diff mbox series

[v2,3/3] mm: return zero_resv_unavail optimization

Message ID 20180925153532.6206-4-msys.mizuma@gmail.com (mailing list archive)
State New, archived
Headers show
Series mm: Fix for movable_node boot option | expand

Commit Message

Masayoshi Mizuma Sept. 25, 2018, 3:35 p.m. UTC
From: Pavel Tatashin <pavel.tatashin@microsoft.com>

When checking for valid pfns in zero_resv_unavail(), it is not necessary to
verify that pfns within pageblock_nr_pages ranges are valid, only the first
one needs to be checked. This is because memory for pages are allocated in
contiguous chunks that contain pageblock_nr_pages struct pages.

Signed-off-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reviewed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
---
 mm/page_alloc.c | 46 ++++++++++++++++++++++++++--------------------
 1 file changed, 26 insertions(+), 20 deletions(-)

Comments

Naoya Horiguchi Sept. 28, 2018, 12:19 a.m. UTC | #1
On Tue, Sep 25, 2018 at 11:35:32AM -0400, Masayoshi Mizuma wrote:
> From: Pavel Tatashin <pavel.tatashin@microsoft.com>
> 
> When checking for valid pfns in zero_resv_unavail(), it is not necessary to
> verify that pfns within pageblock_nr_pages ranges are valid, only the first
> one needs to be checked. This is because memory for pages are allocated in
> contiguous chunks that contain pageblock_nr_pages struct pages.
> 
> Signed-off-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
> Reviewed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>

According to convention, review tag is formatted like "Reviewed-by: ...",
Otherwise, looks good to me.

Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

> ---
>  mm/page_alloc.c | 46 ++++++++++++++++++++++++++--------------------
>  1 file changed, 26 insertions(+), 20 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 3b9d89e..bd5b7e4 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -6440,6 +6440,29 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
>  }
>  
>  #if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP)
> +
> +/*
> + * Zero all valid struct pages in range [spfn, epfn), return number of struct
> + * pages zeroed
> + */
> +static u64 zero_pfn_range(unsigned long spfn, unsigned long epfn)
> +{
> +	unsigned long pfn;
> +	u64 pgcnt = 0;
> +
> +	for (pfn = spfn; pfn < epfn; pfn++) {
> +		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
> +			pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
> +				+ pageblock_nr_pages - 1;
> +			continue;
> +		}
> +		mm_zero_struct_page(pfn_to_page(pfn));
> +		pgcnt++;
> +	}
> +
> +	return pgcnt;
> +}
> +
>  /*
>   * Only struct pages that are backed by physical memory are zeroed and
>   * initialized by going through __init_single_page(). But, there are some
> @@ -6455,7 +6478,6 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
>  void __init zero_resv_unavail(void)
>  {
>  	phys_addr_t start, end;
> -	unsigned long pfn;
>  	u64 i, pgcnt;
>  	phys_addr_t next = 0;
>  
> @@ -6465,34 +6487,18 @@ void __init zero_resv_unavail(void)
>  	pgcnt = 0;
>  	for_each_mem_range(i, &memblock.memory, NULL,
>  			NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) {
> -		if (next < start) {
> -			for (pfn = PFN_DOWN(next); pfn < PFN_UP(start); pfn++) {
> -				if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages)))
> -					continue;
> -				mm_zero_struct_page(pfn_to_page(pfn));
> -				pgcnt++;
> -			}
> -		}
> +		if (next < start)
> +			pgcnt += zero_pfn_range(PFN_DOWN(next), PFN_UP(start));
>  		next = end;
>  	}
> -	for (pfn = PFN_DOWN(next); pfn < max_pfn; pfn++) {
> -		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages)))
> -			continue;
> -		mm_zero_struct_page(pfn_to_page(pfn));
> -		pgcnt++;
> -	}
> -
> +	pgcnt += zero_pfn_range(PFN_DOWN(next), max_pfn);
>  
>  	/*
>  	 * Struct pages that do not have backing memory. This could be because
>  	 * firmware is using some of this memory, or for some other reasons.
> -	 * Once memblock is changed so such behaviour is not allowed: i.e.
> -	 * list of "reserved" memory must be a subset of list of "memory", then
> -	 * this code can be removed.
>  	 */
>  	if (pgcnt)
>  		pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
> -
>  }
>  #endif /* CONFIG_HAVE_MEMBLOCK && !CONFIG_FLAT_NODE_MEM_MAP */
>  
> -- 
> 2.18.0
> 
>
Masayoshi Mizuma Sept. 28, 2018, 3:36 p.m. UTC | #2
On Fri, Sep 28, 2018 at 12:19:44AM +0000, Naoya Horiguchi wrote:
> On Tue, Sep 25, 2018 at 11:35:32AM -0400, Masayoshi Mizuma wrote:
> > From: Pavel Tatashin <pavel.tatashin@microsoft.com>
> > 
> > When checking for valid pfns in zero_resv_unavail(), it is not necessary to
> > verify that pfns within pageblock_nr_pages ranges are valid, only the first
> > one needs to be checked. This is because memory for pages are allocated in
> > contiguous chunks that contain pageblock_nr_pages struct pages.
> > 
> > Signed-off-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
> > Reviewed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
> 
> According to convention, review tag is formatted like "Reviewed-by: ...",

Sorry for the typo...

> Otherwise, looks good to me.
> 
> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

Thanks!

- Masa

> 
> > ---
> >  mm/page_alloc.c | 46 ++++++++++++++++++++++++++--------------------
> >  1 file changed, 26 insertions(+), 20 deletions(-)
> > 
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index 3b9d89e..bd5b7e4 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -6440,6 +6440,29 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
> >  }
> >  
> >  #if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP)
> > +
> > +/*
> > + * Zero all valid struct pages in range [spfn, epfn), return number of struct
> > + * pages zeroed
> > + */
> > +static u64 zero_pfn_range(unsigned long spfn, unsigned long epfn)
> > +{
> > +	unsigned long pfn;
> > +	u64 pgcnt = 0;
> > +
> > +	for (pfn = spfn; pfn < epfn; pfn++) {
> > +		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
> > +			pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
> > +				+ pageblock_nr_pages - 1;
> > +			continue;
> > +		}
> > +		mm_zero_struct_page(pfn_to_page(pfn));
> > +		pgcnt++;
> > +	}
> > +
> > +	return pgcnt;
> > +}
> > +
> >  /*
> >   * Only struct pages that are backed by physical memory are zeroed and
> >   * initialized by going through __init_single_page(). But, there are some
> > @@ -6455,7 +6478,6 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
> >  void __init zero_resv_unavail(void)
> >  {
> >  	phys_addr_t start, end;
> > -	unsigned long pfn;
> >  	u64 i, pgcnt;
> >  	phys_addr_t next = 0;
> >  
> > @@ -6465,34 +6487,18 @@ void __init zero_resv_unavail(void)
> >  	pgcnt = 0;
> >  	for_each_mem_range(i, &memblock.memory, NULL,
> >  			NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) {
> > -		if (next < start) {
> > -			for (pfn = PFN_DOWN(next); pfn < PFN_UP(start); pfn++) {
> > -				if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages)))
> > -					continue;
> > -				mm_zero_struct_page(pfn_to_page(pfn));
> > -				pgcnt++;
> > -			}
> > -		}
> > +		if (next < start)
> > +			pgcnt += zero_pfn_range(PFN_DOWN(next), PFN_UP(start));
> >  		next = end;
> >  	}
> > -	for (pfn = PFN_DOWN(next); pfn < max_pfn; pfn++) {
> > -		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages)))
> > -			continue;
> > -		mm_zero_struct_page(pfn_to_page(pfn));
> > -		pgcnt++;
> > -	}
> > -
> > +	pgcnt += zero_pfn_range(PFN_DOWN(next), max_pfn);
> >  
> >  	/*
> >  	 * Struct pages that do not have backing memory. This could be because
> >  	 * firmware is using some of this memory, or for some other reasons.
> > -	 * Once memblock is changed so such behaviour is not allowed: i.e.
> > -	 * list of "reserved" memory must be a subset of list of "memory", then
> > -	 * this code can be removed.
> >  	 */
> >  	if (pgcnt)
> >  		pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
> > -
> >  }
> >  #endif /* CONFIG_HAVE_MEMBLOCK && !CONFIG_FLAT_NODE_MEM_MAP */
> >  
> > -- 
> > 2.18.0
> > 
> >
diff mbox series

Patch

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3b9d89e..bd5b7e4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6440,6 +6440,29 @@  void __init free_area_init_node(int nid, unsigned long *zones_size,
 }
 
 #if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP)
+
+/*
+ * Zero all valid struct pages in range [spfn, epfn), return number of struct
+ * pages zeroed
+ */
+static u64 zero_pfn_range(unsigned long spfn, unsigned long epfn)
+{
+	unsigned long pfn;
+	u64 pgcnt = 0;
+
+	for (pfn = spfn; pfn < epfn; pfn++) {
+		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
+			pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
+				+ pageblock_nr_pages - 1;
+			continue;
+		}
+		mm_zero_struct_page(pfn_to_page(pfn));
+		pgcnt++;
+	}
+
+	return pgcnt;
+}
+
 /*
  * Only struct pages that are backed by physical memory are zeroed and
  * initialized by going through __init_single_page(). But, there are some
@@ -6455,7 +6478,6 @@  void __init free_area_init_node(int nid, unsigned long *zones_size,
 void __init zero_resv_unavail(void)
 {
 	phys_addr_t start, end;
-	unsigned long pfn;
 	u64 i, pgcnt;
 	phys_addr_t next = 0;
 
@@ -6465,34 +6487,18 @@  void __init zero_resv_unavail(void)
 	pgcnt = 0;
 	for_each_mem_range(i, &memblock.memory, NULL,
 			NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) {
-		if (next < start) {
-			for (pfn = PFN_DOWN(next); pfn < PFN_UP(start); pfn++) {
-				if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages)))
-					continue;
-				mm_zero_struct_page(pfn_to_page(pfn));
-				pgcnt++;
-			}
-		}
+		if (next < start)
+			pgcnt += zero_pfn_range(PFN_DOWN(next), PFN_UP(start));
 		next = end;
 	}
-	for (pfn = PFN_DOWN(next); pfn < max_pfn; pfn++) {
-		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages)))
-			continue;
-		mm_zero_struct_page(pfn_to_page(pfn));
-		pgcnt++;
-	}
-
+	pgcnt += zero_pfn_range(PFN_DOWN(next), max_pfn);
 
 	/*
 	 * Struct pages that do not have backing memory. This could be because
 	 * firmware is using some of this memory, or for some other reasons.
-	 * Once memblock is changed so such behaviour is not allowed: i.e.
-	 * list of "reserved" memory must be a subset of list of "memory", then
-	 * this code can be removed.
 	 */
 	if (pgcnt)
 		pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
-
 }
 #endif /* CONFIG_HAVE_MEMBLOCK && !CONFIG_FLAT_NODE_MEM_MAP */