From fc3ba692a4d19019387c5acaea63131f9eab05dd Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Wed, 30 Apr 2008 00:54:38 -0700 Subject: mm: Add NR_WRITEBACK_TEMP counter Fuse will use temporary buffers to write back dirty data from memory mappings (normal writes are done synchronously). This is needed, because there cannot be any guarantee about the time in which a write will complete. By using temporary buffers, from the MM's point if view the page is written back immediately. If the writeout was due to memory pressure, this effectively migrates data from a full zone to a less full zone. This patch adds a new counter (NR_WRITEBACK_TEMP) for the number of pages used as temporary buffers. [Lee.Schermerhorn@hp.com: add vmstat_text for NR_WRITEBACK_TEMP] Signed-off-by: Miklos Szeredi Cc: Christoph Lameter Signed-off-by: Lee Schermerhorn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page-writeback.c | 3 ++- mm/vmstat.c | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/page-writeback.c b/mm/page-writeback.c index c90a1e8e479f..789b6adbef37 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -211,7 +211,8 @@ clip_bdi_dirty_limit(struct backing_dev_info *bdi, long dirty, long *pbdi_dirty) avail_dirty = dirty - (global_page_state(NR_FILE_DIRTY) + global_page_state(NR_WRITEBACK) + - global_page_state(NR_UNSTABLE_NFS)); + global_page_state(NR_UNSTABLE_NFS) + + global_page_state(NR_WRITEBACK_TEMP)); if (avail_dirty < 0) avail_dirty = 0; diff --git a/mm/vmstat.c b/mm/vmstat.c index 280a7ed549f2..1a32130b958c 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -612,6 +612,7 @@ static const char * const vmstat_text[] = { "nr_unstable", "nr_bounce", "nr_vmscan_write", + "nr_writeback_temp", #ifdef CONFIG_NUMA "numa_hit", -- cgit v1.2.3