Hi all,
On Fri, 3 Dec 2021 18:19:51 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> Today's linux-next merge of the akpm-current tree got a conflict in:
>
> mm/memcontrol.c
>
> between commit:
>
> eefa12e18a92 ("mm/memcg: Convert slab objcgs from struct page to struct slab")
>
> from the slab tree and commit:
>
> 93e959c235eb ("mm/memcg: relocate mod_objcg_mlstate(), get_obj_stock() and put_obj_stock()")
>
> from the akpm-current tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
> diff --cc mm/memcontrol.c
> index 522fff11d6d1,69d4fdafbb80..000000000000
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@@ -2816,10 -2769,63 +2769,63 @@@ retry
> */
> #define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT)
>
> + /*
> + * Most kmem_cache_alloc() calls are from user context. The irq disable/enable
> + * sequence used in this case to access content from object stock is slow.
> + * To optimize for user context access, there are now two object stocks for
> + * task context and interrupt context access respectively.
> + *
> + * The task context object stock can be accessed by disabling preemption only
> + * which is cheap in non-preempt kernel. The interrupt context object stock
> + * can only be accessed after disabling interrupt. User context code can
> + * access interrupt object stock, but not vice versa.
> + */
> + static inline struct obj_stock *get_obj_stock(unsigned long *pflags)
> + {
> + struct memcg_stock_pcp *stock;
> +
> + if (likely(in_task())) {
> + *pflags = 0UL;
> + preempt_disable();
> + stock = this_cpu_ptr(&memcg_stock);
> + return &stock->task_obj;
> + }
> +
> + local_irq_save(*pflags);
> + stock = this_cpu_ptr(&memcg_stock);
> + return &stock->irq_obj;
> + }
> +
> + static inline void put_obj_stock(unsigned long flags)
> + {
> + if (likely(in_task()))
> + preempt_enable();
> + else
> + local_irq_restore(flags);
> + }
> +
> + /*
> + * mod_objcg_mlstate() may be called with irq enabled, so
> + * mod_memcg_lruvec_state() should be used.
> + */
> + static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,
> + struct pglist_data *pgdat,
> + enum node_stat_item idx, int nr)
> + {
> + struct mem_cgroup *memcg;
> + struct lruvec *lruvec;
> +
> + rcu_read_lock();
> + memcg = obj_cgroup_memcg(objcg);
> + lruvec = mem_cgroup_lruvec(memcg, pgdat);
> + mod_memcg_lruvec_state(lruvec, idx, nr);
> + rcu_read_unlock();
> + }
> +
> -int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
> - gfp_t gfp, bool new_page)
> +int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
> + gfp_t gfp, bool new_slab)
> {
> - unsigned int objects = objs_per_slab_page(s, page);
> + unsigned int objects = objs_per_slab(s, slab);
> unsigned long memcg_data;
> void *vec;
>
This is now a conflict between the slab tree and Linus' tree.
--
Cheers,
Stephen Rothwell
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