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From: Joonsoo Kim <js1304@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Joonsoo Kim <js1304@gmail.com>
Subject: [PATCH 4/5] mm, highmem: makes flush_all_zero_pkmaps() return index of last flushed entry
Date: Mon, 29 Oct 2012 04:12:55 +0900	[thread overview]
Message-ID: <1351451576-2611-5-git-send-email-js1304@gmail.com> (raw)
In-Reply-To: <1351451576-2611-1-git-send-email-js1304@gmail.com>

In current code, after flush_all_zero_pkmaps() is invoked,
then re-iterate all pkmaps. It can be optimized if flush_all_zero_pkmaps()
return index of flushed entry. With this index,
we can immediately map highmem page to virtual address represented by index.
So change return type of flush_all_zero_pkmaps()
and return index of last flushed entry.

Signed-off-by: Joonsoo Kim <js1304@gmail.com>

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index ef788b5..0683869 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -32,6 +32,7 @@ static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
 
 #ifdef CONFIG_HIGHMEM
 #include <asm/highmem.h>
+#define PKMAP_INDEX_INVAL (-1)
 
 /* declarations for linux/mm/highmem.c */
 unsigned int nr_free_highpages(void);
diff --git a/mm/highmem.c b/mm/highmem.c
index 731cf9a..65beb9a 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -106,10 +106,10 @@ struct page *kmap_to_page(void *vaddr)
 	return virt_to_page(addr);
 }
 
-static void flush_all_zero_pkmaps(void)
+static int flush_all_zero_pkmaps(void)
 {
 	int i;
-	int need_flush = 0;
+	int index = PKMAP_INDEX_INVAL;
 
 	flush_cache_kmaps();
 
@@ -141,10 +141,12 @@ static void flush_all_zero_pkmaps(void)
 			  &pkmap_page_table[i]);
 
 		set_page_address(page, NULL);
-		need_flush = 1;
+		index = i;
 	}
-	if (need_flush)
+	if (index != PKMAP_INDEX_INVAL)
 		flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
+
+	return index;
 }
 
 /**
@@ -160,6 +162,7 @@ void kmap_flush_unused(void)
 static inline unsigned long map_new_virtual(struct page *page)
 {
 	unsigned long vaddr;
+	int index = PKMAP_INDEX_INVAL;
 	int count;
 
 start:
@@ -168,40 +171,45 @@ start:
 	for (;;) {
 		last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK;
 		if (!last_pkmap_nr) {
-			flush_all_zero_pkmaps();
-			count = LAST_PKMAP;
+			index = flush_all_zero_pkmaps();
+			if (index != PKMAP_INDEX_INVAL)
+				break; /* Found a usable entry */
 		}
-		if (!pkmap_count[last_pkmap_nr])
+		if (!pkmap_count[last_pkmap_nr]) {
+			index = last_pkmap_nr;
 			break;	/* Found a usable entry */
-		if (--count)
-			continue;
-
-		/*
-		 * Sleep for somebody else to unmap their entries
-		 */
-		{
-			DECLARE_WAITQUEUE(wait, current);
-
-			__set_current_state(TASK_UNINTERRUPTIBLE);
-			add_wait_queue(&pkmap_map_wait, &wait);
-			unlock_kmap();
-			schedule();
-			remove_wait_queue(&pkmap_map_wait, &wait);
-			lock_kmap();
-
-			/* Somebody else might have mapped it while we slept */
-			if (page_address(page))
-				return (unsigned long)page_address(page);
-
-			/* Re-start */
-			goto start;
 		}
+		if (--count == 0)
+			break;
 	}
-	vaddr = PKMAP_ADDR(last_pkmap_nr);
+
+	/*
+	 * Sleep for somebody else to unmap their entries
+	 */
+	if (index == PKMAP_INDEX_INVAL) {
+		DECLARE_WAITQUEUE(wait, current);
+
+		__set_current_state(TASK_UNINTERRUPTIBLE);
+		add_wait_queue(&pkmap_map_wait, &wait);
+		unlock_kmap();
+		schedule();
+		remove_wait_queue(&pkmap_map_wait, &wait);
+		lock_kmap();
+
+		/* Somebody else might have mapped it while we slept */
+		vaddr = (unsigned long)page_address(page);
+		if (vaddr)
+			return vaddr;
+
+		/* Re-start */
+		goto start;
+	}
+
+	vaddr = PKMAP_ADDR(index);
 	set_pte_at(&init_mm, vaddr,
-		   &(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));
+		   &(pkmap_page_table[index]), mk_pte(page, kmap_prot));
 
-	pkmap_count[last_pkmap_nr] = 1;
+	pkmap_count[index] = 1;
 	set_page_address(page, (void *)vaddr);
 
 	return vaddr;
-- 
1.7.9.5

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  parent reply	other threads:[~2012-10-28 19:15 UTC|newest]

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Yes>
2012-07-16 16:14 ` [PATCH 1/3] mm: correct return value of migrate_pages() Joonsoo Kim
2012-07-16 16:14   ` [PATCH 2/3] mm: fix possible incorrect return value of migrate_pages() syscall Joonsoo Kim
2012-07-16 17:26     ` Christoph Lameter
2012-07-16 17:40     ` Michal Nazarewicz
2012-07-16 17:59       ` JoonSoo Kim
2012-07-17 13:02         ` Michal Nazarewicz
2012-07-16 16:14   ` [PATCH 3/3] mm: fix return value in __alloc_contig_migrate_range() Joonsoo Kim
2012-07-16 17:29     ` Christoph Lameter
2012-07-16 17:40     ` Michal Nazarewicz
2012-07-16 18:40       ` JoonSoo Kim
2012-07-17 13:16         ` Michal Nazarewicz
2012-07-16 17:14   ` [PATCH 4] mm: fix possible incorrect return value of move_pages() syscall Joonsoo Kim
2012-07-16 17:30     ` Christoph Lameter
2012-07-16 17:23   ` [PATCH 1/3] mm: correct return value of migrate_pages() Christoph Lameter
2012-07-16 17:32     ` JoonSoo Kim
2012-07-16 17:37       ` Christoph Lameter
2012-07-16 17:40   ` Michal Nazarewicz
2012-07-16 17:57     ` JoonSoo Kim
2012-07-16 18:05       ` Christoph Lameter
2012-07-17 12:33 ` [PATCH 1/4 v2] mm: correct return value of migrate_pages() and migrate_huge_pages() Joonsoo Kim
2012-07-17 12:33   ` [PATCH 2/4 v2] mm: fix possible incorrect return value of migrate_pages() syscall Joonsoo Kim
2012-07-17 14:28     ` Christoph Lameter
2012-07-17 15:41       ` JoonSoo Kim
2012-07-17 12:33   ` [PATCH 3/4 v2] mm: fix return value in __alloc_contig_migrate_range() Joonsoo Kim
2012-07-17 13:25     ` Michal Nazarewicz
2012-07-17 15:45       ` JoonSoo Kim
2012-07-17 15:49         ` [PATCH 3/4 v3] " Joonsoo Kim
2012-07-17 12:33   ` [PATCH 4/4 v2] mm: fix possible incorrect return value of move_pages() syscall Joonsoo Kim
2012-07-27 17:55 ` [RESEND PATCH 1/4 v3] mm: correct return value of migrate_pages() and migrate_huge_pages() Joonsoo Kim
2012-07-27 17:55   ` [RESEND PATCH 2/4 v3] mm: fix possible incorrect return value of migrate_pages() syscall Joonsoo Kim
2012-07-27 20:57     ` Christoph Lameter
2012-07-28  6:16       ` JoonSoo Kim
2012-07-30 19:30         ` Christoph Lameter
2012-07-27 17:55   ` [RESEND PATCH 3/4 v3] mm: fix return value in __alloc_contig_migrate_range() Joonsoo Kim
2012-07-27 17:55   ` [RESEND PATCH 4/4 v3] mm: fix possible incorrect return value of move_pages() syscall Joonsoo Kim
2012-07-27 20:54     ` Christoph Lameter
2012-07-28  6:09       ` JoonSoo Kim
2012-07-30 19:29         ` Christoph Lameter
2012-07-31  3:34           ` JoonSoo Kim
2012-07-31 14:04             ` Christoph Lameter
2012-08-01  5:15           ` Michael Kerrisk
2012-08-01 18:00             ` Christoph Lameter
2012-08-02  5:52               ` Michael Kerrisk
2012-08-24 16:05 ` [PATCH 1/2] slub: rename cpu_partial to max_cpu_object Joonsoo Kim
2012-08-24 16:05   ` [PATCH 2/2] slub: correct the calculation of the number of cpu objects in get_partial_node Joonsoo Kim
2012-08-24 16:15     ` Christoph Lameter
2012-08-24 16:28       ` JoonSoo Kim
2012-08-24 16:31         ` Christoph Lameter
2012-08-24 16:40           ` JoonSoo Kim
2012-08-24 16:12   ` [PATCH 1/2] slub: rename cpu_partial to max_cpu_object Christoph Lameter
2012-08-25 14:11 ` [PATCH 1/2] slab: do ClearSlabPfmemalloc() for all pages of slab Joonsoo Kim
2012-08-25 14:11   ` [PATCH 2/2] slab: fix starting index for finding another object Joonsoo Kim
2012-09-03 10:08   ` [PATCH 1/2] slab: do ClearSlabPfmemalloc() for all pages of slab Mel Gorman
2012-10-20 15:48 ` [PATCH for-v3.7 1/2] slub: optimize poorly inlined kmalloc* functions Joonsoo Kim
2012-10-20 15:48   ` [PATCH for-v3.7 2/2] slub: optimize kmalloc* inlining for GFP_DMA Joonsoo Kim
2012-10-22 14:31     ` Christoph Lameter
2012-10-23  2:29       ` JoonSoo Kim
2012-10-23  6:16         ` Eric Dumazet
2012-10-23 16:12           ` JoonSoo Kim
2012-10-24  8:05   ` [PATCH for-v3.7 1/2] slub: optimize poorly inlined kmalloc* functions Pekka Enberg
2012-10-24 13:36     ` Christoph Lameter
2012-10-28 19:12 ` [PATCH 0/5] minor clean-up and optimize highmem related code Joonsoo Kim
2012-10-28 19:12   ` [PATCH 1/5] mm, highmem: use PKMAP_NR() to calculate an index of pkmap Joonsoo Kim
2012-10-29  1:48     ` Minchan Kim
2012-10-28 19:12   ` [PATCH 2/5] mm, highmem: remove useless pool_lock Joonsoo Kim
2012-10-29  1:52     ` Minchan Kim
2012-10-30 21:31     ` Andrew Morton
2012-10-31  5:14       ` Minchan Kim
2012-10-31 15:01       ` JoonSoo Kim
2012-10-28 19:12   ` [PATCH 3/5] mm, highmem: remove page_address_pool list Joonsoo Kim
2012-10-29  1:57     ` Minchan Kim
2012-10-28 19:12   ` Joonsoo Kim [this message]
2012-10-29  2:06     ` [PATCH 4/5] mm, highmem: makes flush_all_zero_pkmaps() return index of last flushed entry Minchan Kim
2012-10-29 13:12       ` JoonSoo Kim
2012-10-28 19:12   ` [PATCH 5/5] mm, highmem: get virtual address of the page using PKMAP_ADDR() Joonsoo Kim
2012-10-29  2:09     ` Minchan Kim
2012-10-29  2:12   ` [PATCH 0/5] minor clean-up and optimize highmem related code Minchan Kim
2012-10-29 13:15     ` JoonSoo Kim
2012-10-31 17:11       ` JoonSoo Kim
2012-10-31 16:56 ` [PATCH v2 " Joonsoo Kim
2012-10-31 16:56   ` [PATCH v2 1/5] mm, highmem: use PKMAP_NR() to calculate an index of pkmap Joonsoo Kim
2012-10-31 16:56   ` [PATCH v2 2/5] mm, highmem: remove useless pool_lock Joonsoo Kim
2012-10-31 16:56   ` [PATCH v2 3/5] mm, highmem: remove page_address_pool list Joonsoo Kim
2012-10-31 16:56   ` [PATCH v2 4/5] mm, highmem: makes flush_all_zero_pkmaps() return index of first flushed entry Joonsoo Kim
2012-11-01  5:03     ` Minchan Kim
2012-11-02 19:07       ` JoonSoo Kim
2012-11-02 22:42         ` Minchan Kim
2012-11-13  0:30           ` JoonSoo Kim
2012-11-13 12:49             ` Minchan Kim
2012-11-13 14:12               ` JoonSoo Kim
2012-11-13 15:01                 ` Minchan Kim
2012-11-14 17:09                   ` JoonSoo Kim
2012-11-19 23:46                     ` Minchan Kim
2012-11-27 15:01                       ` JoonSoo Kim
2012-10-31 16:56   ` [PATCH v2 5/5] mm, highmem: get virtual address of the page using PKMAP_ADDR() Joonsoo Kim

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