Re: [PATCH] mm: fix a regression with HIGHMEM introduced by changeset 7f1290f2f2a4d

[Chris Clayton <chris2553@googlemail.com>]

On 11/15/12 19:24, Andrew Morton wrote:
> On Wed, 14 Nov 2012 22:52:03 +0800
> Jiang Liu <liuj97@gmail.com> wrote:
>
>> 	So how about totally reverting the changeset 7f1290f2f2a4d2c3f1b7ce8e87256e052ca23125
>> and I will post another version once I found a cleaner way?
>
> We do need to get this regression fixed and I guess that a
> straightforward revert is an acceptable way of doing that, for now.
>
>
> I queued the below, with a plan to send it to Linus next week.
>

I've applied this patch to v3.7-rc5-28-g79e979e and can confirm that it 
fixes the problem I had with my laptop failing to resume (by either 
freezing or rebooting) after a suspend to disk.

Tested-by: Chris Clayton <chris2553@googlemail.com>

>
> From: Andrew Morton <akpm@linux-foundation.org>
> Subject: revert "mm: fix-up zone present pages"
>
> Revert
>
> commit 7f1290f2f2a4d2c3f1b7ce8e87256e052ca23125
> Author:     Jianguo Wu <wujianguo@huawei.com>
> AuthorDate: Mon Oct 8 16:33:06 2012 -0700
> Commit:     Linus Torvalds <torvalds@linux-foundation.org>
> CommitDate: Tue Oct 9 16:22:54 2012 +0900
>
>      mm: fix-up zone present pages
>
>
> That patch tried to fix a issue when calculating zone->present_pages, but
> it caused a regression on 32bit systems with HIGHMEM.  With that
> changeset, reset_zone_present_pages() resets all zone->present_pages to
> zero, and fixup_zone_present_pages() is called to recalculate
> zone->present_pages when the boot allocator frees core memory pages into
> buddy allocator.  Because highmem pages are not freed by bootmem
> allocator, all highmem zones' present_pages becomes zero.
>
> Various options for improving the situation are being discussed but for
> now, let's return to the 3.6 code.
>
> Cc: Jianguo Wu <wujianguo@huawei.com>
> Cc: Jiang Liu <jiang.liu@huawei.com>
> Cc: Petr Tesarik <ptesarik@suse.cz>
> Cc: "Luck, Tony" <tony.luck@intel.com>
> Cc: Mel Gorman <mel@csn.ul.ie>
> Cc: Yinghai Lu <yinghai@kernel.org>
> Cc: Minchan Kim <minchan.kim@gmail.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: David Rientjes <rientjes@google.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>   arch/ia64/mm/init.c |    1 -
>   include/linux/mm.h  |    4 ----
>   mm/bootmem.c        |   10 +---------
>   mm/memory_hotplug.c |    7 -------
>   mm/nobootmem.c      |    3 ---
>   mm/page_alloc.c     |   34 ----------------------------------
>   6 files changed, 1 insertion(+), 58 deletions(-)
>
> diff -puN arch/ia64/mm/init.c~revert-1 arch/ia64/mm/init.c
> --- a/arch/ia64/mm/init.c~revert-1
> +++ a/arch/ia64/mm/init.c
> @@ -637,7 +637,6 @@ mem_init (void)
>
>   	high_memory = __va(max_low_pfn * PAGE_SIZE);
>
> -	reset_zone_present_pages();
>   	for_each_online_pgdat(pgdat)
>   		if (pgdat->bdata->node_bootmem_map)
>   			totalram_pages += free_all_bootmem_node(pgdat);
> diff -puN include/linux/mm.h~revert-1 include/linux/mm.h
> --- a/include/linux/mm.h~revert-1
> +++ a/include/linux/mm.h
> @@ -1684,9 +1684,5 @@ static inline unsigned int debug_guardpa
>   static inline bool page_is_guard(struct page *page) { return false; }
>   #endif /* CONFIG_DEBUG_PAGEALLOC */
>
> -extern void reset_zone_present_pages(void);
> -extern void fixup_zone_present_pages(int nid, unsigned long start_pfn,
> -				unsigned long end_pfn);
> -
>   #endif /* __KERNEL__ */
>   #endif /* _LINUX_MM_H */
> diff -puN mm/bootmem.c~revert-1 mm/bootmem.c
> --- a/mm/bootmem.c~revert-1
> +++ a/mm/bootmem.c
> @@ -198,8 +198,6 @@ static unsigned long __init free_all_boo
>   			int order = ilog2(BITS_PER_LONG);
>
>   			__free_pages_bootmem(pfn_to_page(start), order);
> -			fixup_zone_present_pages(page_to_nid(pfn_to_page(start)),
> -					start, start + BITS_PER_LONG);
>   			count += BITS_PER_LONG;
>   			start += BITS_PER_LONG;
>   		} else {
> @@ -210,9 +208,6 @@ static unsigned long __init free_all_boo
>   				if (vec & 1) {
>   					page = pfn_to_page(start + off);
>   					__free_pages_bootmem(page, 0);
> -					fixup_zone_present_pages(
> -						page_to_nid(page),
> -						start + off, start + off + 1);
>   					count++;
>   				}
>   				vec >>= 1;
> @@ -226,11 +221,8 @@ static unsigned long __init free_all_boo
>   	pages = bdata->node_low_pfn - bdata->node_min_pfn;
>   	pages = bootmem_bootmap_pages(pages);
>   	count += pages;
> -	while (pages--) {
> -		fixup_zone_present_pages(page_to_nid(page),
> -				page_to_pfn(page), page_to_pfn(page) + 1);
> +	while (pages--)
>   		__free_pages_bootmem(page++, 0);
> -	}
>
>   	bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
>
> diff -puN mm/memory_hotplug.c~revert-1 mm/memory_hotplug.c
> --- a/mm/memory_hotplug.c~revert-1
> +++ a/mm/memory_hotplug.c
> @@ -106,7 +106,6 @@ static void get_page_bootmem(unsigned lo
>   void __ref put_page_bootmem(struct page *page)
>   {
>   	unsigned long type;
> -	struct zone *zone;
>
>   	type = (unsigned long) page->lru.next;
>   	BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
> @@ -117,12 +116,6 @@ void __ref put_page_bootmem(struct page
>   		set_page_private(page, 0);
>   		INIT_LIST_HEAD(&page->lru);
>   		__free_pages_bootmem(page, 0);
> -
> -		zone = page_zone(page);
> -		zone_span_writelock(zone);
> -		zone->present_pages++;
> -		zone_span_writeunlock(zone);
> -		totalram_pages++;
>   	}
>
>   }
> diff -puN mm/nobootmem.c~revert-1 mm/nobootmem.c
> --- a/mm/nobootmem.c~revert-1
> +++ a/mm/nobootmem.c
> @@ -116,8 +116,6 @@ static unsigned long __init __free_memor
>   		return 0;
>
>   	__free_pages_memory(start_pfn, end_pfn);
> -	fixup_zone_present_pages(pfn_to_nid(start >> PAGE_SHIFT),
> -			start_pfn, end_pfn);
>
>   	return end_pfn - start_pfn;
>   }
> @@ -128,7 +126,6 @@ unsigned long __init free_low_memory_cor
>   	phys_addr_t start, end, size;
>   	u64 i;
>
> -	reset_zone_present_pages();
>   	for_each_free_mem_range(i, MAX_NUMNODES, &start, &end, NULL)
>   		count += __free_memory_core(start, end);
>
> diff -puN mm/page_alloc.c~revert-1 mm/page_alloc.c
> --- a/mm/page_alloc.c~revert-1
> +++ a/mm/page_alloc.c
> @@ -6098,37 +6098,3 @@ void dump_page(struct page *page)
>   	dump_page_flags(page->flags);
>   	mem_cgroup_print_bad_page(page);
>   }
> -
> -/* reset zone->present_pages */
> -void reset_zone_present_pages(void)
> -{
> -	struct zone *z;
> -	int i, nid;
> -
> -	for_each_node_state(nid, N_HIGH_MEMORY) {
> -		for (i = 0; i < MAX_NR_ZONES; i++) {
> -			z = NODE_DATA(nid)->node_zones + i;
> -			z->present_pages = 0;
> -		}
> -	}
> -}
> -
> -/* calculate zone's present pages in buddy system */
> -void fixup_zone_present_pages(int nid, unsigned long start_pfn,
> -				unsigned long end_pfn)
> -{
> -	struct zone *z;
> -	unsigned long zone_start_pfn, zone_end_pfn;
> -	int i;
> -
> -	for (i = 0; i < MAX_NR_ZONES; i++) {
> -		z = NODE_DATA(nid)->node_zones + i;
> -		zone_start_pfn = z->zone_start_pfn;
> -		zone_end_pfn = zone_start_pfn + z->spanned_pages;
> -
> -		/* if the two regions intersect */
> -		if (!(zone_start_pfn >= end_pfn	|| zone_end_pfn <= start_pfn))
> -			z->present_pages += min(end_pfn, zone_end_pfn) -
> -					    max(start_pfn, zone_start_pfn);
> -	}
> -}
> _
>

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