On Tue, Sep 21, 2021 at 10:03:49AM +0100, Christoph Hellwig wrote: > On Tue, Sep 21, 2021 at 09:06:35AM +1000, Dave Chinner wrote: > > On Fri, Sep 17, 2021 at 06:30:10PM -0700, Darrick J. Wong wrote: > > > From: Darrick J. Wong <djwong@xxxxxxxxxx> > > > > > > Replace the statically-sized btree cursor zone with dynamically sized > > > allocations so that we can reduce the memory overhead for per-AG bt > > > cursors while handling very tall btrees for rt metadata. > > > > Hmmmmm. We do a *lot* of btree cursor allocation and freeing under > > load. Keeping that in a single slab rather than using heap memory is > > a good idea for stuff like this for many reasons... > > Or rather a few slabs for the different kind of cursors. But otherwise > agreed. I think I prefer to let Chandan decide if there are going to be enough heavily fragmented files to warrant a second slab for maxlevels>9 files. We should probably be selective about which cursor maxheight we want to use depending on whether or not the file really needs it. --D
