On Thu, May 24, 2018 at 12:50:11PM +0200, Jan Kara wrote:
On Thu 24-05-18 11:38:27, Greg Kroah-Hartman wrote:
4.4-stable review patch. If anyone has any objections, please let me know.
Just one objection: Why does stable care about this (and the previous patch)? I've checked the stable queue and I don't see anything that would have these patches as a prerequisite. And on their own, they are only cleanups without substantial gains.
There's a small gain here:
paralleldd 4.4.0 4.4.0 vanilla avoidlock Amean Elapsd-1 5.28 ( 0.00%) 5.15 ( 2.50%) Amean Elapsd-4 5.29 ( 0.00%) 5.17 ( 2.12%) Amean Elapsd-7 5.28 ( 0.00%) 5.18 ( 1.78%) Amean Elapsd-12 5.20 ( 0.00%) 5.33 ( -2.50%) Amean Elapsd-21 5.14 ( 0.00%) 5.21 ( -1.41%) Amean Elapsd-30 5.30 ( 0.00%) 5.12 ( 3.38%) Amean Elapsd-48 5.78 ( 0.00%) 5.42 ( 6.21%) Amean Elapsd-79 6.78 ( 0.00%) 6.62 ( 2.46%) Amean Elapsd-110 9.09 ( 0.00%) 8.99 ( 1.15%) Amean Elapsd-128 10.60 ( 0.00%) 10.43 ( 1.66%)
The impact is small but intuitively, it makes sense to avoid unnecessary calls to lock_page.
Yes, it's small, but it's marked in the SLES kernel as "needs to be merged into stable", so obviously it matters to someone :)
thanks,
greg k-h