lkml.org 
[lkml]   [2007]   [Mar]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch 095/101] throttle_vm_writeout(): dont loop on GFP_NOFS and GFP_NOIO allocations

From: Andrew Morton <akpm@linux-foundation.org>

throttle_vm_writeout() is designed to wait for the dirty levels to subside.
But if the caller holds IO or FS locks, we might be holding up that writeout.

So change it to take a single nap to give other devices a chance to clean some
memory, then return.

Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
include/linux/writeback.h | 2 +-
mm/page-writeback.c | 13 +++++++++++--
mm/vmscan.c | 2 +-
3 files changed, 13 insertions(+), 4 deletions(-)
--- linux-2.6.20.1.orig/include/linux/writeback.h
+++ linux-2.6.20.1/include/linux/writeback.h
@@ -84,7 +84,7 @@ static inline void wait_on_inode(struct
int wakeup_pdflush(long nr_pages);
void laptop_io_completion(void);
void laptop_sync_completion(void);
-void throttle_vm_writeout(void);
+void throttle_vm_writeout(gfp_t gfp_mask);

/* These are exported to sysctl. */
extern int dirty_background_ratio;
--- linux-2.6.20.1.orig/mm/page-writeback.c
+++ linux-2.6.20.1/mm/page-writeback.c
@@ -296,11 +296,21 @@ void balance_dirty_pages_ratelimited_nr(
}
EXPORT_SYMBOL(balance_dirty_pages_ratelimited_nr);

-void throttle_vm_writeout(void)
+void throttle_vm_writeout(gfp_t gfp_mask)
{
long background_thresh;
long dirty_thresh;

+ if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {
+ /*
+ * The caller might hold locks which can prevent IO completion
+ * or progress in the filesystem. So we cannot just sit here
+ * waiting for IO to complete.
+ */
+ congestion_wait(WRITE, HZ/10);
+ return;
+ }
+
for ( ; ; ) {
get_dirty_limits(&background_thresh, &dirty_thresh, NULL);

@@ -317,7 +327,6 @@ void throttle_vm_writeout(void)
}
}

-
/*
* writeback at least _min_pages, and keep writing until the amount of dirty
* memory is less than the background threshold, or until we're all clean.
--- linux-2.6.20.1.orig/mm/vmscan.c
+++ linux-2.6.20.1/mm/vmscan.c
@@ -949,7 +949,7 @@ static unsigned long shrink_zone(int pri
}
}

- throttle_vm_writeout();
+ throttle_vm_writeout(sc->gfp_mask);

atomic_dec(&zone->reclaim_in_progress);
return nr_reclaimed;
--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-03-07 18:23    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site