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Commit 6b208e3f authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm: memcg: remove unused node/section info from pc->flags 



To find the page corresponding to a certain page_cgroup, the pc->flags
encoded the node or section ID with the base array to compare the pc
pointer to.

Now that the per-memory cgroup LRU lists link page descriptors directly,
there is no longer any code that knows the struct page_cgroup of a PFN
but not the struct page.

[hughd@google.com: remove unused node/section info from pc->flags fix]
Signed-off-by: default avatarJohannes Weiner <jweiner@redhat.com>
Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
Reviewed-by: default avatarKirill A. Shutemov <kirill@shutemov.name>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 925b7673

include/linux/page_cgroup.h

+0 −33
Original line number Diff line number Diff line
@@ -121,39 +121,6 @@ static inline void move_unlock_page_cgroup(struct page_cgroup *pc, 
	local_irq_restore(*flags);

}



#ifdef CONFIG_SPARSEMEM

#define PCG_ARRAYID_WIDTH	SECTIONS_SHIFT

#else

#define PCG_ARRAYID_WIDTH	NODES_SHIFT

#endif



#if (PCG_ARRAYID_WIDTH > BITS_PER_LONG - NR_PCG_FLAGS)

#error Not enough space left in pc->flags to store page_cgroup array IDs

#endif



/* pc->flags: ARRAY-ID | FLAGS */



#define PCG_ARRAYID_MASK	((1UL << PCG_ARRAYID_WIDTH) - 1)



#define PCG_ARRAYID_OFFSET	(BITS_PER_LONG - PCG_ARRAYID_WIDTH)

/*

 * Zero the shift count for non-existent fields, to prevent compiler

 * warnings and ensure references are optimized away.

 */

#define PCG_ARRAYID_SHIFT	(PCG_ARRAYID_OFFSET * (PCG_ARRAYID_WIDTH != 0))



static inline void set_page_cgroup_array_id(struct page_cgroup *pc,

					    unsigned long id)

{

	pc->flags &= ~(PCG_ARRAYID_MASK << PCG_ARRAYID_SHIFT);

	pc->flags |= (id & PCG_ARRAYID_MASK) << PCG_ARRAYID_SHIFT;

}



static inline unsigned long page_cgroup_array_id(struct page_cgroup *pc)

{

	return (pc->flags >> PCG_ARRAYID_SHIFT) & PCG_ARRAYID_MASK;

}



#else /* CONFIG_CGROUP_MEM_RES_CTLR */

struct page_cgroup;

mm/page_cgroup.c

+7 −52
Original line number Diff line number Diff line
@@ -11,12 +11,6 @@ 
#include <linux/swapops.h>

#include <linux/kmemleak.h>



static void __meminit init_page_cgroup(struct page_cgroup *pc, unsigned long id)

{

	pc->flags = 0;

	set_page_cgroup_array_id(pc, id);

	pc->mem_cgroup = NULL;

}

static unsigned long total_usage;



#if !defined(CONFIG_SPARSEMEM)
@@ -41,28 +35,13 @@ struct page_cgroup *lookup_page_cgroup(struct page *page) 
	return base + offset;

}



struct page *lookup_cgroup_page(struct page_cgroup *pc)

{

	unsigned long pfn;

	struct page *page;

	pg_data_t *pgdat;



	pgdat = NODE_DATA(page_cgroup_array_id(pc));

	pfn = pc - pgdat->node_page_cgroup + pgdat->node_start_pfn;

	page = pfn_to_page(pfn);

	VM_BUG_ON(pc != lookup_page_cgroup(page));

	return page;

}



static int __init alloc_node_page_cgroup(int nid)

{

	struct page_cgroup *base, *pc;

	struct page_cgroup *base;

	unsigned long table_size;

	unsigned long start_pfn, nr_pages, index;

	unsigned long nr_pages;



	start_pfn = NODE_DATA(nid)->node_start_pfn;

	nr_pages = NODE_DATA(nid)->node_spanned_pages;



	if (!nr_pages)

		return 0;
@@ -72,10 +51,6 @@ static int __init alloc_node_page_cgroup(int nid) 
			table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));

	if (!base)

		return -ENOMEM;

	for (index = 0; index < nr_pages; index++) {

		pc = base + index;

		init_page_cgroup(pc, nid);

	}

	NODE_DATA(nid)->node_page_cgroup = base;

	total_usage += table_size;

	return 0;
@@ -116,23 +91,10 @@ struct page_cgroup *lookup_page_cgroup(struct page *page) 
	return section->page_cgroup + pfn;

}



struct page *lookup_cgroup_page(struct page_cgroup *pc)

{

	struct mem_section *section;

	struct page *page;

	unsigned long nr;



	nr = page_cgroup_array_id(pc);

	section = __nr_to_section(nr);

	page = pfn_to_page(pc - section->page_cgroup);

	VM_BUG_ON(pc != lookup_page_cgroup(page));

	return page;

}



static void *__meminit alloc_page_cgroup(size_t size, int nid)

{

	gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;

	void *addr = NULL;

	gfp_t flags = GFP_KERNEL | __GFP_NOWARN;



	addr = alloc_pages_exact_nid(nid, size, flags);

	if (addr) {
@@ -141,9 +103,9 @@ static void *__meminit alloc_page_cgroup(size_t size, int nid) 
	}



	if (node_state(nid, N_HIGH_MEMORY))

		addr = vmalloc_node(size, nid);

		addr = vzalloc_node(size, nid);

	else

		addr = vmalloc(size);

		addr = vzalloc(size);



	return addr;

}
@@ -166,14 +128,11 @@ static void free_page_cgroup(void *addr) 


static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)

{

	struct page_cgroup *base, *pc;

	struct mem_section *section;

	struct page_cgroup *base;

	unsigned long table_size;

	unsigned long nr;

	int index;



	nr = pfn_to_section_nr(pfn);

	section = __nr_to_section(nr);

	section = __pfn_to_section(pfn);



	if (section->page_cgroup)

		return 0;
@@ -193,10 +152,6 @@ static int __meminit init_section_page_cgroup(unsigned long pfn, int nid) 
		return -ENOMEM;

	}



	for (index = 0; index < PAGES_PER_SECTION; index++) {

		pc = base + index;

		init_page_cgroup(pc, nr);

	}

	/*

	 * The passed "pfn" may not be aligned to SECTION.  For the calculation

	 * we need to apply a mask.