[Patch 5/9] Swapin delays

[Shailabh Nagar]

delayacct-swapin.patch

Account separately for block I/O delays 
incurred as a result of swapin page faults since
these are a result of insufficient rss limit.

Signed-off-by: Shailabh Nagar <nagar@xxxxxxxxxxxxxx>

 include/linux/sched.h |    5 ++++-
 kernel/delayacct.c    |   17 ++++++++++++-----
 mm/memory.c           |    4 ++++
 3 files changed, 20 insertions(+), 6 deletions(-)

Index: linux-2.6.16-rc5/include/linux/sched.h
===================================================================
--- linux-2.6.16-rc5.orig/include/linux/sched.h	2006-03-11 07:41:38.000000000 -0500
+++ linux-2.6.16-rc5/include/linux/sched.h	2006-03-11 07:41:39.000000000 -0500
@@ -550,9 +550,11 @@ struct task_delay_info {
 	 * u32 XXX_count;
 	 */
 
-	struct timespec blkio_start, blkio_end;
+	struct timespec blkio_start, blkio_end;	/* Shared by blkio, swapin */
 	u64 blkio_delay;	/* wait for sync block io completion */
+	u64 swapin_delay;	/* wait for sync block io completion */
 	u32 blkio_count;
+	u32 swapin_count;
 };
 #endif
 
@@ -949,6 +951,7 @@ static inline void put_task_struct(struc
 #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 */
+#define PF_SWAPIN	0x02000000	/* I am doing a swap in */
 
 /*
  * Only the _current_ task can read/write to tsk->flags, but other
Index: linux-2.6.16-rc5/kernel/delayacct.c
===================================================================
--- linux-2.6.16-rc5.orig/kernel/delayacct.c	2006-03-11 07:41:38.000000000 -0500
+++ linux-2.6.16-rc5/kernel/delayacct.c	2006-03-11 07:41:39.000000000 -0500
@@ -98,9 +98,16 @@ void __delayacct_blkio_start(void)
 
 void __delayacct_blkio_end(void)
 {
-	if (current->delays)
-		delayacct_end(&current->delays->blkio_start,
-				&current->delays->blkio_end,
-				&current->delays->blkio_delay,
-				&current->delays->blkio_count);
+	if (current->delays) {
+		if (current->flags & PF_SWAPIN)	/* Swapping a page in */
+			delayacct_end(&current->delays->blkio_start,
+				      &current->delays->blkio_end,
+				      &current->delays->swapin_delay,
+				      &current->delays->swapin_count);
+		else	/* Other block I/O */
+			delayacct_end(&current->delays->blkio_start,
+				      &current->delays->blkio_end,
+				      &current->delays->blkio_delay,
+				      &current->delays->blkio_count);
+	}
 }
Index: linux-2.6.16-rc5/mm/memory.c
===================================================================
--- linux-2.6.16-rc5.orig/mm/memory.c	2006-03-11 07:41:32.000000000 -0500
+++ linux-2.6.16-rc5/mm/memory.c	2006-03-11 07:41:39.000000000 -0500
@@ -1882,6 +1882,7 @@ static int do_swap_page(struct mm_struct
 
 	entry = pte_to_swp_entry(orig_pte);
 again:
+	current->flags |= PF_SWAPIN;
 	page = lookup_swap_cache(entry);
 	if (!page) {
  		swapin_readahead(entry, address, vma);
@@ -1894,6 +1895,7 @@ again:
 			page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
 			if (likely(pte_same(*page_table, orig_pte)))
 				ret = VM_FAULT_OOM;
+			current->flags &= ~PF_SWAPOFF;
 			goto unlock;
 		}
 
@@ -1905,6 +1907,8 @@ again:
 
 	mark_page_accessed(page);
 	lock_page(page);
+	current->flags &= ~PF_SWAPOFF;
+
 	if (!PageSwapCache(page)) {
 		/* Page migration has occured */
 		unlock_page(page);


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