(2012/08/09 22:01), Glauber Costa wrote: > When a process tries to allocate a page with the __GFP_KMEMCG flag, the > page allocator will call the corresponding memcg functions to validate > the allocation. Tasks in the root memcg can always proceed. > > To avoid adding markers to the page - and a kmem flag that would > necessarily follow, as much as doing page_cgroup lookups for no reason, > whoever is marking its allocations with __GFP_KMEMCG flag is responsible > for telling the page allocator that this is such an allocation at > free_pages() time. This is done by the invocation of > __free_accounted_pages() and free_accounted_pages(). > > Signed-off-by: Glauber Costa <[email protected]> > CC: Christoph Lameter <[email protected]> > CC: Pekka Enberg <[email protected]> > CC: Michal Hocko <[email protected]> > CC: Kamezawa Hiroyuki <[email protected]> > CC: Johannes Weiner <[email protected]> > CC: Suleiman Souhlal <[email protected]>
Ah, ok. free_accounted_page() seems good. Acked-by: KAMEZAWA Hiroyuki <[email protected]> I myself is okay with this. But... Because you add a new hook to alloc_pages(), please get Ack from Mel before requesting merge. Thanks, -Kame > --- > include/linux/gfp.h | 3 +++ > mm/page_alloc.c | 38 ++++++++++++++++++++++++++++++++++++++ > 2 files changed, 41 insertions(+) > > diff --git a/include/linux/gfp.h b/include/linux/gfp.h > index d8eae4d..029570f 100644 > --- a/include/linux/gfp.h > +++ b/include/linux/gfp.h > @@ -370,6 +370,9 @@ extern void free_pages(unsigned long addr, unsigned int > order); > extern void free_hot_cold_page(struct page *page, int cold); > extern void free_hot_cold_page_list(struct list_head *list, int cold); > > +extern void __free_accounted_pages(struct page *page, unsigned int order); > +extern void free_accounted_pages(unsigned long addr, unsigned int order); > + > #define __free_page(page) __free_pages((page), 0) > #define free_page(addr) free_pages((addr), 0) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index b956cec..da341dc 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2532,6 +2532,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int > order, > struct page *page = NULL; > int migratetype = allocflags_to_migratetype(gfp_mask); > unsigned int cpuset_mems_cookie; > + void *handle = NULL; > > gfp_mask &= gfp_allowed_mask; > > @@ -2543,6 +2544,13 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int > order, > return NULL; > > /* > + * Will only have any effect when __GFP_KMEMCG is set. > + * This is verified in the (always inline) callee > + */ > + if (!memcg_kmem_new_page(gfp_mask, &handle, order)) > + return NULL; > + > + /* > * Check the zones suitable for the gfp_mask contain at least one > * valid zone. It's possible to have an empty zonelist as a result > * of GFP_THISNODE and a memoryless node > @@ -2583,6 +2591,8 @@ out: > if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page)) > goto retry_cpuset; > > + memcg_kmem_commit_page(page, handle, order); > + > return page; > } > EXPORT_SYMBOL(__alloc_pages_nodemask); > @@ -2635,6 +2645,34 @@ void free_pages(unsigned long addr, unsigned int order) > > EXPORT_SYMBOL(free_pages); > > +/* > + * __free_accounted_pages and free_accounted_pages will free pages allocated > + * with __GFP_KMEMCG. > + * > + * Those pages are accounted to a particular memcg, embedded in the > + * corresponding page_cgroup. To avoid adding a hit in the allocator to > search > + * for that information only to find out that it is NULL for users who have > no > + * interest in that whatsoever, we provide these functions. > + * > + * The caller knows better which flags it relies on. > + */ > +void __free_accounted_pages(struct page *page, unsigned int order) > +{ > + memcg_kmem_free_page(page, order); > + __free_pages(page, order); > +} > +EXPORT_SYMBOL(__free_accounted_pages); > + > +void free_accounted_pages(unsigned long addr, unsigned int order) > +{ > + if (addr != 0) { > + VM_BUG_ON(!virt_addr_valid((void *)addr)); > + memcg_kmem_free_page(virt_to_page((void *)addr), order); > + __free_pages(virt_to_page((void *)addr), order); > + } > +} > +EXPORT_SYMBOL(free_accounted_pages); > + > static void *make_alloc_exact(unsigned long addr, unsigned order, size_t > size) > { > if (addr) { > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
