forked from torvalds/linux
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
fs/ufs: Replace kmap() with kmap_local_page()
kmap() is being deprecated in favor of kmap_local_page(). There are two main problems with kmap(): (1) It comes with an overhead as the mapping space is restricted and protected by a global lock for synchronization and (2) it also requires global TLB invalidation when the kmap’s pool wraps and it might block when the mapping space is fully utilized until a slot becomes available. With kmap_local_page() the mappings are per thread, CPU local, can take page faults, and can be called from any context (including interrupts). It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore, the tasks can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and still valid. Since its use in fs/ufs is safe everywhere, it should be preferred. Therefore, replace kmap() with kmap_local_page() in fs/ufs. kunmap_local() requires the mapping address, so return that address from ufs_get_page() to be used in ufs_put_page(). Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Suggested-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
- Loading branch information
1 parent
1c16cc4
commit 8d46ed8
Showing
1 changed file
with
47 additions
and
29 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters