On 2023/05/17 6:35, Hyeonggon Yoo wrote: > [Resending this email after noticing I did not reply-to-all] > > On Fri, May 12, 2023 at 7:11 PM Gong Ruiqi <gongruiqi1@xxxxxxxxxx> wrote: >> [...] > >>>> +#ifdef CONFIG_RANDOM_KMALLOC_CACHES >>>> +# define SLAB_RANDOMSLAB ((slab_flags_t __force)0x01000000U) >>>> +#else >>>> +# define SLAB_RANDOMSLAB 0 >>>> +#endif > > There is already the SLAB_KMALLOC flag that indicates if a cache is a > kmalloc cache. I think that would be enough for preventing merging > kmalloc caches? After digging into the code of slab merging (e.g. slab_unmergeable(), find_mergeable(), SLAB_NEVER_MERGE, SLAB_MERGE_SAME etc), I haven't found an existing mechanism that prevents normal kmalloc caches with SLAB_KMALLOC from being merged with other slab caches. Maybe I missed something? While SLAB_RANDOMSLAB, unlike SLAB_KMALLOC, is added into SLAB_NEVER_MERGE, which explicitly indicates the no-merge policy.
