mm: remove pfn_valid_within() and CONFIG_HOLES_IN_ZONE

Patch series "mm: remove pfn_valid_within() and CONFIG_HOLES_IN_ZONE".

After recent updates to freeing unused parts of the memory map, no
architecture can have holes in the memory map within a pageblock.  This
makes pfn_valid_within() check and CONFIG_HOLES_IN_ZONE configuration
option redundant.

The first patch removes them both in a mechanical way and the second patch
simplifies memory_hotplug::test_pages_in_a_zone() that had
pfn_valid_within() surrounded by more logic than simple if.

This patch (of 2):

After recent changes in freeing of the unused parts of the memory map and
rework of pfn_valid() in arm and arm64 there are no architectures that can
have holes in the memory map within a pageblock and so nothing can enable
CONFIG_HOLES_IN_ZONE which guards non trivial implementation of
pfn_valid_within().

With that, pfn_valid_within() is always hardwired to 1 and can be
completely removed.

Remove calls to pfn_valid_within() and CONFIG_HOLES_IN_ZONE.

Link: https://lkml.kernel.org/r/20210713080035.7464-1-rppt@kernel.org
Link: https://lkml.kernel.org/r/20210713080035.7464-2-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 13 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 621508e0ecd5..ed37e1cb4369 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -306,16 +306,14 @@ __reset_isolation_pfn(struct zone *zone, unsigned long pfn, bool check_source,
 	 * is necessary for the block to be a migration source/target.
 	 */
 	do {
-		if (pfn_valid_within(pfn)) {
-			if (check_source && PageLRU(page)) {
-				clear_pageblock_skip(page);
-				return true;
-			}
+		if (check_source && PageLRU(page)) {
+			clear_pageblock_skip(page);
+			return true;
+		}
 
-			if (check_target && PageBuddy(page)) {
-				clear_pageblock_skip(page);
-				return true;
-			}
+		if (check_target && PageBuddy(page)) {
+			clear_pageblock_skip(page);
+			return true;
 		}
 
 		page += (1 << PAGE_ALLOC_COSTLY_ORDER);
@@ -585,8 +583,6 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 			break;
 
 		nr_scanned++;
-		if (!pfn_valid_within(blockpfn))
-			goto isolate_fail;
 
 		/*
 		 * For compound pages such as THP and hugetlbfs, we can save
@@ -885,8 +881,6 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 			cond_resched();
 		}
 
-		if (!pfn_valid_within(low_pfn))
-			goto isolate_fail;
 		nr_scanned++;
 
 		page = pfn_to_page(low_pfn);