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owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Jun 14, 2025 at 02:47:18AM +0900, Harry Yoo wrote: > On Fri, Jun 13, 2025 at 09:04:34AM -0700, Christoph Lameter (Ampere) wrote: > > On Fri, 13 Jun 2025, Harry Yoo wrote: > > > > > Allocate slabobj_exts array from this unused space instead of using > > > kcalloc(), when it is large enough. > > > > How does slab debug work in this case? The object layout gets a bit > > complicated with other metadata there as well. > > Oh, the 'leftover' space I mentioned the cover letter refers to the > wasted space after the last object in a slab, not unused bytes within > objects. > > There is no per-object metadata stored there and SLUB simply poisons the area. > I taught slab_pad_check() to skip checking the slabobj_exts array. Actually, it might be worth considering placing it within object in case the object is exactly a power-of-two size but has some wasted bytes due to alignment. xfs_inode seems to be a good candidate that could benefit from this. Hopefully it doesn't introduce too much complexity... -- Cheers, Harry / Hyeonggon