f2fs: compress: introduce page array slab cache

Add a per-sbi slab cache "f2fs_page_array_entry-%u:%u" for memory
allocation of page pointer array in compress context.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: Fix wrong memory allocation]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/compress.c

@@ -17,6 +17,30 @@
 #include "node.h"
 #include <trace/events/f2fs.h>
 
+static void *page_array_alloc(struct inode *inode, int nr)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	unsigned int size = sizeof(struct page *) * nr;
+
+	if (likely(size <= sbi->page_array_slab_size))
+		return kmem_cache_zalloc(sbi->page_array_slab, GFP_NOFS);
+	return f2fs_kzalloc(sbi, size, GFP_NOFS);
+}
+
+static void page_array_free(struct inode *inode, void *pages, int nr)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	unsigned int size = sizeof(struct page *) * nr;
+
+	if (!pages)
+		return;
+
+	if (likely(size <= sbi->page_array_slab_size))
+		kmem_cache_free(sbi->page_array_slab, pages);
+	else
+		kfree(pages);
+}
+
 struct f2fs_compress_ops {
 	int (*init_compress_ctx)(struct compress_ctx *cc);
 	void (*destroy_compress_ctx)(struct compress_ctx *cc);
@@ -130,19 +154,16 @@ struct page *f2fs_compress_control_page(struct page *page)
 
 int f2fs_init_compress_ctx(struct compress_ctx *cc)
 {
-	struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
-
 	if (cc->nr_rpages)
 		return 0;
 
-	cc->rpages = f2fs_kzalloc(sbi, sizeof(struct page *) <<
+	cc->rpages = page_array_alloc(cc->inode, cc->cluster_size);
-					cc->log_cluster_size, GFP_NOFS);
 	return cc->rpages ? 0 : -ENOMEM;
 }
 
 void f2fs_destroy_compress_ctx(struct compress_ctx *cc)
 {
-	kfree(cc->rpages);
+	page_array_free(cc->inode, cc->rpages, cc->cluster_size);
 	cc->rpages = NULL;
 	cc->nr_rpages = 0;
 	cc->nr_cpages = 0;
@@ -573,11 +594,11 @@ static void *f2fs_vmap(struct page **pages, unsigned int count)
 
 static int f2fs_compress_pages(struct compress_ctx *cc)
 {
-	struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
 	struct f2fs_inode_info *fi = F2FS_I(cc->inode);
 	const struct f2fs_compress_ops *cops =
 				f2fs_cops[fi->i_compress_algorithm];
-	unsigned int max_len, nr_cpages;
+	unsigned int max_len, new_nr_cpages;
+	struct page **new_cpages;
 	int i, ret;
 
 	trace_f2fs_compress_pages_start(cc->inode, cc->cluster_idx,
@@ -592,8 +613,7 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
 	max_len = COMPRESS_HEADER_SIZE + cc->clen;
 	cc->nr_cpages = DIV_ROUND_UP(max_len, PAGE_SIZE);
 
-	cc->cpages = f2fs_kzalloc(sbi, sizeof(struct page *) *
+	cc->cpages = page_array_alloc(cc->inode, cc->nr_cpages);
-					cc->nr_cpages, GFP_NOFS);
 	if (!cc->cpages) {
 		ret = -ENOMEM;
 		goto destroy_compress_ctx;
@@ -635,16 +655,28 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
 	for (i = 0; i < COMPRESS_DATA_RESERVED_SIZE; i++)
 		cc->cbuf->reserved[i] = cpu_to_le32(0);
 
-	nr_cpages = DIV_ROUND_UP(cc->clen + COMPRESS_HEADER_SIZE, PAGE_SIZE);
+	new_nr_cpages = DIV_ROUND_UP(cc->clen + COMPRESS_HEADER_SIZE, PAGE_SIZE);
+
+	/* Now we're going to cut unnecessary tail pages */
+	new_cpages = page_array_alloc(cc->inode, new_nr_cpages);
+	if (!new_cpages) {
+		ret = -ENOMEM;
+		goto out_vunmap_cbuf;
+	}
 
 	/* zero out any unused part of the last page */
 	memset(&cc->cbuf->cdata[cc->clen], 0,
-	       (nr_cpages * PAGE_SIZE) - (cc->clen + COMPRESS_HEADER_SIZE));
+			(new_nr_cpages * PAGE_SIZE) -
+			(cc->clen + COMPRESS_HEADER_SIZE));
 
 	vm_unmap_ram(cc->cbuf, cc->nr_cpages);
 	vm_unmap_ram(cc->rbuf, cc->cluster_size);
 
-	for (i = nr_cpages; i < cc->nr_cpages; i++) {
+	for (i = 0; i < cc->nr_cpages; i++) {
+		if (i < new_nr_cpages) {
+			new_cpages[i] = cc->cpages[i];
+			continue;
+		}
 		f2fs_compress_free_page(cc->cpages[i]);
 		cc->cpages[i] = NULL;
 	}
@@ -652,7 +684,9 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
 	if (cops->destroy_compress_ctx)
 		cops->destroy_compress_ctx(cc);
 
-	cc->nr_cpages = nr_cpages;
+	page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
+	cc->cpages = new_cpages;
+	cc->nr_cpages = new_nr_cpages;
 
 	trace_f2fs_compress_pages_end(cc->inode, cc->cluster_idx,
 							cc->clen, ret);
@@ -667,7 +701,7 @@ out_free_cpages:
 		if (cc->cpages[i])
 			f2fs_compress_free_page(cc->cpages[i]);
 	}
-	kfree(cc->cpages);
+	page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
 	cc->cpages = NULL;
 destroy_compress_ctx:
 	if (cops->destroy_compress_ctx)
@@ -706,8 +740,7 @@ 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->tpages = page_array_alloc(dic->inode, dic->cluster_size);
-					dic->cluster_size, GFP_NOFS);
 	if (!dic->tpages) {
 		ret = -ENOMEM;
 		goto out_free_dic;
@@ -1046,6 +1079,7 @@ bool f2fs_compress_write_end(struct inode *inode, void *fsdata,
 
 {
 	struct compress_ctx cc = {
+		.inode = inode,
 		.log_cluster_size = F2FS_I(inode)->i_log_cluster_size,
 		.cluster_size = F2FS_I(inode)->i_cluster_size,
 		.rpages = fsdata,
@@ -1149,7 +1183,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
 		 */
 		down_read(&sbi->node_write);
 	} else if (!f2fs_trylock_op(sbi)) {
-		return -EAGAIN;
+		goto out_free;
 	}
 
 	set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
@@ -1179,8 +1213,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
 	cic->magic = F2FS_COMPRESSED_PAGE_MAGIC;
 	cic->inode = inode;
 	atomic_set(&cic->pending_pages, cc->nr_cpages);
-	cic->rpages = f2fs_kzalloc(sbi, sizeof(struct page *) <<
+	cic->rpages = page_array_alloc(cc->inode, cc->cluster_size);
-			cc->log_cluster_size, GFP_NOFS);
 	if (!cic->rpages)
 		goto out_put_cic;
 
@@ -1274,11 +1307,13 @@ unlock_continue:
 	spin_unlock(&fi->i_size_lock);
 
 	f2fs_put_rpages(cc);
+	page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
+	cc->cpages = NULL;
 	f2fs_destroy_compress_ctx(cc);
 	return 0;
 
 out_destroy_crypt:
-	kfree(cic->rpages);
+	page_array_free(cc->inode, cic->rpages, cc->cluster_size);
 
 	for (--i; i >= 0; i--)
 		fscrypt_finalize_bounce_page(&cc->cpages[i]);
@@ -1296,6 +1331,9 @@ out_unlock_op:
 		up_read(&sbi->node_write);
 	else
 		f2fs_unlock_op(sbi);
+out_free:
+	page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
+	cc->cpages = NULL;
 	return -EAGAIN;
 }
 
@@ -1322,7 +1360,7 @@ void f2fs_compress_write_end_io(struct bio *bio, struct page *page)
 		end_page_writeback(cic->rpages[i]);
 	}
 
-	kfree(cic->rpages);
+	page_array_free(cic->inode, cic->rpages, cic->nr_rpages);
 	kfree(cic);
 }
 
@@ -1419,8 +1457,6 @@ int f2fs_write_multi_pages(struct compress_ctx *cc,
 
 		err = f2fs_write_compressed_pages(cc, submitted,
 							wbc, io_type);
-		kfree(cc->cpages);
-		cc->cpages = NULL;
 		if (!err)
 			return 0;
 		f2fs_bug_on(F2FS_I_SB(cc->inode), err != -EAGAIN);
@@ -1446,8 +1482,7 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
 	if (!dic)
 		return ERR_PTR(-ENOMEM);
 
-	dic->rpages = f2fs_kzalloc(sbi, sizeof(struct page *) <<
+	dic->rpages = page_array_alloc(cc->inode, cc->cluster_size);
-			cc->log_cluster_size, GFP_NOFS);
 	if (!dic->rpages) {
 		kfree(dic);
 		return ERR_PTR(-ENOMEM);
@@ -1466,8 +1501,7 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
 		dic->rpages[i] = cc->rpages[i];
 	dic->nr_rpages = cc->cluster_size;
 
-	dic->cpages = f2fs_kzalloc(sbi, sizeof(struct page *) *
+	dic->cpages = page_array_alloc(dic->inode, dic->nr_cpages);
-					dic->nr_cpages, GFP_NOFS);
 	if (!dic->cpages)
 		goto out_free;
 
@@ -1502,7 +1536,7 @@ void f2fs_free_dic(struct decompress_io_ctx *dic)
 				continue;
 			f2fs_compress_free_page(dic->tpages[i]);
 		}
-		kfree(dic->tpages);
+		page_array_free(dic->inode, dic->tpages, dic->cluster_size);
 	}
 
 	if (dic->cpages) {
@@ -1511,10 +1545,10 @@ void f2fs_free_dic(struct decompress_io_ctx *dic)
 				continue;
 			f2fs_compress_free_page(dic->cpages[i]);
 		}
-		kfree(dic->cpages);
+		page_array_free(dic->inode, dic->cpages, dic->nr_cpages);
 	}
 
-	kfree(dic->rpages);
+	page_array_free(dic->inode, dic->rpages, dic->nr_rpages);
 	kfree(dic);
 }
 
@@ -1543,3 +1577,25 @@ unlock:
 		unlock_page(rpage);
 	}
 }
+
+int f2fs_init_page_array_cache(struct f2fs_sb_info *sbi)
+{
+	dev_t dev = sbi->sb->s_bdev->bd_dev;
+	char slab_name[32];
+
+	sprintf(slab_name, "f2fs_page_array_entry-%u:%u", MAJOR(dev), MINOR(dev));
+
+	sbi->page_array_slab_size = sizeof(struct page *) <<
+					F2FS_OPTION(sbi).compress_log_size;
+
+	sbi->page_array_slab = f2fs_kmem_cache_create(slab_name,
+					sbi->page_array_slab_size);
+	if (!sbi->page_array_slab)
+		return -ENOMEM;
+	return 0;
+}
+
+void f2fs_destroy_page_array_cache(struct f2fs_sb_info *sbi)
+{
+	kmem_cache_destroy(sbi->page_array_slab);
+}

fs/f2fs/f2fs.h

@@ -1622,6 +1622,11 @@ struct f2fs_sb_info {
 
 	struct kmem_cache *inline_xattr_slab;	/* inline xattr entry */
 	unsigned int inline_xattr_slab_size;	/* default inline xattr slab size */
+
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+	struct kmem_cache *page_array_slab;	/* page array entry */
+	unsigned int page_array_slab_size;	/* default page array slab size */
+#endif
 };
 
 struct f2fs_private_dio {
@@ -3929,6 +3934,8 @@ void f2fs_decompress_end_io(struct page **rpages,
 int f2fs_init_compress_ctx(struct compress_ctx *cc);
 void f2fs_destroy_compress_ctx(struct compress_ctx *cc);
 void f2fs_init_compress_info(struct f2fs_sb_info *sbi);
+int f2fs_init_page_array_cache(struct f2fs_sb_info *sbi);
+void f2fs_destroy_page_array_cache(struct f2fs_sb_info *sbi);
 #else
 static inline bool f2fs_is_compressed_page(struct page *page) { return false; }
 static inline bool f2fs_is_compress_backend_ready(struct inode *inode)
@@ -3945,6 +3952,8 @@ static inline struct page *f2fs_compress_control_page(struct page *page)
 }
 static inline int f2fs_init_compress_mempool(void) { return 0; }
 static inline void f2fs_destroy_compress_mempool(void) { }
+static inline int f2fs_init_page_array_cache(struct f2fs_sb_info *sbi) { return 0; }
+static inline void f2fs_destroy_page_array_cache(struct f2fs_sb_info *sbi) { }
 #endif
 
 static inline void set_compress_context(struct inode *inode)

fs/f2fs/super.c

@@ -1288,6 +1288,7 @@ static void f2fs_put_super(struct super_block *sb)
 	kfree(sbi->raw_super);
 
 	destroy_device_list(sbi);
+	f2fs_destroy_page_array_cache(sbi);
 	f2fs_destroy_xattr_caches(sbi);
 	mempool_destroy(sbi->write_io_dummy);
 #ifdef CONFIG_QUOTA
@@ -3620,13 +3621,16 @@ try_onemore:
 	err = f2fs_init_xattr_caches(sbi);
 	if (err)
 		goto free_io_dummy;
+	err = f2fs_init_page_array_cache(sbi);
+	if (err)
+		goto free_xattr_cache;
 
 	/* get an inode for meta space */
 	sbi->meta_inode = f2fs_iget(sb, F2FS_META_INO(sbi));
 	if (IS_ERR(sbi->meta_inode)) {
 		f2fs_err(sbi, "Failed to read F2FS meta data inode");
 		err = PTR_ERR(sbi->meta_inode);
-		goto free_xattr_cache;
+		goto free_page_array_cache;
 	}
 
 	err = f2fs_get_valid_checkpoint(sbi);
@@ -3902,6 +3906,8 @@ free_meta_inode:
 	make_bad_inode(sbi->meta_inode);
 	iput(sbi->meta_inode);
 	sbi->meta_inode = NULL;
+free_page_array_cache:
+	f2fs_destroy_page_array_cache(sbi);
 free_xattr_cache:
 	f2fs_destroy_xattr_caches(sbi);
 free_io_dummy: