On Thu 24-05-18 13:28:41, Greg KH wrote: > On Thu, May 24, 2018 at 04:17:12AM -0700, Hugh Dickins wrote: > > Thu, May 24, 2018 at 4:06 AM Greg Kroah-Hartman > > <gregkh@xxxxxxxxxxxxxxxxxxx> > > wrote: > > > > > 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 :) > > > > Hmm. I had the same reaction to these two as Jan, but assumed that they > > made applying later patches easier, and didn't take the trouble he did to > > find that's not so. > > > > I've no wish to be disputatious, but it does seem that the definition of > > "stable" has changed, and not necessarily for the better, if it's now a > > home for small gains: I thought we left those to upstream. > > This is in the SLES kernel for a reason, and again, it's in the section > that says "this should be pushed to stable". So if it's good enough for > the SLES kernel, why isn't it good enough for all users of this kernel > tree? Heh, fair enough. I guess Mel in the end didn't find patches worthy enough to be pushed to stable tree. But at least now I know they are well tested with 4.4 base so they should do no harm in the stable tree so my stance is closer to neutral. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
