[PATCH 2/2] f2fs: compress: delay temp page allocation

[Chao Yu <yuchao0@huawei.com>]

Currently, we allocate temp pages which is used to pad hole in
cluster during read IO submission, it may take long time before
releasing them in f2fs_decompress_pages(), since they are only
used as temp output buffer in decompression context, so let's
just do the allocation in that context to reduce time of memory
pool resource occupation.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
 fs/f2fs/compress.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index a20c9f3272af..337a272d7112 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -670,6 +670,7 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity)
 	const struct f2fs_compress_ops *cops =
 			f2fs_cops[fi->i_compress_algorithm];
 	int ret;
+	int i;
 
 	dec_page_count(sbi, F2FS_RD_DATA);
 
@@ -688,6 +689,22 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity)
 		goto out_free_dic;
 	}
 
+	dic->tpages = f2fs_kzalloc(sbi, sizeof(struct page *) *
+					dic->cluster_size, GFP_NOFS);
+	if (!dic->tpages)
+		goto out_free_dic;
+
+	for (i = 0; i < dic->cluster_size; i++) {
+		if (dic->rpages[i]) {
+			dic->tpages[i] = dic->rpages[i];
+			continue;
+		}
+
+		dic->tpages[i] = f2fs_compress_alloc_page();
+		if (!dic->tpages[i])
+			goto out_free_dic;
+	}
+
 	if (cops->init_decompress_ctx) {
 		ret = cops->init_decompress_ctx(dic);
 		if (ret)
@@ -1449,22 +1466,6 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
 		dic->cpages[i] = page;
 	}
 
-	dic->tpages = f2fs_kzalloc(sbi, sizeof(struct page *) *
-					dic->cluster_size, GFP_NOFS);
-	if (!dic->tpages)
-		goto out_free;
-
-	for (i = 0; i < dic->cluster_size; i++) {
-		if (cc->rpages[i]) {
-			dic->tpages[i] = cc->rpages[i];
-			continue;
-		}
-
-		dic->tpages[i] = f2fs_compress_alloc_page();
-		if (!dic->tpages[i])
-			goto out_free;
-	}
-
 	return dic;
 
 out_free:
-- 
2.26.2