Btrfs: use add_to_page_cache_lru, use __page_cache_alloc

Pagecache pages should be allocated with __page_cache_alloc, so they obey pagecache memory policies. add_to_page_cache_lru is exported, so it should be used. Benefits over using a private pagevec: neater code, 128 bytes fewer stack used, percpu lru ordering is preserved, and finally don't need to flush pagevec before returning so batching may be shared with other LRU insertions. Signed-off-by: Nick Piggin <npiggin@suse.de>: Signed-off-by: Chris Mason <chris.mason@oracle.com>

Btrfs: use add_to_page_cache_lru, use __page_cache_alloc
Pagecache pages should be allocated with __page_cache_alloc, so they obey pagecache memory policies. add_to_page_cache_lru is exported, so it should be used. Benefits over using a private pagevec: neater code, 128 bytes fewer stack used, percpu lru ordering is preserved, and finally don't need to flush pagevec before returning so batching may be shared with other LRU insertions. Signed-off-by: Nick Piggin <npiggin@suse.de>: Signed-off-by: Chris Mason <chris.mason@oracle.com>
Nick Piggin · Chris Mason
1 parent 0cad8a1130
Showing 2 changed files with 5 additions and 32 deletions Side-by-side Diff
fs/btrfs/compression.c
fs/btrfs/extent_io.c
@@ -31,7 +31,6 @@
 #include <linux/swap.h>
 #include <linux/writeback.h>
 #include <linux/bit_spinlock.h>
-#include <linux/pagevec.h>
 #include "compat.h"
 #include "ctree.h"
 #include "disk-io.h"
@@ -445,7 +444,6 @@
 	unsigned long nr_pages = 0;
 	struct extent_map *em;
 	struct address_space *mapping = inode->i_mapping;
-	struct pagevec pvec;
 	struct extent_map_tree *em_tree;
 	struct extent_io_tree *tree;
 	u64 end;
@@ -461,7 +459,6 @@
  
 	end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
  
-	pagevec_init(&pvec, 0);
 	while (last_offset < compressed_end) {
 		page_index = last_offset >> PAGE_CACHE_SHIFT;
  
  
  
@@ -478,26 +475,17 @@
 			goto next;
 		}
  
-		page = alloc_page(mapping_gfp_mask(mapping) & ~__GFP_FS);
+		page = __page_cache_alloc(mapping_gfp_mask(mapping) &
+								~__GFP_FS);
 		if (!page)
 			break;
  
-		page->index = page_index;
-		/*
-		 * what we want to do here is call add_to_page_cache_lru,
-		 * but that isn't exported, so we reproduce it here
-		 */
-		if (add_to_page_cache(page, mapping,
-				      page->index, GFP_NOFS)) {
+		if (add_to_page_cache_lru(page, mapping, page_index,
+								GFP_NOFS)) {
 			page_cache_release(page);
 			goto next;
 		}
  
-		/* open coding of lru_cache_add, also not exported */
-		page_cache_get(page);
-		if (!pagevec_add(&pvec, page))
-			__pagevec_lru_add_file(&pvec);
-
 		end = last_offset + PAGE_CACHE_SIZE - 1;
 		/*
 		 * at this point, we have a locked page in the page cache
@@ -551,8 +539,6 @@
 next:
 		last_offset += PAGE_CACHE_SIZE;
 	}
-	if (pagevec_count(&pvec))
-		__pagevec_lru_add_file(&pvec);
 	return 0;
 }
  
@@ -2679,33 +2679,20 @@
 {
 	struct bio *bio = NULL;
 	unsigned page_idx;
-	struct pagevec pvec;
 	unsigned long bio_flags = 0;
  
-	pagevec_init(&pvec, 0);
 	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 		struct page *page = list_entry(pages->prev, struct page, lru);
  
 		prefetchw(&page->flags);
 		list_del(&page->lru);
-		/*
-		 * what we want to do here is call add_to_page_cache_lru,
-		 * but that isn't exported, so we reproduce it here
-		 */
-		if (!add_to_page_cache(page, mapping,
+		if (!add_to_page_cache_lru(page, mapping,
 					page->index, GFP_KERNEL)) {
-
-			/* open coding of lru_cache_add, also not exported */
-			page_cache_get(page);
-			if (!pagevec_add(&pvec, page))
-				__pagevec_lru_add_file(&pvec);
 			__extent_read_full_page(tree, page, get_extent,
 						&bio, 0, &bio_flags);
 		}
 		page_cache_release(page);
 	}
-	if (pagevec_count(&pvec))
-		__pagevec_lru_add_file(&pvec);
 	BUG_ON(!list_empty(pages));
 	if (bio)
 		submit_one_bio(READ, bio, 0, bio_flags);
...	...	@@ -31,7 +31,6 @@
31	31	#include <linux/swap.h>
32	32	#include <linux/writeback.h>
33	33	#include <linux/bit_spinlock.h>
34		-#include <linux/pagevec.h>
35	34	#include "compat.h"
36	35	#include "ctree.h"
37	36	#include "disk-io.h"
...	...	@@ -445,7 +444,6 @@
445	444	unsigned long nr_pages = 0;
446	445	struct extent_map *em;
447	446	struct address_space *mapping = inode->i_mapping;
448		- struct pagevec pvec;
449	447	struct extent_map_tree *em_tree;
450	448	struct extent_io_tree *tree;
451	449	u64 end;
...	...	@@ -461,7 +459,6 @@
461	459
462	460	end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
463	461
464		- pagevec_init(&pvec, 0);
465	462	while (last_offset < compressed_end) {
466	463	page_index = last_offset >> PAGE_CACHE_SHIFT;
467	464
468	465
469	466
...	...	@@ -478,26 +475,17 @@
478	475	goto next;
479	476	}
480	477
481		- page = alloc_page(mapping_gfp_mask(mapping) & ~__GFP_FS);
	478	+ page = __page_cache_alloc(mapping_gfp_mask(mapping) &
	479	+ ~__GFP_FS);
482	480	if (!page)
483	481	break;
484	482
485		- page->index = page_index;
486		- /*
487		- * what we want to do here is call add_to_page_cache_lru,
488		- * but that isn't exported, so we reproduce it here
489		- */
490		- if (add_to_page_cache(page, mapping,
491		- page->index, GFP_NOFS)) {
	483	+ if (add_to_page_cache_lru(page, mapping, page_index,
	484	+ GFP_NOFS)) {
492	485	page_cache_release(page);
493	486	goto next;
494	487	}
495	488
496		- /* open coding of lru_cache_add, also not exported */
497		- page_cache_get(page);
498		- if (!pagevec_add(&pvec, page))
499		- __pagevec_lru_add_file(&pvec);
500		-
501	489	end = last_offset + PAGE_CACHE_SIZE - 1;
502	490	/*
503	491	* at this point, we have a locked page in the page cache
...	...	@@ -551,8 +539,6 @@
551	539	next:
552	540	last_offset += PAGE_CACHE_SIZE;
553	541	}
554		- if (pagevec_count(&pvec))
555		- __pagevec_lru_add_file(&pvec);
556	542	return 0;
557	543	}
558	544
...	...	@@ -2679,33 +2679,20 @@
2679	2679	{
2680	2680	struct bio *bio = NULL;
2681	2681	unsigned page_idx;
2682		- struct pagevec pvec;
2683	2682	unsigned long bio_flags = 0;
2684	2683
2685		- pagevec_init(&pvec, 0);
2686	2684	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
2687	2685	struct page *page = list_entry(pages->prev, struct page, lru);
2688	2686
2689	2687	prefetchw(&page->flags);
2690	2688	list_del(&page->lru);
2691		- /*
2692		- * what we want to do here is call add_to_page_cache_lru,
2693		- * but that isn't exported, so we reproduce it here
2694		- */
2695		- if (!add_to_page_cache(page, mapping,
	2689	+ if (!add_to_page_cache_lru(page, mapping,
2696	2690	page->index, GFP_KERNEL)) {
2697		-
2698		- /* open coding of lru_cache_add, also not exported */
2699		- page_cache_get(page);
2700		- if (!pagevec_add(&pvec, page))
2701		- __pagevec_lru_add_file(&pvec);
2702	2691	__extent_read_full_page(tree, page, get_extent,
2703	2692	&bio, 0, &bio_flags);
2704	2693	}
2705	2694	page_cache_release(page);
2706	2695	}
2707		- if (pagevec_count(&pvec))
2708		- __pagevec_lru_add_file(&pvec);
2709	2696	BUG_ON(!list_empty(pages));
2710	2697	if (bio)
2711	2698	submit_one_bio(READ, bio, 0, bio_flags);