Commit 930d9152 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds

[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: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 21eac81f
......@@ -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
......
......@@ -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);
......
......@@ -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 ( ; ; ) {
......
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