Add PF_SWAPWRITE to control a processes permission to write to swap. - Use PF_SWAPWRITE in may_write_to_queue() instead of checking for kswapd and pdflush - Set PF_SWAPWRITE flag for kswapd and pdflush Signed-off-by: Christoph Lameter Index: linux-2.6.14-rc5-mm1/include/linux/sched.h =================================================================== --- linux-2.6.14-rc5-mm1.orig/include/linux/sched.h 2005-10-24 10:27:29.000000000 -0700 +++ linux-2.6.14-rc5-mm1/include/linux/sched.h 2005-10-31 13:30:48.000000000 -0800 @@ -914,6 +914,7 @@ do { if (atomic_dec_and_test(&(tsk)->usa #define PF_SYNCWRITE 0x00200000 /* I am doing a sync write */ #define PF_BORROWED_MM 0x00400000 /* I am a kthread doing use_mm */ #define PF_RANDOMIZE 0x00800000 /* randomize virtual address space */ +#define PF_SWAPWRITE 0x01000000 /* the process is allowed to write to swap */ /* * Only the _current_ task can read/write to tsk->flags, but other Index: linux-2.6.14-rc5-mm1/mm/vmscan.c =================================================================== --- linux-2.6.14-rc5-mm1.orig/mm/vmscan.c 2005-10-31 13:21:57.000000000 -0800 +++ linux-2.6.14-rc5-mm1/mm/vmscan.c 2005-10-31 13:30:48.000000000 -0800 @@ -263,9 +263,7 @@ static inline int is_page_cache_freeable static int may_write_to_queue(struct backing_dev_info *bdi) { - if (current_is_kswapd()) - return 1; - if (current_is_pdflush()) /* This is unlikely, but why not... */ + if (current->flags & PF_SWAPWRITE) return 1; if (!bdi_write_congested(bdi)) return 1; @@ -1289,7 +1287,7 @@ static int kswapd(void *p) * us from recursively trying to free more memory as we're * trying to free the first piece of memory in the first place). */ - tsk->flags |= PF_MEMALLOC|PF_KSWAPD; + tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; order = 0; for ( ; ; ) { Index: linux-2.6.14-rc5-mm1/mm/pdflush.c =================================================================== --- linux-2.6.14-rc5-mm1.orig/mm/pdflush.c 2005-10-24 10:27:21.000000000 -0700 +++ linux-2.6.14-rc5-mm1/mm/pdflush.c 2005-10-31 13:30:48.000000000 -0800 @@ -90,7 +90,7 @@ struct pdflush_work { static int __pdflush(struct pdflush_work *my_work) { - current->flags |= PF_FLUSHER; + current->flags |= PF_FLUSHER | PF_SWAPWRITE; my_work->fn = NULL; my_work->who = current; INIT_LIST_HEAD(&my_work->list);