[PATCH 1/2] x86, mem-hotplug: separate x86_64 vmalloc_sync_all() into separate functions

[PATCH 1/2] x86, mem-hotplug: separate x86_64 vmalloc_sync_all() into separate functions

[Haicheng Li]

 From 04d9fc860db40f15ad629f8b341ff84b83a00a8d Mon Sep 17 00:00:00 2001
From: Haicheng Li <haicheng.li@linux.intel.com>
Date: Wed, 19 May 2010 17:42:14 +0800
Subject: [PATCH] x86, mem-hotplug: separate x86_64 vmalloc_sync_all() into separate functions

No behavior change here.

Move some of vmalloc_sync_all() code into a new function
sync_global_pgds() that will be useful for memory hotplug.

CC: Wu Fengguang <fengguang.wu@intel.com>
CC: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
---
  arch/x86/include/asm/pgtable_64.h |    2 ++
  arch/x86/mm/fault.c               |   24 +-----------------------
  arch/x86/mm/init_64.c             |   30 ++++++++++++++++++++++++++++++
  3 files changed, 33 insertions(+), 23 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
index 181be52..317026d 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -102,6 +102,8 @@ static inline void native_pgd_clear(pgd_t *pgd)
  	native_set_pgd(pgd, native_make_pgd(0));
  }

+extern void sync_global_pgds(unsigned long start, unsigned long end);
+
  /*
   * Conversion functions: convert a page and protection to a page entry,
   * and a page entry and page directory to the page they refer to.
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index f627779..7ae0897 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -326,29 +326,7 @@ out:

  void vmalloc_sync_all(void)
  {
-	unsigned long address;
-
-	for (address = VMALLOC_START & PGDIR_MASK; address <= VMALLOC_END;
-	     address += PGDIR_SIZE) {
-
-		const pgd_t *pgd_ref = pgd_offset_k(address);
-		unsigned long flags;
-		struct page *page;
-
-		if (pgd_none(*pgd_ref))
-			continue;
-
-		spin_lock_irqsave(&pgd_lock, flags);
-		list_for_each_entry(page, &pgd_list, lru) {
-			pgd_t *pgd;
-			pgd = (pgd_t *)page_address(page) + pgd_index(address);
-			if (pgd_none(*pgd))
-				set_pgd(pgd, *pgd_ref);
-			else
-				BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
-		}
-		spin_unlock_irqrestore(&pgd_lock, flags);
-	}
+	sync_global_pgds(VMALLOC_START & PGDIR_MASK, VMALLOC_END);
  }

  /*
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index ee41bba..b0c3df0 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -98,6 +98,36 @@ static int __init nonx32_setup(char *str)
  __setup("noexec32=", nonx32_setup);

  /*
+ * When memory was added/removed make sure all the processes MM have
+ * suitable PGD entries in the local PGD level page.
+ */
+void sync_global_pgds(unsigned long start, unsigned long end)
+{
+	unsigned long address;
+
+	for (address = start; address <= end; address += PGDIR_SIZE) {
+		const pgd_t *pgd_ref = pgd_offset_k(address);
+		unsigned long flags;
+		struct page *page;
+
+		if (pgd_none(*pgd_ref))
+			continue;
+
+		spin_lock_irqsave(&pgd_lock, flags);
+		list_for_each_entry(page, &pgd_list, lru) {
+			pgd_t *pgd;
+			pgd = (pgd_t *)page_address(page) + pgd_index(address);
+			if (pgd_none(*pgd))
+				set_pgd(pgd, *pgd_ref);
+			else
+				BUG_ON(pgd_page_vaddr(*pgd)
+					 != pgd_page_vaddr(*pgd_ref));
+		}
+		spin_unlock_irqrestore(&pgd_lock, flags);
+	}
+}
+
+/*
   * NOTE: This function is marked __ref because it calls __init function
   * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
   */
-- 
1.5.6.1

Re: [PATCH 1/2] x86, mem-hotplug: separate x86_64 vmalloc_sync_all() into separate functions

[Wu Fengguang]

> No behavior change here.
> 
> Move some of vmalloc_sync_all() code into a new function
> sync_global_pgds() that will be useful for memory hotplug.

This is a neat change, thank you!

Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>