From: Andrew Morton 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 Cc: OGAWA Hirofumi Cc: Kumar Gala Cc: Pete Zaitcev Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- 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/