f2fs: merge meta writes as many possible

This patch tries to merge IOs as many as possible when background flusher
conducts flushing the dirty meta pages.

[Before]

...
2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 124320, size = 4096
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 124560, size = 32768
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 95720, size = 987136
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 123928, size = 4096
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 123944, size = 8192
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 123968, size = 45056
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 124064, size = 4096
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 97648, size = 1007616
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 123776, size = 8192
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 123800, size = 32768
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 124624, size = 4096
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 99616, size = 921600
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 123608, size = 4096
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 123624, size = 77824
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 123792, size = 4096
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 123864, size = 32768
...

[After]

...
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 92168, size = 892928
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 93912, size = 753664
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 95384, size = 716800
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 96784, size = 712704
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 104160, size = 364544
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 104872, size = 356352
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 105568, size = 278528
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 106112, size = 319488
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 106736, size = 258048
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 107240, size = 270336
f2fs_submit_write_bio: dev = (8,18), WRITE_SYNC(MP), META, sector = 107768, size = 180224
...

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 0569097dbd7ab29d4f43b6311d799cf4553a3f73..0a9ec4228342c90fe4882365bd8c87e3fe1ef67b 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -257,7 +257,7 @@ long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
                                                long nr_to_write)
 {
        struct address_space *mapping = META_MAPPING(sbi);
-       pgoff_t index = 0, end = LONG_MAX;
+       pgoff_t index = 0, end = LONG_MAX, prev = LONG_MAX;
        struct pagevec pvec;
        long nwritten = 0;
        struct writeback_control wbc = {
@@ -277,6 +277,13 @@ long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
                for (i = 0; i < nr_pages; i++) {
                        struct page *page = pvec.pages[i];
 
+                       if (prev == LONG_MAX)
+                               prev = page->index - 1;
+                       if (nr_to_write != LONG_MAX && page->index != prev + 1) {
+                               pagevec_release(&pvec);
+                               goto stop;
+                       }
+
                        lock_page(page);
 
                        if (unlikely(page->mapping != mapping)) {
@@ -297,13 +304,14 @@ continue_unlock:
                                break;
                        }
                        nwritten++;
+                       prev = page->index;
                        if (unlikely(nwritten >= nr_to_write))
                                break;
                }
                pagevec_release(&pvec);
                cond_resched();
        }
-
+stop:
        if (nwritten)
                f2fs_submit_merged_bio(sbi, type, WRITE);