On Wed, 4 Nov 2020 22:25:16 +0800 Hui Su <sh_def@xxxxxxx> wrote: > mem_cgroup_page_lruvec() in memcontrol.c and > mem_cgroup_lruvec() in memcontrol.h is very similar > except for the param(page and memcg) which also can be > convert to each other. > > So rewrite mem_cgroup_page_lruvec() with mem_cgroup_lruvec(). Alex Shi's "mm/memcg: warning on !memcg after readahead page charged" (https://lkml.kernel.org/r/1604283436-18880-3-git-send-email-alex.shi@xxxxxxxxxxxxxxxxx) changes mem_cgroup_page_lruvec() thusly: --- a/mm/memcontrol.c~mm-memcg-warning-on-memcg-after-readahead-page-charged +++ a/mm/memcontrol.c @@ -1325,10 +1325,7 @@ struct lruvec *mem_cgroup_page_lruvec(st } memcg = page_memcg(page); - /* - * Swapcache readahead pages are added to the LRU - and - * possibly migrated - before they are charged. - */ + VM_WARN_ON_ONCE_PAGE(!memcg, page); if (!memcg) memcg = root_mem_cgroup; So the patch didn't apply. That's easily fixed, but it does make one wonder whether this: > -struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *); > +/** > + * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page > + * @page: the page > + * @pgdat: pgdat of the page > + * > + * This function relies on page->mem_cgroup being stable. > + */ > +static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page, > + struct pglist_data *pgdat) > +{ > + struct mem_cgroup *memcg = page->mem_cgroup; > + > + return mem_cgroup_lruvec(memcg, pgdat); > +} Should be using page_memcg()?
