+ mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid.patch added to -mm tree

* + mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid.patch added to -mm tree
@ 2015-04-29 21:19 akpm
  0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2015-04-29 21:19 UTC (permalink / raw)
  To: mgorman, daniel, dave.hansen, hpa, mingo, nzimmer, penberg,
	robinmholt, scott.norton, tglx, tony.luck, waiman.long,
	mm-commits


The patch titled
     Subject: mm: meminit: make __early_pfn_to_nid SMP-safe and introduce meminit_pfn_in_nid
has been added to the -mm tree.  Its filename is
     mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid.patch

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*** Remember to use Documentation/SubmitChecklist when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Mel Gorman <mgorman@suse.de>
Subject: mm: meminit: make __early_pfn_to_nid SMP-safe and introduce meminit_pfn_in_nid

__early_pfn_to_nid() use static variables to cache recent lookups as
memblock lookups are very expensive but it assumes that memory
initialisation is single-threaded.  Parallel initialisation of struct
pages will break that assumption so this patch makes __early_pfn_to_nid()
SMP-safe by requiring the caller to cache recent search information. 
early_pfn_to_nid() keeps the same interface but is only safe to use early
in boot due to the use of a global static variable.  meminit_pfn_in_nid()
is an SMP-safe version that callers must maintain their own state for.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Nate Zimmer <nzimmer@sgi.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: Daniel J Blueman <daniel@numascale.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/ia64/mm/numa.c    |   19 ++++++------------
 include/linux/mm.h     |    6 +++--
 include/linux/mmzone.h |   16 ++++++++++++++-
 mm/page_alloc.c        |   40 ++++++++++++++++++++++++---------------
 4 files changed, 51 insertions(+), 30 deletions(-)

diff -puN arch/ia64/mm/numa.c~mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid arch/ia64/mm/numa.c

--- a/arch/ia64/mm/numa.c~mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid
+++ a/arch/ia64/mm/numa.c
@@ -58,27 +58,22 @@ paddr_to_nid(unsigned long paddr)
  * SPARSEMEM to allocate the SPARSEMEM sectionmap on the NUMA node where
  * the section resides.
  */
-int __meminit __early_pfn_to_nid(unsigned long pfn)
+int __meminit __early_pfn_to_nid(unsigned long pfn,
+					struct mminit_pfnnid_cache *state)
 {
 	int i, section = pfn >> PFN_SECTION_SHIFT, ssec, esec;
-	/*
-	 * NOTE: The following SMP-unsafe globals are only used early in boot
-	 * when the kernel is running single-threaded.
-	 */
-	static int __meminitdata last_ssec, last_esec;
-	static int __meminitdata last_nid;
 
-	if (section >= last_ssec && section < last_esec)
-		return last_nid;
+	if (section >= state->last_start && section < state->last_end)
+		return state->last_nid;
 
 	for (i = 0; i < num_node_memblks; i++) {
 		ssec = node_memblk[i].start_paddr >> PA_SECTION_SHIFT;
 		esec = (node_memblk[i].start_paddr + node_memblk[i].size +
 			((1L << PA_SECTION_SHIFT) - 1)) >> PA_SECTION_SHIFT;
 		if (section >= ssec && section < esec) {
-			last_ssec = ssec;
-			last_esec = esec;
-			last_nid = node_memblk[i].nid;
+			state->last_start = ssec;
+			state->last_end = esec;
+			state->last_nid = node_memblk[i].nid;
 			return node_memblk[i].nid;
 		}
 	}
diff -puN include/linux/mm.h~mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid include/linux/mm.h
--- a/include/linux/mm.h~mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid
+++ a/include/linux/mm.h
@@ -1722,7 +1722,8 @@ extern void sparse_memory_present_with_a
 
 #if !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && \
     !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)
-static inline int __early_pfn_to_nid(unsigned long pfn)
+static inline int __early_pfn_to_nid(unsigned long pfn,
+					struct mminit_pfnnid_cache *state)
 {
 	return 0;
 }
@@ -1730,7 +1731,8 @@ static inline int __early_pfn_to_nid(uns
 /* please see mm/page_alloc.c */
 extern int __meminit early_pfn_to_nid(unsigned long pfn);
 /* there is a per-arch backend function. */
-extern int __meminit __early_pfn_to_nid(unsigned long pfn);
+extern int __meminit __early_pfn_to_nid(unsigned long pfn,
+					struct mminit_pfnnid_cache *state);
 #endif
 
 extern void set_dma_reserve(unsigned long new_dma_reserve);
diff -puN include/linux/mmzone.h~mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid include/linux/mmzone.h
--- a/include/linux/mmzone.h~mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid
+++ a/include/linux/mmzone.h
@@ -1216,10 +1216,24 @@ void sparse_init(void);
 #define sparse_index_init(_sec, _nid)  do {} while (0)
 #endif /* CONFIG_SPARSEMEM */
 
+/*
+ * During memory init memblocks map pfns to nids. The search is expensive and
+ * this caches recent lookups. The implementation of __early_pfn_to_nid
+ * may treat start/end as pfns or sections.
+ */
+struct mminit_pfnnid_cache {
+	unsigned long last_start;
+	unsigned long last_end;
+	int last_nid;
+};
+
 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
 bool early_pfn_in_nid(unsigned long pfn, int nid);
+bool meminit_pfn_in_nid(unsigned long pfn, int node,
+			struct mminit_pfnnid_cache *state);
 #else
-#define early_pfn_in_nid(pfn, nid)	(1)
+#define early_pfn_in_nid(pfn, nid)		(1)
+#define meminit_pfn_in_nid(pfn, nid, state)	(1)
 #endif
 
 #ifndef early_pfn_valid
diff -puN mm/page_alloc.c~mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid mm/page_alloc.c
--- a/mm/page_alloc.c~mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid
+++ a/mm/page_alloc.c
@@ -4506,39 +4506,41 @@ int __meminit init_currently_empty_zone(
 
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
+
 /*
  * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
  */
-int __meminit __early_pfn_to_nid(unsigned long pfn)
+int __meminit __early_pfn_to_nid(unsigned long pfn,
+					struct mminit_pfnnid_cache *state)
 {
 	unsigned long start_pfn, end_pfn;
 	int nid;
-	/*
-	 * NOTE: The following SMP-unsafe globals are only used early in boot
-	 * when the kernel is running single-threaded.
-	 */
-	static unsigned long __meminitdata last_start_pfn, last_end_pfn;
-	static int __meminitdata last_nid;
 
-	if (last_start_pfn <= pfn && pfn < last_end_pfn)
-		return last_nid;
+	if (state->last_start <= pfn && pfn < state->last_end)
+		return state->last_nid;
 
 	nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
 	if (nid != -1) {
-		last_start_pfn = start_pfn;
-		last_end_pfn = end_pfn;
-		last_nid = nid;
+		state->last_start = start_pfn;
+		state->last_end = end_pfn;
+		state->last_nid = nid;
 	}
 
 	return nid;
 }
 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
 
+static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
+
+/* Only safe to use early in boot when initialisation is single-threaded */
 int __meminit early_pfn_to_nid(unsigned long pfn)
 {
 	int nid;
 
-	nid = __early_pfn_to_nid(pfn);
+	/* The system will behave unpredictably otherwise */
+	BUG_ON(system_state != SYSTEM_BOOTING);
+
+	nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
 	if (nid >= 0)
 		return nid;
 	/* just returns 0 */
@@ -4546,15 +4548,23 @@ int __meminit early_pfn_to_nid(unsigned
 }
 
 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
-bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
+bool __meminit meminit_pfn_in_nid(unsigned long pfn, int node,
+					struct mminit_pfnnid_cache *state)
 {
 	int nid;
 
-	nid = __early_pfn_to_nid(pfn);
+	nid = __early_pfn_to_nid(pfn, state);
 	if (nid >= 0 && nid != node)
 		return false;
 	return true;
 }
+
+/* Only safe to use early in boot when initialisation is single-threaded */
+bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
+{
+	return meminit_pfn_in_nid(pfn, node, &early_pfnnid_cache);
+}
+
 #endif
 
 /**
_

Patches currently in -mm which might be from mgorman@suse.de are

jbd2-revert-must-not-fail-allocation-loops-back-to-gfp_nofail.patch
thp-cleanup-how-khugepaged-enters-freezer.patch
mm-new-mm-hook-framework.patch
mm-new-arch_remap-hook.patch
powerpc-mm-tracking-vdso-remap.patch
memblock-introduce-a-for_each_reserved_mem_region-iterator.patch
mm-meminit-move-page-initialization-into-a-separate-function.patch
mm-meminit-only-set-page-reserved-in-the-memblock-region.patch
mm-page_alloc-pass-pfn-to-__free_pages_bootmem.patch
mm-meminit-make-__early_pfn_to_nid-smp-safe-and-introduce-meminit_pfn_in_nid.patch
mm-meminit-inline-some-helper-functions.patch
mm-meminit-initialise-a-subset-of-struct-pages-if-config_deferred_struct_page_init-is-set.patch
mm-meminit-initialise-remaining-struct-pages-in-parallel-with-kswapd.patch
mm-meminit-minimise-number-of-pfn-page-lookups-during-initialisation.patch
x86-mm-enable-deferred-struct-page-initialisation-on-x86-64.patch
mm-meminit-free-pages-in-large-chunks-where-possible.patch
mm-meminit-reduce-number-of-times-pageblocks-are-set-during-struct-page-init.patch
mm-meminit-remove-mminit_verify_page_links.patch
page-flags-trivial-cleanup-for-pagetrans-helpers.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages.patch
page-flags-define-pg_locked-behavior-on-compound-pages.patch
page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch
page-flags-define-behavior-slb-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages.patch
page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch
page-flags-define-pg_swapcache-behavior-on-compound-pages.patch
page-flags-define-pg_mlocked-behavior-on-compound-pages.patch
page-flags-define-pg_uncached-behavior-on-compound-pages.patch
page-flags-define-pg_uptodate-behavior-on-compound-pages.patch
page-flags-look-on-head-page-if-the-flag-is-encoded-in-page-mapping.patch
mm-sanitize-page-mapping-for-tail-pages.patch
mm-vmscan-do-not-throttle-based-on-pfmemalloc-reserves-if-node-has-no-reclaimable-pages.patch
mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated.patch
mm-move-lazy-free-pages-to-inactive-list.patch
mm-move-lazy-free-pages-to-inactive-list-fix.patch
mm-move-lazy-free-pages-to-inactive-list-fix-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch


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