Commit 1a6d53a1 authored by Vlastimil Babka's avatar Vlastimil Babka Committed by Linus Torvalds
Browse files

mm: reduce try_to_compact_pages parameters 



Expand the usage of the struct alloc_context introduced in the previous
patch also for calling try_to_compact_pages(), to reduce the number of its
parameters.  Since the function is in different compilation unit, we need
to move alloc_context definition in the shared mm/internal.h header.

With this change we get simpler code and small savings of code size and stack
usage:

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-27 (-27)
function                                     old     new   delta
__alloc_pages_direct_compact                 283     256     -27
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-13 (-13)
function                                     old     new   delta
try_to_compact_pages                         582     569     -13

Stack usage of __alloc_pages_direct_compact goes from 24 to none (per
scripts/checkstack.pl).

Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a9263751

include/linux/compaction.h

+9 −8
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
/* Zone lock or lru_lock was contended in async compaction */

#define COMPACT_CONTENDED_LOCK	2



struct alloc_context; /* in mm/internal.h */



#ifdef CONFIG_COMPACTION

extern int sysctl_compact_memory;

extern int sysctl_compaction_handler(struct ctl_table *table, int write,
@@ -30,10 +32,9 @@ extern int sysctl_extfrag_handler(struct ctl_table *table, int write, 
			void __user *buffer, size_t *length, loff_t *ppos);



extern int fragmentation_index(struct zone *zone, unsigned int order);

extern unsigned long try_to_compact_pages(struct zonelist *zonelist,

			int order, gfp_t gfp_mask, nodemask_t *mask,

			enum migrate_mode mode, int *contended,

			int alloc_flags, int classzone_idx);

extern unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order,

			int alloc_flags, const struct alloc_context *ac,

			enum migrate_mode mode, int *contended);

extern void compact_pgdat(pg_data_t *pgdat, int order);

extern void reset_isolation_suitable(pg_data_t *pgdat);

extern unsigned long compaction_suitable(struct zone *zone, int order,
@@ -101,10 +102,10 @@ static inline bool compaction_restarting(struct zone *zone, int order) 
}



#else

static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,

			int order, gfp_t gfp_mask, nodemask_t *nodemask,

			enum migrate_mode mode, int *contended,

			int alloc_flags, int classzone_idx)

static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,

			unsigned int order, int alloc_flags,

			const struct alloc_context *ac,

			enum migrate_mode mode, int *contended)

{

	return COMPACT_CONTINUE;

}

mm/compaction.c

+11 −12
Original line number Diff line number Diff line
@@ -1335,22 +1335,20 @@ int sysctl_extfrag_threshold = 500; 


/**

 * try_to_compact_pages - Direct compact to satisfy a high-order allocation

 * @zonelist: The zonelist used for the current allocation

 * @order: The order of the current allocation

 * @gfp_mask: The GFP mask of the current allocation

 * @nodemask: The allowed nodes to allocate from

 * @order: The order of the current allocation

 * @alloc_flags: The allocation flags of the current allocation

 * @ac: The context of current allocation

 * @mode: The migration mode for async, sync light, or sync migration

 * @contended: Return value that determines if compaction was aborted due to

 *	       need_resched() or lock contention

 *

 * This is the main entry point for direct page compaction.

 */

unsigned long try_to_compact_pages(struct zonelist *zonelist,

			int order, gfp_t gfp_mask, nodemask_t *nodemask,

			enum migrate_mode mode, int *contended,

			int alloc_flags, int classzone_idx)

unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order,

			int alloc_flags, const struct alloc_context *ac,

			enum migrate_mode mode, int *contended)

{

	enum zone_type high_zoneidx = gfp_zone(gfp_mask);

	int may_enter_fs = gfp_mask & __GFP_FS;

	int may_perform_io = gfp_mask & __GFP_IO;

	struct zoneref *z;
@@ -1365,8 +1363,8 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist, 
		return COMPACT_SKIPPED;



	/* Compact each zone in the list */

	for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx,

								nodemask) {

	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,

								ac->nodemask) {

		int status;

		int zone_contended;
@@ -1374,7 +1372,8 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist, 
			continue;



		status = compact_zone_order(zone, order, gfp_mask, mode,

				&zone_contended, alloc_flags, classzone_idx);

				&zone_contended, alloc_flags,

				ac->classzone_idx);

		rc = max(status, rc);

		/*

		 * It takes at least one zone that wasn't lock contended
@@ -1384,7 +1383,7 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist, 


		/* If a normal allocation would succeed, stop compacting */

		if (zone_watermark_ok(zone, order, low_wmark_pages(zone),

					classzone_idx, alloc_flags)) {

					ac->classzone_idx, alloc_flags)) {

			/*

			 * We think the allocation will succeed in this zone,

			 * but it is not certain, hence the false. The caller

mm/internal.h

+22 −0
Original line number Diff line number Diff line
@@ -109,6 +109,28 @@ extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address); 
 * in mm/page_alloc.c

 */



/*

 * Structure for holding the mostly immutable allocation parameters passed

 * between functions involved in allocations, including the alloc_pages*

 * family of functions.

 *

 * nodemask, migratetype and high_zoneidx are initialized only once in

 * __alloc_pages_nodemask() and then never change.

 *

 * zonelist, preferred_zone and classzone_idx are set first in

 * __alloc_pages_nodemask() for the fast path, and might be later changed

 * in __alloc_pages_slowpath(). All other functions pass the whole strucure

 * by a const pointer.

 */

struct alloc_context {

	struct zonelist *zonelist;

	nodemask_t *nodemask;

	struct zone *preferred_zone;

	int classzone_idx;

	int migratetype;

	enum zone_type high_zoneidx;

};



/*

 * Locate the struct page for both the matching buddy in our

 * pair (buddy1) and the combined O(n+1) page they form (page).

mm/page_alloc.c

+2 −25
Original line number Diff line number Diff line
@@ -232,27 +232,6 @@ EXPORT_SYMBOL(nr_node_ids); 
EXPORT_SYMBOL(nr_online_nodes);

#endif



/*

 * Structure for holding the mostly immutable allocation parameters passed

 * between alloc_pages* family of functions.

 *

 * nodemask, migratetype and high_zoneidx are initialized only once in

 * __alloc_pages_nodemask() and then never change.

 *

 * zonelist, preferred_zone and classzone_idx are set first in

 * __alloc_pages_nodemask() for the fast path, and might be later changed

 * in __alloc_pages_slowpath(). All other functions pass the whole strucure

 * by a const pointer.

 */

struct alloc_context {

	struct zonelist *zonelist;

	nodemask_t *nodemask;

	struct zone *preferred_zone;

	int classzone_idx;

	int migratetype;

	enum zone_type high_zoneidx;

};



int page_group_by_mobility_disabled __read_mostly;



void set_pageblock_migratetype(struct page *page, int migratetype)
@@ -2429,10 +2408,8 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, 
		return NULL;



	current->flags |= PF_MEMALLOC;

	compact_result = try_to_compact_pages(ac->zonelist, order, gfp_mask,

						ac->nodemask, mode,

						contended_compaction,

						alloc_flags, ac->classzone_idx);

	compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,

						mode, contended_compaction);

	current->flags &= ~PF_MEMALLOC;



	switch (compact_result) {

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