On Sat, Feb 01, 2020 at 01:49:31PM +0800, qiwuchen55@xxxxxxxxx wrote:
> Apparently our current rwsem code doesn't like doing the trylock, then
> lock for real scheme. So change our direct write method to just do the
> trylock for the RWF_NOWAIT case.
> This seems to fix AIM7 regression in some scalable filesystems upto ~25%
> in some cases. Claimed in commit 942491c9e6d6 ("xfs: fix AIM7 regression")
This commit message doesn't match the patch.
> /* Don't allow parallel writes to the same file */
> - inode_lock(inode);
> + if (iocb->ki_flags & IOCB_NOWAIT) {
> + if (!inode_trylock(inode))
> + return -EAGAIN;
> + } else {
> + inode_lock(inode);
> + }
> +
> res = generic_write_checks(iocb, from);
> if (res > 0) {
> if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
> --
> 1.9.1
>
