linux-kernel - [PATCH] [27/36] CPA: Only queue actually unused page table pages for freeing

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Message-Id: <20080116221527.1907F150C8@wotan.suse.de>
Date:	Wed, 16 Jan 2008 23:15:27 +0100 (CET)
From:	Andi Kleen <ak@...e.de>
To:	linux-kernel@...r.kernel.org, mingo@...e.hu, tglx@...utronix.de,
	jbeulich@...ell.com, venkatesh.pallipadi@...el.com
Subject: [PATCH] [27/36] CPA: Only queue actually unused page table pages for freeing


With the separate data structure added for flush earlier it is only
needed to call save_page() now on pte pages that have been already reverted.

Also move all freeing checks into the caller.

Signed-off-by: Andi Kleen <ak@...e.de>
Acked-by: Jan Beulich <jbeulich@...ell.com>

---
 arch/x86/mm/pageattr_32.c |    4 +---
 arch/x86/mm/pageattr_64.c |    7 +++----
 2 files changed, 4 insertions(+), 7 deletions(-)

Index: linux/arch/x86/mm/pageattr_32.c
===================================================================
--- linux.orig/arch/x86/mm/pageattr_32.c
+++ linux/arch/x86/mm/pageattr_32.c
@@ -270,9 +270,9 @@ __change_page_attr(struct page *page, pg
 	 * replace it with a largepage.
 	 */
 
-	save_page(kpte_page);
 	if (!PageReserved(kpte_page)) {
 		if (cpu_has_pse && (page_private(kpte_page) == 0)) {
+			save_page(kpte_page);
 			paravirt_release_pt(page_to_pfn(kpte_page));
 			revert_page(kpte_page, address);
 		}
@@ -349,8 +349,6 @@ void global_flush_tlb(void)
 	list_for_each_entry_safe(pg, next, &free_pages, lru) {
 		list_del(&pg->lru);
 		ClearPageDeferred(pg);
-		if (PageReserved(pg) || !cpu_has_pse || page_private(pg) != 0)
-			continue;
 		ClearPagePrivate(pg);
 		__free_page(pg);
 	}
Index: linux/arch/x86/mm/pageattr_64.c
===================================================================
--- linux.orig/arch/x86/mm/pageattr_64.c
+++ linux/arch/x86/mm/pageattr_64.c
@@ -243,9 +243,10 @@ __change_page_attr(unsigned long address
 		BUG();
 	}
 
-	save_page(kpte_page);
-	if (!PageReserved(kpte_page) && page_private(kpte_page) == 0)
+	if (!PageReserved(kpte_page) && page_private(kpte_page) == 0) {
+		save_page(kpte_page);
 		revert_page(address, ref_prot);
+	}
 	return 0;
 } 
 
@@ -335,8 +336,6 @@ void global_flush_tlb(void)
 		if (PageReserved(pg))
 			continue;
 		ClearPageDeferred(pg);
-		if (page_private(pg) != 0)
-			continue;
 		ClearPagePrivate(pg);
 		__free_page(pg);
 	} 
--
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