On Tue, 9 Feb 2021 16:11:23 +0100 David Sterba <dsterba@xxxxxxx> wrote: > On Fri, Feb 05, 2021 at 03:23:00PM -0800, ira.weiny@xxxxxxxxx wrote: > > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > > > There are many places where kmap/<operation>/kunmap patterns occur. We lift > > these various patterns to core common functions and use them in the btrfs file > > system. At the same time we convert those core functions to use > > kmap_local_page() which is more efficient in those calls. > > > > I think this is best accepted through Andrew's tree as it has the mem*_page > > functions in it. But I'd like to get an ack from David or one of the other > > btrfs maintainers before the btrfs patches go through. > > I'd rather take the non-mm patches through my tree so it gets tested > the same way as other btrfs changes, straightforward cleanups or not. > > This brings the question how to do that as the first patch should go > through the MM tree. One option is to posptpone the actual cleanups > after the 1st patch is merged but this could take a long delay. > > I'd suggest to take the 1st patch within MM tree in the upcoming merge > window and then I can prepare a separate pull with just the cleanups. > Removing an inter-tree patch dependency was a sufficient reason for > Linus in the past for such pull requests. It would be best to merge [1/4] via the btrfs tree. Please add my Acked-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Although I think it would be better if [1/4] merely did the code movement. Adding those BUG_ON()s is a semantic/functional change and really shouldn't be bound up with the other things this patch series does. This logically separate change raises questions such as - What is the impact on overall code size? Not huge, presumably, but every little bit hurts. - Additional runtime costs of those extra comparisons? - These impacts could be lessened by using VM_BUG_ON() rather than BUG_ON() - should we do this? - Linus reeeeeeeally doesn't like new BUG_ON()s. Maybe you can sneak it past him ;) See what I mean? I do think it would be best to take those assertions out of the patch and to propose them separately, at a later time.
