(2013/03/05 22:10), Glauber Costa wrote:
> If we are not using memcg, there is no reason why we should allocate
> this structure, that will be a memory waste at best. We can do better
> at least in the sparsemem case, and allocate it when the first cgroup
> is requested. It should now not panic on failure, and we have to handle
> this right.
>
> flatmem case is a bit more complicated, so that one is left out for
> the moment.
>
> Signed-off-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
> CC: Michal Hocko <mhocko@xxxxxxx>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> CC: Johannes Weiner <hannes@xxxxxxxxxxx>
> CC: Mel Gorman <mgorman@xxxxxxx>
> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
> include/linux/page_cgroup.h | 28 +++++----
> init/main.c | 2 -
> mm/memcontrol.c | 3 +-
> mm/page_cgroup.c | 150 ++++++++++++++++++++++++--------------------
> 4 files changed, 99 insertions(+), 84 deletions(-)
This patch seems a complicated mixture of clean-up and what-you-really-want.
>
> diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
> index 777a524..ec9fb05 100644
> --- a/include/linux/page_cgroup.h
> +++ b/include/linux/page_cgroup.h
> @@ -14,6 +14,7 @@ enum {
>
> #ifdef CONFIG_MEMCG
> #include <linux/bit_spinlock.h>
> +#include <linux/mmzone.h>
>
> /*
> * Page Cgroup can be considered as an extended mem_map.
> @@ -27,19 +28,17 @@ struct page_cgroup {
> struct mem_cgroup *mem_cgroup;
> };
>
> -void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat);
> -
> -#ifdef CONFIG_SPARSEMEM
> -static inline void __init page_cgroup_init_flatmem(void)
> +static inline size_t page_cgroup_table_size(int nid)
> {
> -}
> -extern void __init page_cgroup_init(void);
> +#ifdef CONFIG_SPARSEMEM
> + return sizeof(struct page_cgroup) * PAGES_PER_SECTION;
> #else
> -void __init page_cgroup_init_flatmem(void);
> -static inline void __init page_cgroup_init(void)
> -{
> -}
> + return sizeof(struct page_cgroup) * NODE_DATA(nid)->node_spanned_pages;
> #endif
> +}
> +void pgdat_page_cgroup_init(struct pglist_data *pgdat);
> +
> +extern int page_cgroup_init(void);
>
> struct page_cgroup *lookup_page_cgroup(struct page *page);
> struct page *lookup_cgroup_page(struct page_cgroup *pc);
> @@ -85,7 +84,7 @@ static inline void unlock_page_cgroup(struct page_cgroup *pc)
> #else /* CONFIG_MEMCG */
> struct page_cgroup;
>
> -static inline void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
> +static inline void pgdat_page_cgroup_init(struct pglist_data *pgdat)
> {
> }
>
> @@ -94,7 +93,12 @@ static inline struct page_cgroup *lookup_page_cgroup(struct page *page)
> return NULL;
> }
>
> -static inline void page_cgroup_init(void)
> +static inline int page_cgroup_init(void)
> +{
> + return 0;
> +}
> +
> +static inline void page_cgroup_destroy(void)
> {
> }
>
> diff --git a/init/main.c b/init/main.c
> index cee4b5c..1fb3ec0 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -457,7 +457,6 @@ static void __init mm_init(void)
> * page_cgroup requires contiguous pages,
> * bigger than MAX_ORDER unless SPARSEMEM.
> */
> - page_cgroup_init_flatmem();
> mem_init();
> kmem_cache_init();
> percpu_init_late();
> @@ -592,7 +591,6 @@ asmlinkage void __init start_kernel(void)
> initrd_start = 0;
> }
> #endif
> - page_cgroup_init();
> debug_objects_mem_init();
> kmemleak_init();
> setup_per_cpu_pageset();
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 45c1886..6019a32 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -6377,7 +6377,8 @@ mem_cgroup_css_alloc(struct cgroup *cont)
> res_counter_init(&memcg->res, NULL);
> res_counter_init(&memcg->memsw, NULL);
> res_counter_init(&memcg->kmem, NULL);
> - }
> + } else if (page_cgroup_init())
> + goto free_out;
>
> memcg->last_scanned_node = MAX_NUMNODES;
> INIT_LIST_HEAD(&memcg->oom_notify);
> diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
> index a5bd322..6d04c28 100644
> --- a/mm/page_cgroup.c
> +++ b/mm/page_cgroup.c
> @@ -12,11 +12,50 @@
> #include <linux/kmemleak.h>
>
> static unsigned long total_usage;
> +static unsigned long page_cgroup_initialized;
>
> -#if !defined(CONFIG_SPARSEMEM)
> +static void *alloc_page_cgroup(size_t size, int nid)
> +{
> + gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
> + void *addr = NULL;
> +
> + addr = alloc_pages_exact_nid(nid, size, flags);
> + if (addr) {
> + kmemleak_alloc(addr, size, 1, flags);
> + return addr;
> + }
As far as I remember, this function was written for SPARSEMEM.
How big this "size" will be with FLATMEM/DISCONTIGMEM ?
if 16GB, 16 * 1024 * 1024 * 1024 / 4096 * 16 = 64MB.
What happens if order > MAX_ORDER is passed to alloc_pages()...no warning ?
How about using vmalloc always if not SPARSEMEM ?
> +
> + if (node_state(nid, N_HIGH_MEMORY))
> + addr = vzalloc_node(size, nid);
> + else
> + addr = vzalloc(size);
>
> + return addr;
> +}
>
> -void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
> +static void free_page_cgroup(void *addr)
> +{
> + if (is_vmalloc_addr(addr)) {
> + vfree(addr);
> + } else {
> + struct page *page = virt_to_page(addr);
> + int nid = page_to_nid(page);
> + BUG_ON(PageReserved(page));
This BUG_ON() can be removed.
> + free_pages_exact(addr, page_cgroup_table_size(nid));
> + }
> +}
> +
> +static void page_cgroup_msg(void)
> +{
> + printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
> + printk(KERN_INFO "please try 'cgroup_disable=memory' option if you "
> + "don't want memory cgroups.\nAlternatively, consider "
> + "deferring your memory cgroups creation.\n");
> +}
I think this warning can be removed because it's not boot option problem
after this patch. I guess the boot option can be obsolete....
> +
> +#if !defined(CONFIG_SPARSEMEM)
> +
> +void pgdat_page_cgroup_init(struct pglist_data *pgdat)
> {
> pgdat->node_page_cgroup = NULL;
> }
> @@ -42,20 +81,16 @@ struct page_cgroup *lookup_page_cgroup(struct page *page)
> return base + offset;
> }
>
> -static int __init alloc_node_page_cgroup(int nid)
> +static int alloc_node_page_cgroup(int nid)
> {
> struct page_cgroup *base;
> unsigned long table_size;
> - unsigned long nr_pages;
>
> - nr_pages = NODE_DATA(nid)->node_spanned_pages;
> - if (!nr_pages)
> + table_size = page_cgroup_table_size(nid);
> + if (!table_size)
> return 0;
>
> - table_size = sizeof(struct page_cgroup) * nr_pages;
> -
> - base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
> - table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
> + base = alloc_page_cgroup(table_size, nid);
> if (!base)
> return -ENOMEM;
> NODE_DATA(nid)->node_page_cgroup = base;
> @@ -63,27 +98,29 @@ static int __init alloc_node_page_cgroup(int nid)
> return 0;
> }
>
> -void __init page_cgroup_init_flatmem(void)
> +int page_cgroup_init(void)
> {
> + int nid, fail, tmpnid;
>
> - int nid, fail;
> -
> - if (mem_cgroup_subsys_disabled())
> - return;
> + /* only initialize it once */
> + if (test_and_set_bit(0, &page_cgroup_initialized))
> + return 0;
>
> for_each_online_node(nid) {
> fail = alloc_node_page_cgroup(nid);
> if (fail)
> goto fail;
> }
> - printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
> - printk(KERN_INFO "please try 'cgroup_disable=memory' option if you"
> - " don't want memory cgroups\n");
> - return;
> + page_cgroup_msg();
> + return 0;
> fail:
> - printk(KERN_CRIT "allocation of page_cgroup failed.\n");
> - printk(KERN_CRIT "please try 'cgroup_disable=memory' boot option\n");
> - panic("Out of memory");
> + for_each_online_node(tmpnid) {
> + if (tmpnid >= nid)
> + break;
> + free_page_cgroup(NODE_DATA(tmpnid)->node_page_cgroup);
> + }
> +
> + return -ENOMEM;
> }
>
> #else /* CONFIG_FLAT_NODE_MEM_MAP */
> @@ -105,26 +142,7 @@ struct page_cgroup *lookup_page_cgroup(struct page *page)
> return section->page_cgroup + pfn;
> }
>
> -static void *__meminit alloc_page_cgroup(size_t size, int nid)
> -{
> - gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
> - void *addr = NULL;
> -
> - addr = alloc_pages_exact_nid(nid, size, flags);
> - if (addr) {
> - kmemleak_alloc(addr, size, 1, flags);
> - return addr;
> - }
> -
> - if (node_state(nid, N_HIGH_MEMORY))
> - addr = vzalloc_node(size, nid);
> - else
> - addr = vzalloc(size);
> -
> - return addr;
> -}
> -
> -static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
> +static int init_section_page_cgroup(unsigned long pfn, int nid)
> {
> struct mem_section *section;
> struct page_cgroup *base;
> @@ -135,7 +153,7 @@ static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
> if (section->page_cgroup)
> return 0;
>
> - table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
> + table_size = page_cgroup_table_size(nid);
> base = alloc_page_cgroup(table_size, nid);
>
> /*
> @@ -159,20 +177,6 @@ static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
> total_usage += table_size;
> return 0;
> }
> -#ifdef CONFIG_MEMORY_HOTPLUG
> -static void free_page_cgroup(void *addr)
> -{
> - if (is_vmalloc_addr(addr)) {
> - vfree(addr);
> - } else {
> - struct page *page = virt_to_page(addr);
> - size_t table_size =
> - sizeof(struct page_cgroup) * PAGES_PER_SECTION;
> -
> - BUG_ON(PageReserved(page));
> - free_pages_exact(addr, table_size);
> - }
> -}
>
> void __free_page_cgroup(unsigned long pfn)
> {
> @@ -187,6 +191,7 @@ void __free_page_cgroup(unsigned long pfn)
> ms->page_cgroup = NULL;
> }
>
> +#ifdef CONFIG_MEMORY_HOTPLUG
> int __meminit online_page_cgroup(unsigned long start_pfn,
> unsigned long nr_pages,
> int nid)
> @@ -266,16 +271,16 @@ static int __meminit page_cgroup_callback(struct notifier_block *self,
>
> #endif
>
> -void __init page_cgroup_init(void)
> +int page_cgroup_init(void)
> {
> unsigned long pfn;
> - int nid;
> + unsigned long start_pfn, end_pfn;
> + int nid, tmpnid;
>
> - if (mem_cgroup_subsys_disabled())
> - return;
> + if (test_and_set_bit(0, &page_cgroup_initialized))
> + return 0;
>
> for_each_node_state(nid, N_MEMORY) {
> - unsigned long start_pfn, end_pfn;
>
> start_pfn = node_start_pfn(nid);
> end_pfn = node_end_pfn(nid);
> @@ -303,16 +308,23 @@ void __init page_cgroup_init(void)
> }
> }
> hotplug_memory_notifier(page_cgroup_callback, 0);
> - printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
> - printk(KERN_INFO "please try 'cgroup_disable=memory' option if you "
> - "don't want memory cgroups\n");
> - return;
> + page_cgroup_msg();
> + return 0;
> oom:
> - printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
> - panic("Out of memory");
> + for_each_node_state(tmpnid, N_MEMORY) {
> + if (tmpnid >= nid)
> + break;
> +
> + start_pfn = node_start_pfn(tmpnid);
> + end_pfn = node_end_pfn(tmpnid);
> +
> + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION)
> + __free_page_cgroup(pfn);
> + }
> + return -ENOMEM;
> }
>
> -void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
> +void pgdat_page_cgroup_init(struct pglist_data *pgdat)
> {
> return;
> }
>
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