f2fs: use onstack pages instead of pvec

Since pvec have 15 pages, it not a multiple of 4, when write compressed
pages, write in 64K as a unit, it will call pagevec_lookup_range_tag
agagin, sometimes this will take a lot of time.
Use onstack pages instead of pvec to mitigate this problem.
Signed-off-by: Fengnan Chang <fengnanchang@gmail.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/compress.c

@@ -841,10 +841,10 @@ bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index)
 	return is_page_in_cluster(cc, index);
 }
 
-bool f2fs_all_cluster_page_ready(struct compress_ctx *cc, struct pagevec *pvec,
+bool f2fs_all_cluster_page_ready(struct compress_ctx *cc, struct page **pages,
 				int index, int nr_pages, bool uptodate)
 {
-	unsigned long pgidx = pvec->pages[index]->index;
+	unsigned long pgidx = pages[index]->index;
 	int i = uptodate ? 0 : 1;
 
 	/*
@@ -858,9 +858,9 @@ bool f2fs_all_cluster_page_ready(struct compress_ctx *cc, struct pagevec *pvec,
 		return false;
 
 	for (; i < cc->cluster_size; i++) {
-		if (pvec->pages[index + i]->index != pgidx + i)
+		if (pages[index + i]->index != pgidx + i)
 			return false;
-		if (uptodate && !PageUptodate(pvec->pages[index + i]))
+		if (uptodate && !PageUptodate(pages[index + i]))
 			return false;
 	}
 

fs/f2fs/data.c

@@ -2916,7 +2916,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 {
 	int ret = 0;
 	int done = 0, retry = 0;
-	struct pagevec pvec;
+	struct page *pages[F2FS_ONSTACK_PAGES];
 	struct f2fs_sb_info *sbi = F2FS_M_SB(mapping);
 	struct bio *bio = NULL;
 	sector_t last_block;
@@ -2947,8 +2947,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 	int submitted = 0;
 	int i;
 
-	pagevec_init(&pvec);
-
 	if (get_dirty_pages(mapping->host) <=
 				SM_I(F2FS_M_SB(mapping))->min_hot_blocks)
 		set_inode_flag(mapping->host, FI_HOT_DATA);
@@ -2974,13 +2972,13 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 		tag_pages_for_writeback(mapping, index, end);
 	done_index = index;
 	while (!done && !retry && (index <= end)) {
-		nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
-				tag);
+		nr_pages = find_get_pages_range_tag(mapping, &index, end,
+				tag, F2FS_ONSTACK_PAGES, pages);
 		if (nr_pages == 0)
 			break;
 
 		for (i = 0; i < nr_pages; i++) {
-			struct page *page = pvec.pages[i];
+			struct page *page = pages[i];
 			bool need_readd;
 readd:
 			need_readd = false;
@@ -3012,7 +3010,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 					goto lock_page;
 
 				if (f2fs_all_cluster_page_ready(&cc,
-					&pvec, i, nr_pages, true))
+					pages, i, nr_pages, true))
 					goto lock_page;
 
 				ret2 = f2fs_prepare_compress_overwrite(
@@ -3026,7 +3024,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 					(!f2fs_compress_write_end(inode,
 						fsdata, page->index, 1) ||
 					 !f2fs_all_cluster_page_ready(&cc,
-						&pvec, i, nr_pages, false))) {
+						pages, i, nr_pages, false))) {
 					retry = 1;
 					break;
 				}
@@ -3116,7 +3114,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 			if (need_readd)
 				goto readd;
 		}
-		pagevec_release(&pvec);
+		release_pages(pages, nr_pages);
 		cond_resched();
 	}
 #ifdef CONFIG_F2FS_FS_COMPRESSION

fs/f2fs/f2fs.h

@@ -598,6 +598,8 @@ enum {
 #define RECOVERY_MAX_RA_BLOCKS		BIO_MAX_VECS
 #define RECOVERY_MIN_RA_BLOCKS		1
 
+#define F2FS_ONSTACK_PAGES	16	/* nr of onstack pages */
+
 struct rb_entry {
 	struct rb_node rb_node;		/* rb node located in rb-tree */
 	union {
@@ -4198,7 +4200,7 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed,
 				block_t blkaddr, bool in_task);
 bool f2fs_cluster_is_empty(struct compress_ctx *cc);
 bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
-bool f2fs_all_cluster_page_ready(struct compress_ctx *cc, struct pagevec *pvec,
+bool f2fs_all_cluster_page_ready(struct compress_ctx *cc, struct page **pages,
 				int index, int nr_pages, bool uptodate);
 bool f2fs_sanity_check_cluster(struct dnode_of_data *dn);
 void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page *page);