File makedumpfile-exclude-compound-pages.patch of Package makedumpfile

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File makedumpfile-exclude-compound-pages.patch of Package makedumpfile (Revision 94b3803dc999e52bbf5152164262b98a)

Currently displaying revision 94b3803dc999e52bbf5152164262b98a , Show latest

From: Petr Tesarik <ptesarik@suse.cz>
Date: Fri Jun 13 11:57:03 2014 +0200
Subject: Treat compound pages as a single entity
References: bnc#873232
Patch-mainline: not yet

For a compound page, the head page determines whether the page should be
kept or excluded.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>

---
 makedumpfile.c |   57 +++++++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 43 insertions(+), 14 deletions(-)

--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -4652,6 +4652,7 @@ __exclude_unnecessary_pages(unsigned lon
 	unsigned char *pcache;
 	unsigned int _count, _mapcount = 0;
 	unsigned long flags, mapping, private = 0;
+	int nr_pages;
 
 	/*
 	 * If a multi-page exclusion is pending, do it first
@@ -4671,7 +4672,13 @@ __exclude_unnecessary_pages(unsigned lon
 	pfn_read_start = ULONGLONG_MAX;
 	pfn_read_end   = 0;
 
-	for (pfn = pfn_start; pfn < pfn_end; pfn++, mem_map += SIZE(page)) {
+	for (pfn = pfn_start; pfn < pfn_end; pfn += nr_pages, mem_map += nr_pages * SIZE(page)) {
+		unsigned long long *pfn_counter;
+
+		/*
+		 * Process one page by default.
+		 */
+		nr_pages = 1;
 
 		/*
 		 * If this pfn doesn't belong to target region, skip this pfn.
@@ -4723,18 +4730,32 @@ __exclude_unnecessary_pages(unsigned lon
 			private = ULONG(pcache + OFFSET(page.private));
 
 		/*
+		 * Check for compound pages.
+		 */
+		if (isCompoundHead(flags) && (pfn + 1 <= pfn_read_end)) {
+			unsigned char *ptail;
+			unsigned long order;
+
+			ptail = pcache + SIZE(page);
+			order = ULONG(ptail + OFFSET(page.lru) +
+				      OFFSET(list_head.prev));
+			if (order && order < sizeof(unsigned long) * 8 &&
+			    (pfn & ((1UL << order) - 1)) == 0 &&
+			    (OFFSET(page.private) == NOT_FOUND_STRUCTURE ||
+			     ULONG(ptail + OFFSET(page.private)) == mem_map)) {
+				nr_pages = 1UL << order;
+			}
+		}
+
+		/*
 		 * Exclude the free page managed by a buddy
 		 * Use buddy identification of free pages whether cyclic or not.
 		 */
 		if ((info->dump_level & DL_EXCLUDE_FREE)
 		    && info->page_is_buddy
 		    && info->page_is_buddy(flags, _mapcount, private, _count)) {
-			int nr_pages = 1 << private;
-
-			exclude_range(&pfn_free, pfn, pfn + nr_pages, cycle);
-
-			pfn += nr_pages - 1;
-			mem_map += (nr_pages - 1) * SIZE(page);
+			nr_pages = 1 << private;
+			pfn_counter = &pfn_free;
 		}
 		/*
 		 * Exclude the cache page without the private page.
@@ -4742,8 +4763,7 @@ __exclude_unnecessary_pages(unsigned lon
 		else if ((info->dump_level & DL_EXCLUDE_CACHE)
 		    && (isLRU(flags) || isSwapCache(flags))
 		    && !isPrivate(flags) && !isAnon(mapping)) {
-			if (clear_bit_on_2nd_bitmap_for_kernel(pfn, cycle))
-				pfn_cache++;
+			pfn_counter = &pfn_cache;
 		}
 		/*
 		 * Exclude the cache page with the private page.
@@ -4751,23 +4771,32 @@ __exclude_unnecessary_pages(unsigned lon
 		else if ((info->dump_level & DL_EXCLUDE_CACHE_PRI)
 		    && (isLRU(flags) || isSwapCache(flags))
 		    && !isAnon(mapping)) {
-			if (clear_bit_on_2nd_bitmap_for_kernel(pfn, cycle))
-				pfn_cache_private++;
+			pfn_counter = &pfn_cache_private;
 		}
 		/*
 		 * Exclude the data page of the user process.
 		 */
 		else if ((info->dump_level & DL_EXCLUDE_USER_DATA)
 		    && isAnon(mapping)) {
-			if (clear_bit_on_2nd_bitmap_for_kernel(pfn, cycle))
-				pfn_user++;
+			pfn_counter = &pfn_user;
 		}
 		/*
 		 * Exclude the hwpoison page.
 		 */
 		else if (isHWPOISON(flags)) {
+			pfn_counter = &pfn_hwpoison;
+		}
+		/*
+		 * Page not excluded
+		 */
+		else
+			continue;
+
+		if (nr_pages == 1) {
 			if (clear_bit_on_2nd_bitmap_for_kernel(pfn, cycle))
-				pfn_hwpoison++;
+				(*pfn_counter)++;
+		} else {
+			exclude_range(pfn_counter, pfn, pfn + nr_pages, cycle);
 		}
 	}
 	return TRUE;

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File makedumpfile-exclude-compound-pages.patch of Package makedumpfile (Revision 94b3803dc999e52bbf5152164262b98a)

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