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Date: Wed, 8 Apr 2020 19:56:05 +0800
From: Chao Yu <yuchao0@...wei.com>
To: <jaegeuk@...nel.org>
CC: <linux-f2fs-devel@...ts.sourceforge.net>,
<linux-kernel@...r.kernel.org>, <chao@...nel.org>,
Chao Yu <yuchao0@...wei.com>
Subject: [PATCH] f2fs: introduce mempool for {,de}compress intermediate page allocation
If compression feature is on, in scenario of no enough free memory,
page refault ratio is higher than before, the root cause is:
- {,de}compression flow needs to allocate intermediate pages to store
compressed data in cluster, so during their allocation, vm may reclaim
mmaped pages.
- if above reclaimed pages belong to compressed cluster, during its
refault, it may cause more intermediate pages allocation, result in
reclaiming more mmaped pages.
So this patch introduces a mempool for intermediate page allocation,
in order to avoid high refault ratio, by default, number of
preallocated page in pool is 512, user can change the number by
assigning 'num_compress_pages' parameter during module initialization.
Signed-off-by: Chao Yu <yuchao0@...wei.com>
---
fs/f2fs/compress.c | 64 ++++++++++++++++++++++++++++++----------------
fs/f2fs/f2fs.h | 4 +++
fs/f2fs/super.c | 6 +++++
3 files changed, 52 insertions(+), 22 deletions(-)
diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 25d72e18ac30..ac265c6c40b5 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -65,15 +65,6 @@ static void f2fs_set_compressed_page(struct page *page,
page->mapping = inode->i_mapping;
}
-static void f2fs_put_compressed_page(struct page *page)
-{
- set_page_private(page, (unsigned long)NULL);
- ClearPagePrivate(page);
- page->mapping = NULL;
- unlock_page(page);
- put_page(page);
-}
-
static void f2fs_drop_rpages(struct compress_ctx *cc, int len, bool unlock)
{
int i;
@@ -476,17 +467,47 @@ bool f2fs_is_compress_backend_ready(struct inode *inode)
return f2fs_cops[F2FS_I(inode)->i_compress_algorithm];
}
-static struct page *f2fs_grab_page(void)
+static mempool_t *compress_page_pool = NULL;
+int num_compress_pages = 512;
+module_param(num_compress_pages, uint, 0444);
+MODULE_PARM_DESC(num_compress_pages,
+ "Number of intermediate compress pages to preallocate");
+
+int f2fs_init_compress_mempool(void)
+{
+ compress_page_pool = mempool_create_page_pool(num_compress_pages, 0);
+ if (!compress_page_pool)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void f2fs_destroy_compress_mempool(void)
+{
+ mempool_destroy(compress_page_pool);
+}
+
+static struct page *f2fs_compress_alloc_page(void)
{
struct page *page;
- page = alloc_page(GFP_NOFS);
- if (!page)
- return NULL;
+ page = mempool_alloc(compress_page_pool, GFP_NOFS);
lock_page(page);
+
return page;
}
+void f2fs_compress_free_page(struct page *page)
+{
+ if (!page)
+ return;
+ set_page_private(page, (unsigned long)NULL);
+ ClearPagePrivate(page);
+ page->mapping = NULL;
+ unlock_page(page);
+ mempool_free(page, compress_page_pool);
+}
+
static int f2fs_compress_pages(struct compress_ctx *cc)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
@@ -516,7 +537,7 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
}
for (i = 0; i < cc->nr_cpages; i++) {
- cc->cpages[i] = f2fs_grab_page();
+ cc->cpages[i] = f2fs_compress_alloc_page();
if (!cc->cpages[i]) {
ret = -ENOMEM;
goto out_free_cpages;
@@ -561,7 +582,7 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
vunmap(cc->rbuf);
for (i = nr_cpages; i < cc->nr_cpages; i++) {
- f2fs_put_compressed_page(cc->cpages[i]);
+ f2fs_compress_free_page(cc->cpages[i]);
cc->cpages[i] = NULL;
}
@@ -581,7 +602,7 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
out_free_cpages:
for (i = 0; i < cc->nr_cpages; i++) {
if (cc->cpages[i])
- f2fs_put_compressed_page(cc->cpages[i]);
+ f2fs_compress_free_page(cc->cpages[i]);
}
kfree(cc->cpages);
cc->cpages = NULL;
@@ -1181,7 +1202,7 @@ void f2fs_compress_write_end_io(struct bio *bio, struct page *page)
if (unlikely(bio->bi_status))
mapping_set_error(cic->inode->i_mapping, -EIO);
- f2fs_put_compressed_page(page);
+ f2fs_compress_free_page(page);
dec_page_count(sbi, F2FS_WB_DATA);
@@ -1342,7 +1363,7 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
for (i = 0; i < dic->nr_cpages; i++) {
struct page *page;
- page = f2fs_grab_page();
+ page = f2fs_compress_alloc_page();
if (!page)
goto out_free;
@@ -1362,7 +1383,7 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
continue;
}
- dic->tpages[i] = f2fs_grab_page();
+ dic->tpages[i] = f2fs_compress_alloc_page();
if (!dic->tpages[i])
goto out_free;
}
@@ -1384,8 +1405,7 @@ void f2fs_free_dic(struct decompress_io_ctx *dic)
continue;
if (!dic->tpages[i])
continue;
- unlock_page(dic->tpages[i]);
- put_page(dic->tpages[i]);
+ f2fs_compress_free_page(dic->tpages[i]);
}
kfree(dic->tpages);
}
@@ -1394,7 +1414,7 @@ void f2fs_free_dic(struct decompress_io_ctx *dic)
for (i = 0; i < dic->nr_cpages; i++) {
if (!dic->cpages[i])
continue;
- f2fs_put_compressed_page(dic->cpages[i]);
+ f2fs_compress_free_page(dic->cpages[i]);
}
kfree(dic->cpages);
}
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ed354af78966..e0d520f2c142 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3798,6 +3798,8 @@ bool f2fs_compress_write_end(struct inode *inode, void *fsdata,
int f2fs_truncate_partial_cluster(struct inode *inode, u64 from, bool lock);
void f2fs_compress_write_end_io(struct bio *bio, struct page *page);
bool f2fs_is_compress_backend_ready(struct inode *inode);
+int f2fs_init_compress_mempool(void);
+void f2fs_destroy_compress_mempool(void);
void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity);
bool f2fs_cluster_is_empty(struct compress_ctx *cc);
bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
@@ -3831,6 +3833,8 @@ static inline struct page *f2fs_compress_control_page(struct page *page)
WARN_ON_ONCE(1);
return ERR_PTR(-EINVAL);
}
+static inline int f2fs_init_compress_mempool(void) { return 0; }
+static inline void f2fs_destroy_compress_mempool(void) { }
#endif
static inline void set_compress_context(struct inode *inode)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index b83b17b54a0a..9ad927c4d259 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3889,7 +3889,12 @@ static int __init init_f2fs_fs(void)
err = f2fs_init_bioset();
if (err)
goto free_bio_enrty_cache;
+ err = f2fs_init_compress_mempool();
+ if (err)
+ goto free_bioset;
return 0;
+free_bioset:
+ f2fs_destroy_bioset();
free_bio_enrty_cache:
f2fs_destroy_bio_entry_cache();
free_post_read:
@@ -3917,6 +3922,7 @@ static int __init init_f2fs_fs(void)
static void __exit exit_f2fs_fs(void)
{
+ f2fs_destroy_compress_mempool();
f2fs_destroy_bioset();
f2fs_destroy_bio_entry_cache();
f2fs_destroy_post_read_processing();
--
2.18.0.rc1
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