On Thu, Oct 01, 2020 at 02:59:50PM -0400, Johannes Weiner wrote: > On Thu, Oct 01, 2020 at 11:27:39AM -0700, Roman Gushchin wrote: > > On Thu, Oct 01, 2020 at 09:46:38AM -0400, Johannes Weiner wrote: > > > On Wed, Sep 30, 2020 at 05:27:07PM -0700, Roman Gushchin wrote: > > > > +/* > > > > + * set_page_memcg - associate a page with a memory cgroup > > > > + * @page: a pointer to the page struct > > > > + * @memcg: a pointer to the memory cgroup > > > > + * > > > > + * Associates a page with a memory cgroup. > > > > + */ > > > > +static inline void set_page_memcg(struct page *page, struct mem_cgroup > > > > *memcg) > > > > +{ > > > > + VM_BUG_ON_PAGE(PageSlab(page), page); > > > > + > > > > + /* > > > > + * Please, refer to page_memcg()'s description for the page and > > > > memcg > > > > + * binding stability requirements. > > > > + */ > > > > + page->memcg_data = (unsigned long)memcg; > > > > +} > > > > > > Please delete and inline this as per previous feedback, thanks. > > > > Why it's better? > > It's ok for set_page_memcg(), but obviously worse for set_page_objcgs(): > > it was nice to have all bit magic in one place, in few helper functions. > > And now it spills into several places. What's the win? > > set_page_objcgs() is a worthwhile abstraction because it includes the > synchronization primitives that make it safe to use wrt > page_objcgs(). They encapsulate the cmpxchg and the READ_ONCE(). > > set_page_memcg() doesn't do any synchronization and relies fully on > the contextual locking. The name implies that it includes things to > make it safe wrt page_memcg(), which isn't true at all. It's a long > and misleading name for '='. > > Btw, I really don't mind having this discussion, but please don't send > revisions that silently ignore feedback you don't agree with.
I'm not ignoring: I thought you was looking to remove clear_page_* functions, but it wasn't clear you want eliminate set_page_memcg() function. Please, when you asking for some "style" changes, please, provide some rationale, it's way less obvious than you think, what exactly you don't like in the proposed version. Thanks.