From 930d915252edda7042c944ed3c30194a2f9fe163 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Sun, 8 Jan 2006 01:00:47 -0800 Subject: [PATCH] [PATCH] Swap Migration V5: PF_SWAPWRITE to allow writing to swap 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sched.h | 1 + mm/pdflush.c | 2 +- mm/vmscan.c | 6 ++---- 3 files changed, 4 insertions(+), 5 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 7da33619d5d0..a74662077d60 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -895,6 +895,7 @@ do { if (atomic_dec_and_test(&(tsk)->usage)) __put_task_struct(tsk); } while(0) #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 /* Allowed to write to swap */ /* * Only the _current_ task can read/write to tsk->flags, but other diff --git a/mm/pdflush.c b/mm/pdflush.c index 52822c98c489..c4b6d0afd736 100644 --- a/mm/pdflush.c +++ b/mm/pdflush.c @@ -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); diff --git a/mm/vmscan.c b/mm/vmscan.c index 261a56ee11b6..6c30a8c59795 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -268,9 +268,7 @@ static inline int is_page_cache_freeable(struct page *page) 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; @@ -1299,7 +1297,7 @@ 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 ( ; ; ) { -- 2.30.2