diff options
author | Michel Lespinasse <walken@google.com> | 2013-02-22 19:32:37 -0500 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-23 20:50:10 -0500 |
commit | bebeb3d68b24bb4132d452c5707fe321208bcbcd (patch) | |
tree | 6e609cb7323fb1b4b7026fa0e35867145a181094 /ipc/shm.c | |
parent | 940e7da5163029978c2f6b5bbe213607add59062 (diff) |
mm: introduce mm_populate() for populating new vmas
When creating new mappings using the MAP_POPULATE / MAP_LOCKED flags (or
with MCL_FUTURE in effect), we want to populate the pages within the
newly created vmas. This may take a while as we may have to read pages
from disk, so ideally we want to do this outside of the write-locked
mmap_sem region.
This change introduces mm_populate(), which is used to defer populating
such mappings until after the mmap_sem write lock has been released.
This is implemented as a generalization of the former do_mlock_pages(),
which accomplished the same task but was using during mlock() /
mlockall().
Signed-off-by: Michel Lespinasse <walken@google.com>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Rik van Riel <riel@redhat.com>
Tested-by: Andy Lutomirski <luto@amacapital.net>
Cc: Greg Ungerer <gregungerer@westnet.com.au>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc/shm.c')
-rw-r--r-- | ipc/shm.c | 12 |
1 files changed, 7 insertions, 5 deletions
@@ -967,11 +967,11 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr, | |||
967 | unsigned long flags; | 967 | unsigned long flags; |
968 | unsigned long prot; | 968 | unsigned long prot; |
969 | int acc_mode; | 969 | int acc_mode; |
970 | unsigned long user_addr; | ||
971 | struct ipc_namespace *ns; | 970 | struct ipc_namespace *ns; |
972 | struct shm_file_data *sfd; | 971 | struct shm_file_data *sfd; |
973 | struct path path; | 972 | struct path path; |
974 | fmode_t f_mode; | 973 | fmode_t f_mode; |
974 | bool populate = false; | ||
975 | 975 | ||
976 | err = -EINVAL; | 976 | err = -EINVAL; |
977 | if (shmid < 0) | 977 | if (shmid < 0) |
@@ -1070,13 +1070,15 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr, | |||
1070 | goto invalid; | 1070 | goto invalid; |
1071 | } | 1071 | } |
1072 | 1072 | ||
1073 | user_addr = do_mmap_pgoff(file, addr, size, prot, flags, 0); | 1073 | addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate); |
1074 | *raddr = user_addr; | 1074 | *raddr = addr; |
1075 | err = 0; | 1075 | err = 0; |
1076 | if (IS_ERR_VALUE(user_addr)) | 1076 | if (IS_ERR_VALUE(addr)) |
1077 | err = (long)user_addr; | 1077 | err = (long)addr; |
1078 | invalid: | 1078 | invalid: |
1079 | up_write(¤t->mm->mmap_sem); | 1079 | up_write(¤t->mm->mmap_sem); |
1080 | if (populate) | ||
1081 | mm_populate(addr, size); | ||
1080 | 1082 | ||
1081 | out_fput: | 1083 | out_fput: |
1082 | fput(file); | 1084 | fput(file); |