Hi Huge, On Tue, Aug 10, 2021 at 02:35:05PM -0700, Hugh Dickins wrote: > On Tue, 10 Aug 2021, Feng Tang wrote: > > On Mon, Aug 09, 2021 at 03:19:32PM +0200, Michal Hocko wrote: > > [snip] > > > > > Do you think you can provide same helpers for other policies as well? > > > > > Maybe we can get rid of some other ifdefery as well. > > > > > > > > Sure. I can make separate patch(es) for that. > > > > > > > > And you mean helper like mpol_is_bind/default/local/preferred? > > > > > > > > I just run 'git-grep MPOL', and for places using "mode == MPOL_XXX", > > > > mostly they are in mempolicy.[ch], the only another place is in > > > > shmem.c, do we need to create all the helpers for it and the > > > > potential future users? > > > > > > I would just go with those instances which need to ifdef for NUMA. > > > Thanks! > > > > Yes, following is a patch to remove one CONFIG_NUMA check, though > > an bolder idea to extend the patch by removing the CONFIG_TMPFS > > check in the same line. > > > > Thanks, > > Feng > > > > ---------8<--------------------------------- > > > > From 1a5858721ac8ce99c27c13d310bba2983dc73d97 Mon Sep 17 00:00:00 2001 > > From: Feng Tang <feng.tang@xxxxxxxxx> > > Date: Tue, 10 Aug 2021 17:00:59 +0800 > > Subject: [PATCH] mm: shmem: avoid open coded check for mempolicy's mode > > > > Add a mempolicy helper to do the check, which can also remove > > a CONFIG_NUMA option check. > > > > Suggested-by: Michal Hocko <mhocko@xxxxxxxx> > > Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx> > > No thanks: this is not an improvement. > > The "#if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)" is there to > eliminate dead code that would not be automatically eliminated by the > optimizer: it's not there just to avoid MPOL_DEFAULT, and it's there > to cover shmem_get_sbmpol() along with shmem_show_mpol(). Thanks for the explaination! I did some tests that in !NUMA case, the 'sbinfo->mpol' is always NULL (I could be wrong) which makes the 2 functions almost non-ops. > I know we tend to avoid #ifdefs in .c files, and that's good; and > I know you could find other code in mm/shmem.c which might also be > #ifdef'ed to eliminate other dead code in other configs; but unless > there's a new drive to purge our .c source of all #ifdefs, > please just leave this as is. Ok, and sorry for the noise. Thanks, Feng > Thanks, > Hugh >
