On Tue, Oct 06, 2026 at 02:20:26AM -0700, Kees Cook wrote: > Hi! Hi Kees!
Was hoping to say hi to you at LPC but I missed the chance ;) Maybe next time. Safe travels! Uh, my mailbox stopped working for a few days as I forgot to renew subscription. (Kiryl told me it's bouncing, thanks!) Hopefully I didn't miss too much... > This gets the buckets able to handle memcg (GFP_KERNEL_ACCOUNT) with > isolation (since it's common due to AF_UNIX), Cool! > and GFP_DMA with fall back > (since it's rare). > It gave me an excuse to build out bucket kunit tests > too, and that (and LLM review) found a couple other issues that needed > fixing too, including msg_msg allocations going uncharged to their memcg > when CONFIG_SLAB_BUCKETS=n (fixed in 2/8). Oh. > Harry, on your v4 question[1] about bucket users giving their own > alignment: I tried that in v5, but a set's allocations don't always > come from its own caches. With CONFIG_SLAB_BUCKETS=n, after a failed > kmem_buckets_create(), and for the DMA and reclaimable fallbacks, they > come from the general kmalloc caches, which can only give kmalloc()'s > alignment. > > So v6 goes back to mirroring the kmalloc cache's alignment, I might be missing something, but why is that a problem? For kmem_buckets users, the reason* to specify alignment is because they might need less strict alignment than kmalloc. (*Perhaps it's nice to document that in the comment) However, because kmem_buckets can fall back to kmalloc on e.g. kernels w/o CONFIG_SLAB_BUCKETS, it should be fine to fall back. No? Creating kmem_buckets with more strict alignment than kmalloc doesn't make sense. > and drops the ctor and flags arguments for the same reason. Uh, for ctor and flags, yes. We can't have them in kmem_buckets. > And the whole > exploration made me realize I had a completely wrong understanding of > how memcg worked. :P > > The bulk of this is mm/slab, but the final patch is netdev, which Paolo > acked in v4, so I'm hoping this whole series can go via slab? Going thorough slab/for-next sounds reasonable to me once it gets some reviews. Vlastimil? -- Cheers, Harry / Hyeonggon
