On Thu, Feb 15, 2024 at 10:10 PM Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote: > > On Thu, Feb 15, 2024 at 1:50 PM Vlastimil Babka <vbabka@xxxxxxx> wrote: > > > > On 2/15/24 22:37, Kent Overstreet wrote: > > > On Thu, Feb 15, 2024 at 10:31:06PM +0100, Vlastimil Babka wrote: > > >> On 2/12/24 22:38, Suren Baghdasaryan wrote: > > >> > Slab extension objects can't be allocated before slab infrastructure is > > >> > initialized. Some caches, like kmem_cache and kmem_cache_node, are created > > >> > before slab infrastructure is initialized. Objects from these caches can't > > >> > have extension objects. Introduce SLAB_NO_OBJ_EXT slab flag to mark these > > >> > caches and avoid creating extensions for objects allocated from these > > >> > slabs. > > >> > > > >> > Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> > > >> > --- > > >> > include/linux/slab.h | 7 +++++++ > > >> > mm/slub.c | 5 +++-- > > >> > 2 files changed, 10 insertions(+), 2 deletions(-) > > >> > > > >> > diff --git a/include/linux/slab.h b/include/linux/slab.h > > >> > index b5f5ee8308d0..3ac2fc830f0f 100644 > > >> > --- a/include/linux/slab.h > > >> > +++ b/include/linux/slab.h > > >> > @@ -164,6 +164,13 @@ > > >> > #endif > > >> > #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */ > > >> > > > >> > +#ifdef CONFIG_SLAB_OBJ_EXT > > >> > +/* Slab created using create_boot_cache */ > > >> > +#define SLAB_NO_OBJ_EXT ((slab_flags_t __force)0x20000000U) > > >> > > >> There's > > >> #define SLAB_SKIP_KFENCE ((slab_flags_t __force)0x20000000U) > > >> already, so need some other one? > > Indeed. I somehow missed it. Thanks for noticing, will fix this in the > next version. Apparently the only unused slab flag is 0x00000200U, all others seem to be taken. I'll use it if there are no objections. > > > > > > > What's up with the order of flags in that file? They don't seem to > > > follow any particular ordering. > > > > Seems mostly in increasing order, except commit 4fd0b46e89879 broke it for > > SLAB_RECLAIM_ACCOUNT? > > > > > Seems like some cleanup is in order, but any history/context we should > > > know first? > > > > Yeah noted, but no need to sidetrack you.
