f2fs: split journal cache from curseg cache
In curseg cache, f2fs caches two different parts:
- datas of current summay block, i.e. summary entries, footer info.
- journal info, i.e. sparse nat/sit entries or io stat info.
With this approach, 1) it may cause higher lock contention when we access
or update both of the parts of cache since we use the same mutex lock
curseg_mutex to protect the cache. 2) current summary block with last
journal info will be writebacked into device as a normal summary block
when flushing, however, we treat journal info as valid one only in current
summary, so most normal summary blocks contain junk journal data, it wastes
remaining space of summary block.
So, in order to fix above issues, we split curseg cache into two parts:
a) current summary block, protected by original mutex lock curseg_mutex
b) journal cache, protected by newly introduced r/w semaphore journal_rwsem
When loading curseg cache during ->mount, we store summary info and
journal info into different caches; When doing checkpoint, we combine
datas of two cache into current summary block for persisting.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index eb7979d..5d0e6e6 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -922,6 +922,31 @@
update_meta_page(sbi, (void *)sum_blk, blk_addr);
}
+static void write_current_sum_page(struct f2fs_sb_info *sbi,
+ int type, block_t blk_addr)
+{
+ struct curseg_info *curseg = CURSEG_I(sbi, type);
+ struct page *page = grab_meta_page(sbi, blk_addr);
+ struct f2fs_summary_block *src = curseg->sum_blk;
+ struct f2fs_summary_block *dst;
+
+ dst = (struct f2fs_summary_block *)page_address(page);
+
+ mutex_lock(&curseg->curseg_mutex);
+
+ down_read(&curseg->journal_rwsem);
+ memcpy(&dst->journal, curseg->journal, SUM_JOURNAL_SIZE);
+ up_read(&curseg->journal_rwsem);
+
+ memcpy(dst->entries, src->entries, SUM_ENTRY_SIZE);
+ memcpy(&dst->footer, &src->footer, SUM_FOOTER_SIZE);
+
+ mutex_unlock(&curseg->curseg_mutex);
+
+ set_page_dirty(page);
+ f2fs_put_page(page, 1);
+}
+
static int is_next_segment_free(struct f2fs_sb_info *sbi, int type)
{
struct curseg_info *curseg = CURSEG_I(sbi, type);
@@ -1544,12 +1569,11 @@
/* Step 1: restore nat cache */
seg_i = CURSEG_I(sbi, CURSEG_HOT_DATA);
- memcpy(&seg_i->sum_blk->journal.n_nats, kaddr, SUM_JOURNAL_SIZE);
+ memcpy(seg_i->journal, kaddr, SUM_JOURNAL_SIZE);
/* Step 2: restore sit cache */
seg_i = CURSEG_I(sbi, CURSEG_COLD_DATA);
- memcpy(&seg_i->sum_blk->journal.n_sits, kaddr + SUM_JOURNAL_SIZE,
- SUM_JOURNAL_SIZE);
+ memcpy(seg_i->journal, kaddr + SUM_JOURNAL_SIZE, SUM_JOURNAL_SIZE);
offset = 2 * SUM_JOURNAL_SIZE;
/* Step 3: restore summary entries */
@@ -1645,7 +1669,14 @@
/* set uncompleted segment to curseg */
curseg = CURSEG_I(sbi, type);
mutex_lock(&curseg->curseg_mutex);
- memcpy(curseg->sum_blk, sum, PAGE_CACHE_SIZE);
+
+ /* update journal info */
+ down_write(&curseg->journal_rwsem);
+ memcpy(curseg->journal, &sum->journal, SUM_JOURNAL_SIZE);
+ up_write(&curseg->journal_rwsem);
+
+ memcpy(curseg->sum_blk->entries, sum->entries, SUM_ENTRY_SIZE);
+ memcpy(&curseg->sum_blk->footer, &sum->footer, SUM_FOOTER_SIZE);
curseg->next_segno = segno;
reset_curseg(sbi, type, 0);
curseg->alloc_type = ckpt->alloc_type[type];
@@ -1700,13 +1731,12 @@
/* Step 1: write nat cache */
seg_i = CURSEG_I(sbi, CURSEG_HOT_DATA);
- memcpy(kaddr, &seg_i->sum_blk->journal.n_nats, SUM_JOURNAL_SIZE);
+ memcpy(kaddr, seg_i->journal, SUM_JOURNAL_SIZE);
written_size += SUM_JOURNAL_SIZE;
/* Step 2: write sit cache */
seg_i = CURSEG_I(sbi, CURSEG_COLD_DATA);
- memcpy(kaddr + written_size, &seg_i->sum_blk->journal.n_sits,
- SUM_JOURNAL_SIZE);
+ memcpy(kaddr + written_size, seg_i->journal, SUM_JOURNAL_SIZE);
written_size += SUM_JOURNAL_SIZE;
/* Step 3: write summary entries */
@@ -1752,12 +1782,8 @@
else
end = type + NR_CURSEG_NODE_TYPE;
- for (i = type; i < end; i++) {
- struct curseg_info *sum = CURSEG_I(sbi, i);
- mutex_lock(&sum->curseg_mutex);
- write_sum_page(sbi, sum->sum_blk, blkaddr + (i - type));
- mutex_unlock(&sum->curseg_mutex);
- }
+ for (i = type; i < end; i++)
+ write_current_sum_page(sbi, i, blkaddr + (i - type));
}
void write_data_summaries(struct f2fs_sb_info *sbi, block_t start_blk)
@@ -1894,9 +1920,10 @@
static void remove_sits_in_journal(struct f2fs_sb_info *sbi)
{
struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_COLD_DATA);
- struct f2fs_journal *journal = &curseg->sum_blk->journal;
+ struct f2fs_journal *journal = curseg->journal;
int i;
+ down_write(&curseg->journal_rwsem);
for (i = 0; i < sits_in_cursum(journal); i++) {
unsigned int segno;
bool dirtied;
@@ -1908,6 +1935,7 @@
add_sit_entry(segno, &SM_I(sbi)->sit_entry_set);
}
update_sits_in_cursum(journal, -i);
+ up_write(&curseg->journal_rwsem);
}
/*
@@ -1919,13 +1947,12 @@
struct sit_info *sit_i = SIT_I(sbi);
unsigned long *bitmap = sit_i->dirty_sentries_bitmap;
struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_COLD_DATA);
- struct f2fs_journal *journal = &curseg->sum_blk->journal;
+ struct f2fs_journal *journal = curseg->journal;
struct sit_entry_set *ses, *tmp;
struct list_head *head = &SM_I(sbi)->sit_entry_set;
bool to_journal = true;
struct seg_entry *se;
- mutex_lock(&curseg->curseg_mutex);
mutex_lock(&sit_i->sentry_lock);
if (!sit_i->dirty_sentries)
@@ -1962,7 +1989,9 @@
!__has_cursum_space(journal, ses->entry_cnt, SIT_JOURNAL))
to_journal = false;
- if (!to_journal) {
+ if (to_journal) {
+ down_write(&curseg->journal_rwsem);
+ } else {
page = get_next_sit_page(sbi, start_segno);
raw_sit = page_address(page);
}
@@ -1998,7 +2027,9 @@
ses->entry_cnt--;
}
- if (!to_journal)
+ if (to_journal)
+ up_write(&curseg->journal_rwsem);
+ else
f2fs_put_page(page, 1);
f2fs_bug_on(sbi, ses->entry_cnt);
@@ -2013,7 +2044,6 @@
add_discard_addrs(sbi, cpc);
}
mutex_unlock(&sit_i->sentry_lock);
- mutex_unlock(&curseg->curseg_mutex);
set_prefree_as_free_segments(sbi);
}
@@ -2145,6 +2175,11 @@
array[i].sum_blk = kzalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
if (!array[i].sum_blk)
return -ENOMEM;
+ init_rwsem(&array[i].journal_rwsem);
+ array[i].journal = kzalloc(sizeof(struct f2fs_journal),
+ GFP_KERNEL);
+ if (!array[i].journal)
+ return -ENOMEM;
array[i].segno = NULL_SEGNO;
array[i].next_blkoff = 0;
}
@@ -2155,7 +2190,7 @@
{
struct sit_info *sit_i = SIT_I(sbi);
struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_COLD_DATA);
- struct f2fs_journal *journal = &curseg->sum_blk->journal;
+ struct f2fs_journal *journal = curseg->journal;
int sit_blk_cnt = SIT_BLK_CNT(sbi);
unsigned int i, start, end;
unsigned int readed, start_blk = 0;
@@ -2173,16 +2208,16 @@
struct f2fs_sit_entry sit;
struct page *page;
- mutex_lock(&curseg->curseg_mutex);
+ down_read(&curseg->journal_rwsem);
for (i = 0; i < sits_in_cursum(journal); i++) {
if (le32_to_cpu(segno_in_journal(journal, i))
== start) {
sit = sit_in_journal(journal, i);
- mutex_unlock(&curseg->curseg_mutex);
+ up_read(&curseg->journal_rwsem);
goto got_it;
}
}
- mutex_unlock(&curseg->curseg_mutex);
+ up_read(&curseg->journal_rwsem);
page = get_current_sit_page(sbi, start);
sit_blk = (struct f2fs_sit_block *)page_address(page);
@@ -2417,8 +2452,10 @@
if (!array)
return;
SM_I(sbi)->curseg_array = NULL;
- for (i = 0; i < NR_CURSEG_TYPE; i++)
+ for (i = 0; i < NR_CURSEG_TYPE; i++) {
kfree(array[i].sum_blk);
+ kfree(array[i].journal);
+ }
kfree(array);
}