condensing the two semantically unrelated things saves few bytes but it
also complicates other things. For one thing the gfp flags space is
reduced and in fact we are already running out of available bits. It can
be assumed that more gfp flags will be necessary later on.
To not introduce the address_space grow (at least on x86_64) we can stick
it right after private_lock because we have a hole there.
struct address_space {
struct inode * host; /* 0 8 */
struct radix_tree_root page_tree; /* 8 16 */
spinlock_t tree_lock; /* 24 4 */
atomic_t i_mmap_writable; /* 28 4 */
struct rb_root i_mmap; /* 32 8 */
struct rw_semaphore i_mmap_rwsem; /* 40 40 */
/* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */
long unsigned int nrpages; /* 80 8 */
long unsigned int nrexceptional; /* 88 8 */
long unsigned int writeback_index; /* 96 8 */
const struct address_space_operations * a_ops; /* 104 8 */
long unsigned int flags; /* 112 8 */
spinlock_t private_lock; /* 120 4 */
/* XXX 4 bytes hole, try to pack */
/* --- cacheline 2 boundary (128 bytes) --- */
struct list_head private_list; /* 128 16 */
void * private_data; /* 144 8 */
/* size: 152, cachelines: 3, members: 14 */
/* sum members: 148, holes: 1, sum holes: 4 */
/* last cacheline: 24 bytes */
};
Link: http://lkml.kernel.org/r/20160912114852.GI14524@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/fs.h')
| -rw-r--r-- | include/linux/fs.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index c145219286a8..bc65d5918140 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -440,8 +440,9 @@ struct address_space { unsigned long nrexceptional; pgoff_t writeback_index;/* writeback starts here */ const struct address_space_operations *a_ops; /* methods */ - unsigned long flags; /* error bits/gfp mask */ + unsigned long flags; /* error bits */ spinlock_t private_lock; /* for use by the address_space */ + gfp_t gfp_mask; /* implicit gfp mask for allocations */ struct list_head private_list; /* ditto */ void *private_data; /* ditto */ } __attribute__((aligned(sizeof(long)))); |