[PATCH 19/35] writeback: make nr_to_write a per-file limit

Wu Fengguang
2010-12-13T15:09:07Z

[-- Attachment #1: writeback-single-file-limit.patch --]
[-- Type: text/plain, Size: 1883 bytes --]

This ensures full 4MB (or larger) writeback size for large dirty files.

CC: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
fs/fs-writeback.c | 11 +++++++++++
include/linux/writeback.h | 1 +
2 files changed, 12 insertions(+)

--- linux-next.orig/fs/fs-writeback.c 2010-12-13 21:46:14.000000000 +0800
+++ linux-next/fs/fs-writeback.c 2010-12-13 21:46:17.000000000 +0800
@@ -330,6 +330,8 @@ static int
writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
{
struct address_space *mapping = inode->i_mapping;
+ long per_file_limit = wbc->per_file_limit;
+ long uninitialized_var(nr_to_write);
unsigned dirty;
int ret;

@@ -365,8 +367,16 @@ writeback_single_inode(struct inode *ino
inode->i_state &= ~I_DIRTY_PAGES;
spin_unlock(&inode_lock);

+ if (per_file_limit) {
+ nr_to_write = wbc->nr_to_write;
+ wbc->nr_to_write = per_file_limit;
+ }
+
ret = do_writepages(mapping, wbc);

+ if (per_file_limit)
+ wbc->nr_to_write += nr_to_write - per_file_limit;
+
/*
* Make sure to wait on the data before writing out the metadata.
* This is important for filesystems that modify metadata on data
@@ -696,6 +706,7 @@ static long wb_writeback(struct bdi_writ

wbc.more_io = 0;
wbc.nr_to_write = write_chunk;
+ wbc.per_file_limit = write_chunk;
wbc.pages_skipped = 0;

trace_wbc_writeback_start(&wbc, wb->bdi);
--- linux-next.orig/include/linux/writeback.h 2010-12-13 21:46:14.000000000 +0800
+++ linux-next/include/linux/writeback.h 2010-12-13 21:46:17.000000000 +0800
@@ -43,6 +43,7 @@ struct writeback_control {
extra jobs and livelock */
long nr_to_write; /* Write this many pages, and decrement
this for each page written */
+ long per_file_limit; /* Write this many pages for one file */
long pages_skipped; /* Pages which were not written */

/*