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From: Qian Cai <cai@lca.pw>
To: Mike Rapoport <rppt@kernel.org>, Baoquan He <bhe@redhat.com>
Cc: Rich Felker <dalias@libc.org>,
	linux-ia64@vger.kernel.org, linux-doc@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Michal Hocko <mhocko@kernel.org>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Max Filippov <jcmvbkbc@gmail.com>, Guo Ren <guoren@kernel.org>,
	linux-csky@vger.kernel.org, linux-parisc@vger.kernel.org,
	sparclinux@vger.kernel.org, linux-hexagon@vger.kernel.org,
	linux-riscv@lists.infradead.org,
	Greg Ungerer <gerg@linux-m68k.org>,
	linux-arch@vger.kernel.org, linux-s390@vger.kernel.org,
	linux-snps-arc@lists.infradead.org, linux-c6x-dev@linux-c6x.org,
	Brian Cain <bcain@codeaurora.org>,
	Jonathan Corbet <corbet@lwn.net>,
	linux-sh@vger.kernel.org, Michael Ellerman <mpe@ellerman.id.au>,
	Helge Deller <deller@gmx.de>,
	the arch/x86 maintainers <x86@kernel.org>,
	Russell King <linux@armlinux.org.u>
Subject: Re: [PATCH 15/21] mm: memmap_init: iterate over memblock regions rather that check each PFN
Date: Mon, 20 Apr 2020 10:26:06 -0400
Message-ID: <CF6E407F-17DC-427C-8203-21979FB882EF@lca.pw> (raw)
In-Reply-To: <20200412194859.12663-16-rppt@kernel.org>



> On Apr 12, 2020, at 3:48 PM, Mike Rapoport <rppt@kernel.org> wrote:
> 
> From: Baoquan He <bhe@redhat.com>
> 
> When called during boot the memmap_init_zone() function checks if each PFN
> is valid and actually belongs to the node being initialized using
> early_pfn_valid() and early_pfn_in_nid().
> 
> Each such check may cost up to O(log(n)) where n is the number of memory
> banks, so for large amount of memory overall time spent in early_pfn*()
> becomes substantial.
> 
> Since the information is anyway present in memblock, we can iterate over
> memblock memory regions in memmap_init() and only call memmap_init_zone()
> for PFN ranges that are know to be valid and in the appropriate node.
> 
> Signed-off-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> mm/page_alloc.c | 26 ++++++++++++++++----------
> 1 file changed, 16 insertions(+), 10 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 7f6a3081edb8..c43ce8709457 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5995,14 +5995,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
> 		 * function.  They do not exist on hotplugged memory.
> 		 */
> 		if (context == MEMMAP_EARLY) {
> -			if (!early_pfn_valid(pfn)) {
> -				pfn = next_pfn(pfn);
> -				continue;
> -			}
> -			if (!early_pfn_in_nid(pfn, nid)) {
> -				pfn++;
> -				continue;
> -			}

This causes a compilation warning from Clang,

mm/page_alloc.c:5917:39: warning: unused function 'next_pfn' [-Wunused-function]
static inline __meminit unsigned long next_pfn(unsigned long pfn)

This should fix it,

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d469384c9ca7..b48336e20bdc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5912,23 +5912,6 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn)
 	return false;
 }
 
-#ifdef CONFIG_SPARSEMEM
-/* Skip PFNs that belong to non-present sections */
-static inline __meminit unsigned long next_pfn(unsigned long pfn)
-{
-	const unsigned long section_nr = pfn_to_section_nr(++pfn);
-
-	if (present_section_nr(section_nr))
-		return pfn;
-	return section_nr_to_pfn(next_present_section_nr(section_nr));
-}
-#else
-static inline __meminit unsigned long next_pfn(unsigned long pfn)
-{
-	return pfn++;
-}
-#endif
-
 /*
  * Initially all pages are reserved - free ones are freed
  * up by memblock_free_all() once the early boot process is

> 			if (overlap_memmap_init(zone, &pfn))
> 				continue;
> 			if (defer_init(nid, pfn, end_pfn))
> @@ -6118,9 +6110,23 @@ static void __meminit zone_init_free_lists(struct zone *zone)
> }
> 
> void __meminit __weak memmap_init(unsigned long size, int nid,
> -				  unsigned long zone, unsigned long start_pfn)
> +				  unsigned long zone,
> +				  unsigned long range_start_pfn)
> {
> -	memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL);
> +	unsigned long start_pfn, end_pfn;
> +	unsigned long range_end_pfn = range_start_pfn + size;
> +	int i;
> +
> +	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
> +		start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
> +		end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
> +
> +		if (end_pfn > start_pfn) {
> +			size = end_pfn - start_pfn;
> +			memmap_init_zone(size, nid, zone, start_pfn,
> +					 MEMMAP_EARLY, NULL);
> +		}
> +	}
> }
> 
> static int zone_batchsize(struct zone *zone)
> -- 
> 2.25.1
> 
> 

  reply index

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-12 19:48 [PATCH 00/21] mm: rework free_area_init*() funcitons Mike Rapoport
2020-04-12 19:48 ` [PATCH 01/21] mm: memblock: replace dereferences of memblock_region.nid with API calls Mike Rapoport
2020-04-21  2:06   ` Baoquan He
2020-04-12 19:48 ` [PATCH 02/21] mm: make early_pfn_to_nid() and related defintions close to each other Mike Rapoport
2020-04-21  2:24   ` Baoquan He
2020-04-21  8:49     ` Mike Rapoport
2020-04-21  8:49       ` Mike Rapoport
2020-04-21  9:33       ` Baoquan He
2020-04-21  3:31   ` Baoquan He
2020-04-21  8:39     ` Mike Rapoport
2020-04-21  8:39       ` Mike Rapoport
2020-04-12 19:48 ` [PATCH 03/21] mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option Mike Rapoport
2020-04-21  4:23   ` Baoquan He
2020-04-21  9:09     ` Mike Rapoport
2020-04-21  9:09       ` Mike Rapoport
2020-04-21  9:45       ` Baoquan He
2020-04-12 19:48 ` [PATCH 04/21] mm: free_area_init: use maximal zone PFNs rather than zone sizes Mike Rapoport
2020-04-22 23:41   ` Baoquan He
2020-06-15  3:53   ` Greg Ungerer
2020-06-15  6:22     ` Mike Rapoport
2020-06-15  6:22       ` Mike Rapoport
2020-06-15  7:17       ` Greg Ungerer
2020-04-12 19:48 ` [PATCH 05/21] mm: use free_area_init() instead of free_area_init_nodes() Mike Rapoport
2020-04-23  0:02   ` Baoquan He
2020-04-12 19:48 ` [PATCH 06/21] alpha: simplify detection of memory zone boundaries Mike Rapoport
2020-04-12 19:48 ` [PATCH 07/21] arm: " Mike Rapoport
2020-04-12 19:48 ` [PATCH 08/21] arm64: simplify detection of memory zone boundaries for UMA configs Mike Rapoport
2020-04-12 19:48 ` [PATCH 09/21] csky: simplify detection of memory zone boundaries Mike Rapoport
2020-04-12 19:48 ` [PATCH 10/21] m68k: mm: " Mike Rapoport
2020-04-12 19:48 ` [PATCH 11/21] parisc: " Mike Rapoport
2020-04-12 19:48 ` [PATCH 12/21] sparc32: " Mike Rapoport
2020-04-12 19:48 ` [PATCH 13/21] unicore32: " Mike Rapoport
2020-04-12 19:48 ` [PATCH 14/21] xtensa: " Mike Rapoport
2020-04-12 19:48 ` [PATCH 15/21] mm: memmap_init: iterate over memblock regions rather that check each PFN Mike Rapoport
2020-04-20 14:26   ` Qian Cai [this message]
2020-04-24  7:22   ` David Hildenbrand
2020-04-25 16:49     ` Mike Rapoport
2020-04-25 16:49       ` Mike Rapoport
2020-04-12 19:48 ` [PATCH 16/21] mm: remove early_pfn_in_nid() and CONFIG_NODES_SPAN_OTHER_NODES Mike Rapoport
2020-04-23  1:13   ` Baoquan He
2020-04-23  5:50     ` Mike Rapoport
2020-04-23  5:50       ` Mike Rapoport
2020-05-18 21:38     ` Hoan Tran
2020-04-12 19:48 ` [PATCH 17/21] mm: free_area_init: allow defining max_zone_pfn in descending order Mike Rapoport
2020-04-23  2:53   ` Baoquan He
2020-04-23  2:57     ` Baoquan He
2020-04-23  5:55       ` Mike Rapoport
2020-04-23  5:55         ` Mike Rapoport
2020-04-24  0:33         ` Baoquan He
2020-04-12 19:48 ` [PATCH 18/21] mm: rename free_area_init_node() to free_area_init_memoryless_node() Mike Rapoport
2020-04-23  3:14   ` Baoquan He
2020-04-23  6:18     ` Mike Rapoport
2020-04-23  6:18       ` Mike Rapoport
2020-04-12 19:48 ` [PATCH 19/21] mm: clean up free_area_init_node() and its helpers Mike Rapoport
2020-04-12 19:48 ` [PATCH 20/21] mm: simplify find_min_pfn_with_active_regions() Mike Rapoport
2020-04-12 19:48 ` [PATCH 21/21] docs/vm: update memory-models documentation Mike Rapoport

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