On 9/29/22 13:53, David Laight wrote: >> -static void rcu_free_slab(struct rcu_head *h) >> +/* >> + * rcu_free_slab() must be __aligned(4) because its address is saved >> + * in the rcu_head field, which coincides with page->mapping, which >> + * causes trouble if compaction mistakes it for PAGE_MAPPING_MOVABLE. >> + */ >> +__aligned(4) static void rcu_free_slab(struct rcu_head *h) >> { >> struct slab *slab = container_of(h, struct slab, rcu_head); >> > > Isn't that going to cause grief with options that align > functions on 16/32byte boundaries when adding space for > 'other stuff'? How is that done exactly? Also having higher alignment (16/32) is not in conflict with asking for 4? > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales) >