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From:   js1304@gmail.com
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Vlastimil Babka <vbabka@suse.cz>, Michal Hocko <mhocko@suse.com>,
        Laura Abbott <lauraa@codeaurora.org>,
        =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= 
        <ville.syrjala@linux.intel.com>,
        LKML <linux-kernel@vger.kernel.org>, linux-mm@kvack.org,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: [PATCH] Revert "mm/cma: manage the memory of the CMA area by using the ZONE_MOVABLE"
Date:   Wed, 23 May 2018 10:18:21 +0900
Message-Id: <1527038301-24368-1-git-send-email-iamjoonsoo.kim@lge.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Joonsoo Kim <iamjoonsoo.kim@lge.com>

This reverts the following commits that change CMA design in MM.

Revert "ARM: CMA: avoid double mapping to the CMA area if CONFIG_HIGHMEM=y"
This reverts commit 3d2054ad8c2d5100b68b0c0405f89fd90bf4107b.

Revert "mm/cma: remove ALLOC_CMA"
This reverts commit 1d47a3ec09b5489cd915e8f492aa623cdab5d002.

Revert "mm/cma: manage the memory of the CMA area by using the ZONE_MOVABLE"
This reverts commit bad8c6c0b1144694ecb0bc5629ede9b8b578b86e.

Ville reported a following error on i386.

[    0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[    0.000000] microcode: microcode updated early to revision 0x4, date = 2013-06-28
[    0.000000] Initializing CPU#0
[    0.000000] Initializing HighMem for node 0 (000377fe:00118000)
[    0.000000] Initializing Movable for node 0 (00000001:00118000)
[    0.000000] BUG: Bad page state in process swapper  pfn:377fe
[    0.000000] page:f53effc0 count:0 mapcount:-127 mapping:00000000 index:0x0
[    0.000000] flags: 0x80000000()
[    0.000000] raw: 80000000 00000000 00000000 ffffff80 00000000 00000100 00000200 00000001
[    0.000000] page dumped because: nonzero mapcount
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.17.0-rc5-elk+ #145
[    0.000000] Hardware name: Dell Inc. Latitude E5410/03VXMC, BIOS A15 07/11/2013
[    0.000000] Call Trace:
[    0.000000]  dump_stack+0x60/0x96
[    0.000000]  bad_page+0x9a/0x100
[    0.000000]  free_pages_check_bad+0x3f/0x60
[    0.000000]  free_pcppages_bulk+0x29d/0x5b0
[    0.000000]  free_unref_page_commit+0x84/0xb0
[    0.000000]  free_unref_page+0x3e/0x70
[    0.000000]  __free_pages+0x1d/0x20
[    0.000000]  free_highmem_page+0x19/0x40
[    0.000000]  add_highpages_with_active_regions+0xab/0xeb
[    0.000000]  set_highmem_pages_init+0x66/0x73
[    0.000000]  mem_init+0x1b/0x1d7
[    0.000000]  start_kernel+0x17a/0x363
[    0.000000]  i386_start_kernel+0x95/0x99
[    0.000000]  startup_32_smp+0x164/0x168

Reason for this error is that the span of MOVABLE_ZONE is extended to
whole node span for future CMA initialization, and, normal memory is
wrongly freed here. I submitted the fix and it seems to work, but,
the other problem happened. It's so late time to fix the later problem
so I decide to reverting the series.

Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
---
 arch/arm/mm/dma-mapping.c      | 16 +-------
 include/linux/memory_hotplug.h |  3 ++
 include/linux/mm.h             |  1 -
 mm/cma.c                       | 83 ++++++------------------------------------
 mm/compaction.c                |  4 +-
 mm/internal.h                  |  4 +-
 mm/page_alloc.c                | 83 +++++++++++++++---------------------------
 7 files changed, 49 insertions(+), 145 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 8c398fe..ada8eb2 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -466,12 +466,6 @@ void __init dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
 void __init dma_contiguous_remap(void)
 {
 	int i;
-
-	if (!dma_mmu_remap_num)
-		return;
-
-	/* call flush_cache_all() since CMA area would be large enough */
-	flush_cache_all();
 	for (i = 0; i < dma_mmu_remap_num; i++) {
 		phys_addr_t start = dma_mmu_remap[i].base;
 		phys_addr_t end = start + dma_mmu_remap[i].size;
@@ -504,15 +498,7 @@ void __init dma_contiguous_remap(void)
 		flush_tlb_kernel_range(__phys_to_virt(start),
 				       __phys_to_virt(end));
 
-		/*
-		 * All the memory in CMA region will be on ZONE_MOVABLE.
-		 * If that zone is considered as highmem, the memory in CMA
-		 * region is also considered as highmem even if it's
-		 * physical address belong to lowmem. In this case,
-		 * re-mapping isn't required.
-		 */
-		if (!is_highmem_idx(ZONE_MOVABLE))
-			iotable_init(&map, 1);
+		iotable_init(&map, 1);
 	}
 }
 
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index e0e49b5..2b02652 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -216,6 +216,9 @@ void put_online_mems(void);
 void mem_hotplug_begin(void);
 void mem_hotplug_done(void);
 
+extern void set_zone_contiguous(struct zone *zone);
+extern void clear_zone_contiguous(struct zone *zone);
+
 #else /* ! CONFIG_MEMORY_HOTPLUG */
 #define pfn_to_online_page(pfn)			\
 ({						\
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c6fa9a2..02a616e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2109,7 +2109,6 @@ extern void setup_per_cpu_pageset(void);
 
 extern void zone_pcp_update(struct zone *zone);
 extern void zone_pcp_reset(struct zone *zone);
-extern void setup_zone_pageset(struct zone *zone);
 
 /* page_alloc.c */
 extern int min_free_kbytes;
diff --git a/mm/cma.c b/mm/cma.c
index aa40e6c..5809bbe 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -39,7 +39,6 @@
 #include <trace/events/cma.h>
 
 #include "cma.h"
-#include "internal.h"
 
 struct cma cma_areas[MAX_CMA_AREAS];
 unsigned cma_area_count;
@@ -110,25 +109,23 @@ static int __init cma_activate_area(struct cma *cma)
 	if (!cma->bitmap)
 		return -ENOMEM;
 
+	WARN_ON_ONCE(!pfn_valid(pfn));
+	zone = page_zone(pfn_to_page(pfn));
+
 	do {
 		unsigned j;
 
 		base_pfn = pfn;
-		if (!pfn_valid(base_pfn))
-			goto err;
-
-		zone = page_zone(pfn_to_page(base_pfn));
 		for (j = pageblock_nr_pages; j; --j, pfn++) {
-			if (!pfn_valid(pfn))
-				goto err;
-
+			WARN_ON_ONCE(!pfn_valid(pfn));
 			/*
-			 * In init_cma_reserved_pageblock(), present_pages
-			 * is adjusted with assumption that all pages in
-			 * the pageblock come from a single zone.
+			 * alloc_contig_range requires the pfn range
+			 * specified to be in the same zone. Make this
+			 * simple by forcing the entire CMA resv range
+			 * to be in the same zone.
 			 */
 			if (page_zone(pfn_to_page(pfn)) != zone)
-				goto err;
+				goto not_in_zone;
 		}
 		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
 	} while (--i);
@@ -142,7 +139,7 @@ static int __init cma_activate_area(struct cma *cma)
 
 	return 0;
 
-err:
+not_in_zone:
 	pr_err("CMA area %s could not be activated\n", cma->name);
 	kfree(cma->bitmap);
 	cma->count = 0;
@@ -152,41 +149,6 @@ static int __init cma_activate_area(struct cma *cma)
 static int __init cma_init_reserved_areas(void)
 {
 	int i;
-	struct zone *zone;
-	pg_data_t *pgdat;
-
-	if (!cma_area_count)
-		return 0;
-
-	for_each_online_pgdat(pgdat) {
-		unsigned long start_pfn = UINT_MAX, end_pfn = 0;
-
-		zone = &pgdat->node_zones[ZONE_MOVABLE];
-
-		/*
-		 * In this case, we cannot adjust the zone range
-		 * since it is now maximum node span and we don't
-		 * know original zone range.
-		 */
-		if (populated_zone(zone))
-			continue;
-
-		for (i = 0; i < cma_area_count; i++) {
-			if (pfn_to_nid(cma_areas[i].base_pfn) !=
-				pgdat->node_id)
-				continue;
-
-			start_pfn = min(start_pfn, cma_areas[i].base_pfn);
-			end_pfn = max(end_pfn, cma_areas[i].base_pfn +
-						cma_areas[i].count);
-		}
-
-		if (!end_pfn)
-			continue;
-
-		zone->zone_start_pfn = start_pfn;
-		zone->spanned_pages = end_pfn - start_pfn;
-	}
 
 	for (i = 0; i < cma_area_count; i++) {
 		int ret = cma_activate_area(&cma_areas[i]);
@@ -195,32 +157,9 @@ static int __init cma_init_reserved_areas(void)
 			return ret;
 	}
 
-	/*
-	 * Reserved pages for ZONE_MOVABLE are now activated and
-	 * this would change ZONE_MOVABLE's managed page counter and
-	 * the other zones' present counter. We need to re-calculate
-	 * various zone information that depends on this initialization.
-	 */
-	build_all_zonelists(NULL);
-	for_each_populated_zone(zone) {
-		if (zone_idx(zone) == ZONE_MOVABLE) {
-			zone_pcp_reset(zone);
-			setup_zone_pageset(zone);
-		} else
-			zone_pcp_update(zone);
-
-		set_zone_contiguous(zone);
-	}
-
-	/*
-	 * We need to re-init per zone wmark by calling
-	 * init_per_zone_wmark_min() but doesn't call here because it is
-	 * registered on core_initcall and it will be called later than us.
-	 */
-
 	return 0;
 }
-pure_initcall(cma_init_reserved_areas);
+core_initcall(cma_init_reserved_areas);
 
 /**
  * cma_init_reserved_mem() - create custom contiguous area from reserved memory
diff --git a/mm/compaction.c b/mm/compaction.c
index 028b721..29bd1df 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1450,12 +1450,14 @@ static enum compact_result __compaction_suitable(struct zone *zone, int order,
 	 * if compaction succeeds.
 	 * For costly orders, we require low watermark instead of min for
 	 * compaction to proceed to increase its chances.
+	 * ALLOC_CMA is used, as pages in CMA pageblocks are considered
+	 * suitable migration targets
 	 */
 	watermark = (order > PAGE_ALLOC_COSTLY_ORDER) ?
 				low_wmark_pages(zone) : min_wmark_pages(zone);
 	watermark += compact_gap(order);
 	if (!__zone_watermark_ok(zone, 0, watermark, classzone_idx,
-						0, wmark_target))
+						ALLOC_CMA, wmark_target))
 		return COMPACT_SKIPPED;
 
 	return COMPACT_CONTINUE;
diff --git a/mm/internal.h b/mm/internal.h
index 62d8c34..502d141 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -168,9 +168,6 @@ extern void post_alloc_hook(struct page *page, unsigned int order,
 					gfp_t gfp_flags);
 extern int user_min_free_kbytes;
 
-extern void set_zone_contiguous(struct zone *zone);
-extern void clear_zone_contiguous(struct zone *zone);
-
 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
 
 /*
@@ -498,6 +495,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 #define ALLOC_HARDER		0x10 /* try to alloc harder */
 #define ALLOC_HIGH		0x20 /* __GFP_HIGH set */
 #define ALLOC_CPUSET		0x40 /* check for correct cpuset */
+#define ALLOC_CMA		0x80 /* allow allocations from CMA areas */
 
 enum ttu_flags;
 struct tlbflush_unmap_batch;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 905db9d..511a712 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1743,38 +1743,16 @@ void __init page_alloc_init_late(void)
 }
 
 #ifdef CONFIG_CMA
-static void __init adjust_present_page_count(struct page *page, long count)
-{
-	struct zone *zone = page_zone(page);
-
-	/* We don't need to hold a lock since it is boot-up process */
-	zone->present_pages += count;
-}
-
 /* Free whole pageblock and set its migration type to MIGRATE_CMA. */
 void __init init_cma_reserved_pageblock(struct page *page)
 {
 	unsigned i = pageblock_nr_pages;
-	unsigned long pfn = page_to_pfn(page);
 	struct page *p = page;
-	int nid = page_to_nid(page);
-
-	/*
-	 * ZONE_MOVABLE will steal present pages from other zones by
-	 * changing page links so page_zone() is changed. Before that,
-	 * we need to adjust previous zone's page count first.
-	 */
-	adjust_present_page_count(page, -pageblock_nr_pages);
 
 	do {
 		__ClearPageReserved(p);
 		set_page_count(p, 0);
-
-		/* Steal pages from other zones */
-		set_page_links(p, ZONE_MOVABLE, nid, pfn);
-	} while (++p, ++pfn, --i);
-
-	adjust_present_page_count(page, pageblock_nr_pages);
+	} while (++p, --i);
 
 	set_pageblock_migratetype(page, MIGRATE_CMA);
 
@@ -2889,7 +2867,7 @@ int __isolate_free_page(struct page *page, unsigned int order)
 		 * exists.
 		 */
 		watermark = min_wmark_pages(zone) + (1UL << order);
-		if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
+		if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
 			return 0;
 
 		__mod_zone_freepage_state(zone, -(1UL << order), mt);
@@ -3165,6 +3143,12 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
 	}
 
 
+#ifdef CONFIG_CMA
+	/* If allocation can't use CMA areas don't use free CMA pages */
+	if (!(alloc_flags & ALLOC_CMA))
+		free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
+#endif
+
 	/*
 	 * Check watermarks for an order-0 allocation request. If these
 	 * are not met, then a high-order request also cannot go ahead
@@ -3191,8 +3175,10 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
 		}
 
 #ifdef CONFIG_CMA
-		if (!list_empty(&area->free_list[MIGRATE_CMA]))
+		if ((alloc_flags & ALLOC_CMA) &&
+		    !list_empty(&area->free_list[MIGRATE_CMA])) {
 			return true;
+		}
 #endif
 		if (alloc_harder &&
 			!list_empty(&area->free_list[MIGRATE_HIGHATOMIC]))
@@ -3212,6 +3198,13 @@ static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
 		unsigned long mark, int classzone_idx, unsigned int alloc_flags)
 {
 	long free_pages = zone_page_state(z, NR_FREE_PAGES);
+	long cma_pages = 0;
+
+#ifdef CONFIG_CMA
+	/* If allocation can't use CMA areas don't use free CMA pages */
+	if (!(alloc_flags & ALLOC_CMA))
+		cma_pages = zone_page_state(z, NR_FREE_CMA_PAGES);
+#endif
 
 	/*
 	 * Fast check for order-0 only. If this fails then the reserves
@@ -3220,7 +3213,7 @@ static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
 	 * the caller is !atomic then it'll uselessly search the free
 	 * list. That corner case is then slower but it is harmless.
 	 */
-	if (!order && free_pages > mark + z->lowmem_reserve[classzone_idx])
+	if (!order && (free_pages - cma_pages) > mark + z->lowmem_reserve[classzone_idx])
 		return true;
 
 	return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
@@ -3856,6 +3849,10 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
 	} else if (unlikely(rt_task(current)) && !in_interrupt())
 		alloc_flags |= ALLOC_HARDER;
 
+#ifdef CONFIG_CMA
+	if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
+		alloc_flags |= ALLOC_CMA;
+#endif
 	return alloc_flags;
 }
 
@@ -4322,6 +4319,9 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
 	if (should_fail_alloc_page(gfp_mask, order))
 		return false;
 
+	if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE)
+		*alloc_flags |= ALLOC_CMA;
+
 	return true;
 }
 
@@ -6204,7 +6204,6 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
 {
 	enum zone_type j;
 	int nid = pgdat->node_id;
-	unsigned long node_end_pfn = 0;
 
 	pgdat_resize_init(pgdat);
 #ifdef CONFIG_NUMA_BALANCING
@@ -6232,13 +6231,9 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
 		struct zone *zone = pgdat->node_zones + j;
 		unsigned long size, realsize, freesize, memmap_pages;
 		unsigned long zone_start_pfn = zone->zone_start_pfn;
-		unsigned long movable_size = 0;
 
 		size = zone->spanned_pages;
 		realsize = freesize = zone->present_pages;
-		if (zone_end_pfn(zone) > node_end_pfn)
-			node_end_pfn = zone_end_pfn(zone);
-
 
 		/*
 		 * Adjust freesize so that it accounts for how much memory
@@ -6287,30 +6282,12 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
 		zone_seqlock_init(zone);
 		zone_pcp_init(zone);
 
-		/*
-		 * The size of the CMA area is unknown now so we need to
-		 * prepare the memory for the usemap at maximum.
-		 */
-		if (IS_ENABLED(CONFIG_CMA) && j == ZONE_MOVABLE &&
-			pgdat->node_spanned_pages) {
-			movable_size = node_end_pfn - pgdat->node_start_pfn;
-		}
-
-		if (!size && !movable_size)
+		if (!size)
 			continue;
 
 		set_pageblock_order();
-		if (movable_size) {
-			zone->zone_start_pfn = pgdat->node_start_pfn;
-			zone->spanned_pages = movable_size;
-			setup_usemap(pgdat, zone,
-				pgdat->node_start_pfn, movable_size);
-			init_currently_empty_zone(zone,
-				pgdat->node_start_pfn, movable_size);
-		} else {
-			setup_usemap(pgdat, zone, zone_start_pfn, size);
-			init_currently_empty_zone(zone, zone_start_pfn, size);
-		}
+		setup_usemap(pgdat, zone, zone_start_pfn, size);
+		init_currently_empty_zone(zone, zone_start_pfn, size);
 		memmap_init(size, nid, j, zone_start_pfn);
 	}
 }
@@ -7951,7 +7928,7 @@ void free_contig_range(unsigned long pfn, unsigned nr_pages)
 }
 #endif
 
-#if defined CONFIG_MEMORY_HOTPLUG || defined CONFIG_CMA
+#ifdef CONFIG_MEMORY_HOTPLUG
 /*
  * The zone indicated has a new number of managed_pages; batch sizes and percpu
  * page high values need to be recalulated.
-- 
2.7.4