Messages in this thread | | | Date | Fri, 29 Jan 2016 11:43:53 -0500 | From | Johannes Weiner <> | Subject | Re: [PATCH 1/5] mm: memcontrol: generalize locking for the page->mem_cgroup binding |
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On Wed, Jan 27, 2016 at 05:30:45PM +0300, Vladimir Davydov wrote: > On Tue, Jan 26, 2016 at 04:00:02PM -0500, Johannes Weiner wrote: > > > @@ -683,17 +683,17 @@ int __set_page_dirty_buffers(struct page *page) > > } while (bh != head); > > } > > /* > > - * Use mem_group_begin_page_stat() to keep PageDirty synchronized with > > - * per-memcg dirty page counters. > > + * Lock out page->mem_cgroup migration to keep PageDirty > > + * synchronized with per-memcg dirty page counters. > > */ > > - memcg = mem_cgroup_begin_page_stat(page); > > + memcg = lock_page_memcg(page); > > newly_dirty = !TestSetPageDirty(page); > > spin_unlock(&mapping->private_lock); > > > > if (newly_dirty) > > __set_page_dirty(page, mapping, memcg, 1); > > Do we really want to pass memcg to __set_page_dirty and then to > account_page_dirtied, increasing stack/regs usage even in case memory > cgroup is disabled? May be, it'd be better to make > mem_cgroup_update_page_stat take a page instead of a memcg?
I'll look into that. It will need changing migration to leave the page->mem_cgroup binding of live pages alone, but that's something worth doing anyway. It's beyond the scope of these patches, though.
Thanks
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