mm: Introduce atomic_remove_mapping
For release page from atomic context(ie, softirq), locks
related to the work should be aware of that.
There are two locks.
One is mapping->tree_lock and the other is swap_info_struct->lock.
The mapping->tree_lock is alreay aware of irq so it's no problem
but swap_info_struct->lock isn't so atomic_remove_mapping uses just
try_spinlock and if it fails to hold a lock, it just depends on
a fallback plan which moves the page into LRU's tail and expect page
freeing in next.
A change I know is mapping->a_ops->free is called on atomic context
by this patch. Only user is nfs_readdir_clear_array which is no
problem when I look at.
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
3 files changed
