From: Peter Zijlstra These patches aim to improve balance_dirty_pages() and directly address three issues: 1) inter device starvation 2) stacked device deadlocks 3) inter process starvation 1 and 2 are a direct result from removing the global dirty limit and using per device dirty limits. By giving each device its own dirty limit is will no longer starve another device, and the cyclic dependancy on the dirty limit is broken. In order to efficiently distribute the dirty limit across the independant devices a floating proportion is used, this will allocate a share of the total limit proportional to the device's recent activity. 3 is done by also scaling the dirty limit proportional to the current task's recent dirty rate. This patch: nfs: remove congestion_end(). It's redundant, clear_bdi_congested() already wakes the waiters. Signed-off-by: Peter Zijlstra Cc: Trond Myklebust Cc: "J. Bruce Fields" Signed-off-by: Andrew Morton --- fs/nfs/write.c | 4 +--- include/linux/backing-dev.h | 1 - mm/backing-dev.c | 13 ------------- 3 files changed, 1 insertion(+), 17 deletions(-) diff -puN fs/nfs/write.c~nfs-remove-congestion_end fs/nfs/write.c --- a/fs/nfs/write.c~nfs-remove-congestion_end +++ a/fs/nfs/write.c @@ -242,10 +242,8 @@ static void nfs_end_page_writeback(struc struct nfs_server *nfss = NFS_SERVER(inode); end_page_writeback(page); - if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) { + if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) clear_bdi_congested(&nfss->backing_dev_info, WRITE); - congestion_end(WRITE); - } } /* diff -puN include/linux/backing-dev.h~nfs-remove-congestion_end include/linux/backing-dev.h --- a/include/linux/backing-dev.h~nfs-remove-congestion_end +++ a/include/linux/backing-dev.h @@ -93,7 +93,6 @@ static inline int bdi_rw_congested(struc void clear_bdi_congested(struct backing_dev_info *bdi, int rw); void set_bdi_congested(struct backing_dev_info *bdi, int rw); long congestion_wait(int rw, long timeout); -void congestion_end(int rw); #define bdi_cap_writeback_dirty(bdi) \ (!((bdi)->capabilities & BDI_CAP_NO_WRITEBACK)) diff -puN mm/backing-dev.c~nfs-remove-congestion_end mm/backing-dev.c --- a/mm/backing-dev.c~nfs-remove-congestion_end +++ a/mm/backing-dev.c @@ -54,16 +54,3 @@ long congestion_wait(int rw, long timeou return ret; } EXPORT_SYMBOL(congestion_wait); - -/** - * congestion_end - wake up sleepers on a congested backing_dev_info - * @rw: READ or WRITE - */ -void congestion_end(int rw) -{ - wait_queue_head_t *wqh = &congestion_wqh[rw]; - - if (waitqueue_active(wqh)) - wake_up(wqh); -} -EXPORT_SYMBOL(congestion_end); _