f2fs: introduce nr_pages_to_write for segment alignment

This patch introduces nr_pages_to_write to align page writes to the segment
or other operational unit size, which can be tuned according to the system
environment.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index aef32f36e2f3f7ce12c5578b65cd6e34ca202416..2a00c94726fb9bf3d6ff21175507852ace69163b 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -187,18 +187,19 @@ static int f2fs_write_meta_pages(struct address_space *mapping,
                                struct writeback_control *wbc)
 {
        struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
-       int nrpages = nr_pages_to_skip(sbi, META);
-       long written;
+       long diff, written;
 
        /* collect a number of dirty meta pages and write together */
-       if (wbc->for_kupdate || get_pages(sbi, F2FS_DIRTY_META) < nrpages)
+       if (wbc->for_kupdate ||
+               get_pages(sbi, F2FS_DIRTY_META) < nr_pages_to_skip(sbi, META))
                goto skip_write;
 
        /* if mounting is failed, skip writing node pages */
        mutex_lock(&sbi->cp_mutex);
-       written = sync_meta_pages(sbi, META, nrpages);
+       diff = nr_pages_to_write(sbi, META, wbc);
+       written = sync_meta_pages(sbi, META, wbc->nr_to_write);
        mutex_unlock(&sbi->cp_mutex);
-       wbc->nr_to_write -= written;
+       wbc->nr_to_write = max((long)0, wbc->nr_to_write - written - diff);
        return 0;
 
 skip_write:

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 3bc380942068d45a49a97b24079b47edbc20ad27..b0c923aef229bc69ddc43c01ef1f894435a550f6 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -844,8 +844,6 @@ redirty_out:
        return AOP_WRITEPAGE_ACTIVATE;
 }
 
-#define MAX_DESIRED_PAGES_WP   4096
-
 static int __f2fs_writepage(struct page *page, struct writeback_control *wbc,
                        void *data)
 {
@@ -862,7 +860,7 @@ static int f2fs_write_data_pages(struct address_space *mapping,
        struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
        bool locked = false;
        int ret;
-       long excess_nrtw = 0, desired_nrtw;
+       long diff;
 
        /* deal with chardevs and other special file */
        if (!mapping->a_ops->writepage)
@@ -872,11 +870,7 @@ static int f2fs_write_data_pages(struct address_space *mapping,
                        get_dirty_dents(inode) < nr_pages_to_skip(sbi, DATA))
                goto skip_write;
 
-       if (wbc->nr_to_write < MAX_DESIRED_PAGES_WP) {
-               desired_nrtw = MAX_DESIRED_PAGES_WP;
-               excess_nrtw = desired_nrtw - wbc->nr_to_write;
-               wbc->nr_to_write = desired_nrtw;
-       }
+       diff = nr_pages_to_write(sbi, DATA, wbc);
 
        if (!S_ISDIR(inode->i_mode)) {
                mutex_lock(&sbi->writepages);
@@ -890,7 +884,7 @@ static int f2fs_write_data_pages(struct address_space *mapping,
 
        remove_dirty_dir_inode(inode);
 
-       wbc->nr_to_write -= excess_nrtw;
+       wbc->nr_to_write = max((long)0, wbc->nr_to_write - diff);
        return ret;
 
 skip_write:

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 7cc146bcbfed1df06fc6c481e4cdecdb5a4f401e..5e9c38e846a56017c2d1141da04de6db488ff523 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1202,7 +1202,7 @@ static int f2fs_write_node_pages(struct address_space *mapping,
                            struct writeback_control *wbc)
 {
        struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
-       long nr_to_write = wbc->nr_to_write;
+       long diff;
 
        /* balancing f2fs's metadata in background */
        f2fs_balance_fs_bg(sbi);
@@ -1211,12 +1211,10 @@ static int f2fs_write_node_pages(struct address_space *mapping,
        if (get_pages(sbi, F2FS_DIRTY_NODES) < nr_pages_to_skip(sbi, NODE))
                goto skip_write;
 
-       /* if mounting is failed, skip writing node pages */
-       wbc->nr_to_write = 3 * max_hw_blocks(sbi);
+       diff = nr_pages_to_write(sbi, NODE, wbc);
        wbc->sync_mode = WB_SYNC_NONE;
        sync_node_pages(sbi, 0, wbc);
-       wbc->nr_to_write = nr_to_write - (3 * max_hw_blocks(sbi) -
-                                               wbc->nr_to_write);
+       wbc->nr_to_write = max((long)0, wbc->nr_to_write - diff);
        return 0;
 
 skip_write:

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index bbd976100d142f6053c9ef346022e75e2084ec01..9fc46ee27bb8ce65ec94662bf1b3ce4829936c93 100644 (file)
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -683,3 +683,27 @@ static inline int nr_pages_to_skip(struct f2fs_sb_info *sbi, int type)
        else
                return 0;
 }
+
+/*
+ * When writing pages, it'd better align nr_to_write for segment size.
+ */
+static inline long nr_pages_to_write(struct f2fs_sb_info *sbi, int type,
+                                       struct writeback_control *wbc)
+{
+       long nr_to_write, desired;
+
+       if (wbc->sync_mode != WB_SYNC_NONE)
+               return 0;
+
+       nr_to_write = wbc->nr_to_write;
+
+       if (type == DATA)
+               desired = 4096;
+       else if (type == NODE)
+               desired = 3 * max_hw_blocks(sbi);
+       else
+               desired = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
+
+       wbc->nr_to_write = desired;
+       return desired - nr_to_write;
+}