Commit 859a85dd authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
Browse files

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: default avatarMike Rapoport <rppt@linux.ibm.com>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ac3332c4

drivers/base/node.c

+0 −2
Original line number Diff line number Diff line
@@ -768,8 +768,6 @@ int unregister_cpu_under_node(unsigned int cpu, unsigned int nid) 
#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE

static int __ref get_nid_for_pfn(unsigned long pfn)

{

	if (!pfn_valid_within(pfn))

		return -1;

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT

	if (system_state < SYSTEM_RUNNING)

		return early_pfn_to_nid(pfn);

include/linux/mmzone.h

+0 −12
Original line number Diff line number Diff line
@@ -1525,18 +1525,6 @@ void sparse_init(void); 
#define subsection_map_init(_pfn, _nr_pages) do {} while (0)

#endif /* CONFIG_SPARSEMEM */



/*

 * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we

 * need to check pfn validity within that MAX_ORDER_NR_PAGES block.

 * pfn_valid_within() should be used in this case; we optimise this away

 * when we have no holes within a MAX_ORDER_NR_PAGES block.

 */

#ifdef CONFIG_HOLES_IN_ZONE

#define pfn_valid_within(pfn) pfn_valid(pfn)

#else

#define pfn_valid_within(pfn) (1)

#endif



#endif /* !__GENERATING_BOUNDS.H */

#endif /* !__ASSEMBLY__ */

#endif /* _LINUX_MMZONE_H */

mm/Kconfig

+0 −3
Original line number Diff line number Diff line
@@ -96,9 +96,6 @@ config HAVE_FAST_GUP 
	depends on MMU

	bool



config HOLES_IN_ZONE

	bool



# Don't discard allocated memory used to track "memory" and "reserved" memblocks

# after early boot, so it can still be used to test for validity of memory.

# Also, memblocks are updated with memory hot(un)plug.

mm/compaction.c

+7 −13
Original line number Diff line number Diff line
@@ -306,7 +306,6 @@ __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;
@@ -316,7 +315,6 @@ __reset_isolation_pfn(struct zone *zone, unsigned long pfn, bool check_source, 
			clear_pageblock_skip(page);

			return true;

		}

		}



		page += (1 << PAGE_ALLOC_COSTLY_ORDER);

		pfn += (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);

mm/memory_hotplug.c

+0 −4
Original line number Diff line number Diff line
@@ -1308,10 +1308,6 @@ struct zone *test_pages_in_a_zone(unsigned long start_pfn, 
		for (; pfn < sec_end_pfn && pfn < end_pfn;

		     pfn += MAX_ORDER_NR_PAGES) {

			i = 0;

			/* This is just a CONFIG_HOLES_IN_ZONE check.*/

			while ((i < MAX_ORDER_NR_PAGES) &&

				!pfn_valid_within(pfn + i))

				i++;

			if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)

				continue;

			/* Check if we got outside of the zone */