On Sat, Apr 28, 2018 at 10:01:57AM +0000, Timofey Titovets wrote: > May be i misunderstood something, but i was think that slab combine > several pages in continuous range, so object in slab can cross page > boundary. So, all calculation will be very depends on scale of slab > size. > > i.e. on my machine that looks quite different: > name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> > btrfs_inode 142475 146272 1136 28 8 > > So, > PAGE_SIZE * pagesperslab / objperslab > 4096 * 8 / 28 = 1170.28 > > 4096*8 - 1136*28 = 960 > > That's looks like object can cross page boundary in slab. > So, if size reduced to 1128, > 4096 * 8 / 29 = 1129.93 > 4096*8 - 1128*29 = 56 > > Did i miss something? Then this depends on the allocator, SLAB does 4k pages and SLUB 32k, so there's a value in reducing the inode size. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
