@@ -143,7 +143,7 @@ using a number of wrapper functions:
Query the address space, and return true if it is completely
unevictable.
-These are currently used in two places in the kernel:
+These are currently used in three places in the kernel:
(1) By ramfs to mark the address spaces of its inodes when they are created,
and this mark remains for the life of the inode.
@@ -154,6 +154,8 @@ These are currently used in two places in the kernel:
swapped out; the application must touch the pages manually if it wants to
ensure they're in memory.
+ (3) By the i915 driver to mark pinned address space until it's unpinned.
+
Detecting Unevictable Pages
---------------------------
@@ -786,6 +786,7 @@ void shmem_unlock_mapping(struct address_space *mapping)
cond_resched();
}
}
+EXPORT_SYMBOL_GPL(shmem_unlock_mapping);
/*
* Remove range of pages and swap entries from radix tree, and free them.
@@ -3874,6 +3875,7 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user)
void shmem_unlock_mapping(struct address_space *mapping)
{
}
+EXPORT_SYMBOL_GPL(shmem_unlock_mapping);
#ifdef CONFIG_MMU
unsigned long shmem_get_unmapped_area(struct file *file,
By exporting this function, drivers can mark/unmark a shmemfs address space as unevictable in the following way: 1. mark an address space as unevictable with mapping_set_unevictable(), pages in the address space will be moved to unevictable list in vmscan. 2. mark an address space evictable with mapping_clear_unevictable(), and move these pages back to evictable list with shmem_unlock_mapping(). Signed-off-by: Kuo-Hsin Yang <vovoy@chromium.org> --- Documentation/vm/unevictable-lru.rst | 4 +++- mm/shmem.c | 2 ++ 2 files changed, 5 insertions(+), 1 deletion(-)