Only do the congestion wait when we actually encountered congestion.
Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]>
---
include/linux/swap.h | 1 +
mm/page_io.c | 9 +++++++++
mm/vmscan.c | 25 ++++++++++++++++++++-----
3 files changed, 30 insertions(+), 5 deletions(-)
Index: linux-2.6-mm/mm/vmscan.c
===================================================================
--- linux-2.6-mm.orig/mm/vmscan.c 2007-04-05 16:29:49.000000000 +0200
+++ linux-2.6-mm/mm/vmscan.c 2007-04-05 16:35:36.000000000 +0200
@@ -70,6 +70,8 @@ struct scan_control {
int all_unreclaimable;
int order;
+
+ int encountered_congestion;
};
/*
@@ -315,7 +317,8 @@ typedef enum {
* pageout is called by shrink_page_list() for each dirty page.
* Calls ->writepage().
*/
-static pageout_t pageout(struct page *page, struct address_space *mapping)
+static pageout_t pageout(struct page *page, struct address_space *mapping,
+ struct scan_control *sc)
{
/*
* If the page is dirty, only perform writeback if that write
@@ -357,6 +360,7 @@ static pageout_t pageout(struct page *pa
if (clear_page_dirty_for_io(page)) {
int res;
+ struct backing_dev_info *bdi;
struct writeback_control wbc = {
.sync_mode = WB_SYNC_NONE,
.nr_to_write = SWAP_CLUSTER_MAX,
@@ -366,6 +370,14 @@ static pageout_t pageout(struct page *pa
.for_reclaim = 1,
};
+ if (mapping == &swapper_space)
+ bdi = swap_bdi(page);
+ else
+ bdi = mapping->backing_dev_info;
+
+ if (bdi_congested(bdi, WRITE))
+ sc->encountered_congestion = 1;
+
SetPageReclaim(page);
res = mapping->a_ops->writepage(page, &wbc);
if (res < 0)
@@ -533,7 +545,7 @@ static unsigned long shrink_page_list(st
goto keep_locked;
/* Page is dirty, try to write it out here */
- switch(pageout(page, mapping)) {
+ switch(pageout(page, mapping, sc)) {
case PAGE_KEEP:
goto keep_locked;
case PAGE_ACTIVATE:
@@ -1141,6 +1153,7 @@ unsigned long try_to_free_pages(struct z
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
sc.nr_scanned = 0;
+ sc.encountered_congestion = 0;
if (!priority)
disable_swap_token();
nr_reclaimed += shrink_zones(priority, zones, &sc);
@@ -1169,7 +1182,7 @@ unsigned long try_to_free_pages(struct z
}
/* Take a nap, wait for some writeback to complete */
- if (sc.nr_scanned && priority < DEF_PRIORITY - 2)
+ if (sc.encountered_congestion)
congestion_wait(WRITE, HZ/10);
}
/* top priority shrink_caches still had more to do? don't OOM, then */
@@ -1250,6 +1263,7 @@ loop_again:
int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */
unsigned long lru_pages = 0;
+ sc.encountered_congestion = 0;
/* The swap token gets in the way of swapout... */
if (!priority)
disable_swap_token();
@@ -1337,7 +1351,7 @@ loop_again:
* OK, kswapd is getting into trouble. Take a nap, then take
* another pass across the zones.
*/
- if (total_scanned && priority < DEF_PRIORITY - 2)
+ if (sc.encountered_congestion)
congestion_wait(WRITE, HZ/10);
/*
@@ -1580,6 +1594,7 @@ unsigned long shrink_all_memory(unsigned
unsigned long nr_to_scan = nr_pages - ret;
sc.nr_scanned = 0;
+ sc.encountered_congestion = 0;
ret += shrink_all_zones(nr_to_scan, prio, pass, &sc);
if (ret >= nr_pages)
goto out;
@@ -1591,7 +1606,7 @@ unsigned long shrink_all_memory(unsigned
if (ret >= nr_pages)
goto out;
- if (sc.nr_scanned && prio < DEF_PRIORITY - 2)
+ if (sc.encountered_congestion)
congestion_wait(WRITE, HZ / 10);
}
}
Index: linux-2.6-mm/include/linux/swap.h
===================================================================
--- linux-2.6-mm.orig/include/linux/swap.h 2007-04-05 16:24:02.000000000
+0200
+++ linux-2.6-mm/include/linux/swap.h 2007-04-05 16:35:36.000000000 +0200
@@ -220,6 +220,7 @@ extern void swap_unplug_io_fn(struct bac
#ifdef CONFIG_SWAP
/* linux/mm/page_io.c */
+extern struct backing_dev_info *swap_bdi(struct page *);
extern int swap_readpage(struct file *, struct page *);
extern int swap_writepage(struct page *page, struct writeback_control *wbc);
extern int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int
err);
Index: linux-2.6-mm/mm/page_io.c
===================================================================
--- linux-2.6-mm.orig/mm/page_io.c 2007-04-05 16:24:02.000000000 +0200
+++ linux-2.6-mm/mm/page_io.c 2007-04-05 16:36:26.000000000 +0200
@@ -19,6 +19,15 @@
#include <linux/writeback.h>
#include <asm/pgtable.h>
+struct backing_dev_info *swap_bdi(struct page *page)
+{
+ struct swap_info_struct *sis;
+ swp_entry_t entry = { .val = page_private(page), };
+
+ sis = get_swap_info_struct(swp_type(entry));
+ return blk_get_backing_dev_info(sis->bdev);
+}
+
static struct bio *get_swap_bio(gfp_t gfp_flags, pgoff_t index,
struct page *page, bio_end_io_t end_io)
{
--
-
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