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: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 12 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 546e571e9d60..9c7e6909dd29 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -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