Re: [f2fs-dev] [PATCH 1/2] f2fs: write small sized IO to hot log

From: heyunlei
Date: Thu Mar 30 2017 - 23:38:33 EST


Hi Jaegeuk,

On 2017/3/30 4:48, Jaegeuk Kim wrote:
It would better split small and large IOs separately in order to get more
consecutive big writes.

The default threshold is set to 64KB, but configurable by sysfs/min_hot_blocks.

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/data.c | 9 +++++++++
fs/f2fs/f2fs.h | 2 ++
fs/f2fs/segment.c | 13 ++++++-------
fs/f2fs/segment.h | 1 +
fs/f2fs/super.c | 2 ++
5 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 090413236b27..8f36080b47c4 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1432,6 +1432,8 @@ static int __write_data_page(struct page *page, bool *submitted,
need_balance_fs = true;
else if (has_not_enough_free_secs(sbi, 0, 0))
goto redirty_out;
+ else
+ set_inode_flag(inode, FI_HOT_DATA);

Why here we need this, can you explain more about this?

Thanks.


err = -EAGAIN;
if (f2fs_has_inline_data(inode)) {
@@ -1457,6 +1459,7 @@ static int __write_data_page(struct page *page, bool *submitted,
if (wbc->for_reclaim) {
f2fs_submit_merged_bio_cond(sbi, inode, 0, page->index,
DATA, WRITE);
+ clear_inode_flag(inode, FI_HOT_DATA);
remove_dirty_inode(inode);
submitted = NULL;
}
@@ -1511,6 +1514,12 @@ static int f2fs_write_cache_pages(struct address_space *mapping,

pagevec_init(&pvec, 0);

+ if (get_dirty_pages(mapping->host) <=
+ SM_I(F2FS_M_SB(mapping))->min_hot_blocks)
+ set_inode_flag(mapping->host, FI_HOT_DATA);
+ else
+ clear_inode_flag(mapping->host, FI_HOT_DATA);
+
if (wbc->range_cyclic) {
writeback_index = mapping->writeback_index; /* prev offset */
index = writeback_index;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 5a49518ee786..32d6f674c114 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -678,6 +678,7 @@ struct f2fs_sm_info {
unsigned int ipu_policy; /* in-place-update policy */
unsigned int min_ipu_util; /* in-place-update threshold */
unsigned int min_fsync_blocks; /* threshold for fsync */
+ unsigned int min_hot_blocks; /* threshold for hot block allocation */

/* for flush command control */
struct flush_cmd_control *fcc_info;
@@ -1717,6 +1718,7 @@ enum {
FI_DO_DEFRAG, /* indicate defragment is running */
FI_DIRTY_FILE, /* indicate regular/symlink has dirty pages */
FI_NO_PREALLOC, /* indicate skipped preallocated blocks */
+ FI_HOT_DATA, /* indicate file is hot */
};

static inline void __mark_inode_dirty_flag(struct inode *inode,
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index b5b2a4745328..bff3f3bc7827 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1841,18 +1841,16 @@ static int __get_segment_type_6(struct page *page, enum page_type p_type)
if (p_type == DATA) {
struct inode *inode = page->mapping->host;

- if (S_ISDIR(inode->i_mode))
- return CURSEG_HOT_DATA;
- else if (is_cold_data(page) || file_is_cold(inode))
+ if (is_cold_data(page) || file_is_cold(inode))
return CURSEG_COLD_DATA;
- else
- return CURSEG_WARM_DATA;
+ if (is_inode_flag_set(inode, FI_HOT_DATA))
+ return CURSEG_HOT_DATA;
+ return CURSEG_WARM_DATA;
} else {
if (IS_DNODE(page))
return is_cold_node(page) ? CURSEG_WARM_NODE :
CURSEG_HOT_NODE;
- else
- return CURSEG_COLD_NODE;
+ return CURSEG_COLD_NODE;
}
}

@@ -2959,6 +2957,7 @@ int build_segment_manager(struct f2fs_sb_info *sbi)
sm_info->ipu_policy = 1 << F2FS_IPU_FSYNC;
sm_info->min_ipu_util = DEF_MIN_IPU_UTIL;
sm_info->min_fsync_blocks = DEF_MIN_FSYNC_BLOCKS;
+ sm_info->min_hot_blocks = DEF_MIN_HOT_BLOCKS;

sm_info->trim_sections = DEF_BATCHED_TRIM_SECTIONS;

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 31846b0fcb95..57e36c1ce7bd 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -540,6 +540,7 @@ static inline int utilization(struct f2fs_sb_info *sbi)
*/
#define DEF_MIN_IPU_UTIL 70
#define DEF_MIN_FSYNC_BLOCKS 8
+#define DEF_MIN_HOT_BLOCKS 16

enum {
F2FS_IPU_FORCE,
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index b4c5c6298698..2d78f3c76d18 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -296,6 +296,7 @@ F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_fsync_blocks, min_fsync_blocks);
+F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_hot_blocks, min_hot_blocks);
F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, ram_thresh, ram_thresh);
F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, ra_nid_pages, ra_nid_pages);
F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, dirty_nats_ratio, dirty_nats_ratio);
@@ -321,6 +322,7 @@ static struct attribute *f2fs_attrs[] = {
ATTR_LIST(ipu_policy),
ATTR_LIST(min_ipu_util),
ATTR_LIST(min_fsync_blocks),
+ ATTR_LIST(min_hot_blocks),
ATTR_LIST(max_victim_search),
ATTR_LIST(dir_level),
ATTR_LIST(ram_thresh),