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authorShailabh Nagar <nagar@watson.ibm.com>2006-07-14 00:24:37 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-14 21:53:56 -0700
commit0ff922452df86f3e9a2c6f705c4588ec62d096a7 (patch)
treeac84041bfb63f12d0e2db733c46b2cd2438b4882
parentca74e92b4698276b6696f15a801759f50944f387 (diff)
downloadlinux-2.6.34-ux500-0ff922452df86f3e9a2c6f705c4588ec62d096a7.tar.gz
[PATCH] per-task-delay-accounting: sync block I/O and swapin delay collection
Unlike earlier iterations of the delay accounting patches, now delays are only collected for the actual I/O waits rather than try and cover the delays seen in I/O submission paths. Account separately for block I/O delays incurred as a result of swapin page faults whose frequency can be affected by the task/process' rss limit. Hence swapin delays can act as feedback for rss limit changes independent of I/O priority changes. Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Balbir Singh <balbir@in.ibm.com> Cc: Jes Sorensen <jes@sgi.com> Cc: Peter Chubb <peterc@gelato.unsw.edu.au> Cc: Erich Focht <efocht@ess.nec.de> Cc: Levent Serinol <lserinol@gmail.com> Cc: Jay Lan <jlan@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/linux/delayacct.h25
-rw-r--r--include/linux/sched.h13
-rw-r--r--kernel/delayacct.c19
-rw-r--r--kernel/sched.c5
-rw-r--r--mm/memory.c4
5 files changed, 66 insertions, 0 deletions
diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h
index 9572cfa1f12..0ecbf9aad8e 100644
--- a/include/linux/delayacct.h
+++ b/include/linux/delayacct.h
@@ -19,6 +19,13 @@
#include <linux/sched.h>
+/*
+ * Per-task flags relevant to delay accounting
+ * maintained privately to avoid exhausting similar flags in sched.h:PF_*
+ * Used to set current->delays->flags
+ */
+#define DELAYACCT_PF_SWAPIN 0x00000001 /* I am doing a swapin */
+
#ifdef CONFIG_TASK_DELAY_ACCT
extern int delayacct_on; /* Delay accounting turned on/off */
@@ -26,6 +33,8 @@ extern kmem_cache_t *delayacct_cache;
extern void delayacct_init(void);
extern void __delayacct_tsk_init(struct task_struct *);
extern void __delayacct_tsk_exit(struct task_struct *);
+extern void __delayacct_blkio_start(void);
+extern void __delayacct_blkio_end(void);
static inline void delayacct_set_flag(int flag)
{
@@ -53,6 +62,18 @@ static inline void delayacct_tsk_exit(struct task_struct *tsk)
__delayacct_tsk_exit(tsk);
}
+static inline void delayacct_blkio_start(void)
+{
+ if (current->delays)
+ __delayacct_blkio_start();
+}
+
+static inline void delayacct_blkio_end(void)
+{
+ if (current->delays)
+ __delayacct_blkio_end();
+}
+
#else
static inline void delayacct_set_flag(int flag)
{}
@@ -64,6 +85,10 @@ static inline void delayacct_tsk_init(struct task_struct *tsk)
{}
static inline void delayacct_tsk_exit(struct task_struct *tsk)
{}
+static inline void delayacct_blkio_start(void)
+{}
+static inline void delayacct_blkio_end(void)
+{}
#endif /* CONFIG_TASK_DELAY_ACCT */
#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7a54e62763c..2f43f1fb7de 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -566,6 +566,19 @@ struct task_delay_info {
* Atomicity of updates to XXX_delay, XXX_count protected by
* single lock above (split into XXX_lock if contention is an issue).
*/
+
+ /*
+ * XXX_count is incremented on every XXX operation, the delay
+ * associated with the operation is added to XXX_delay.
+ * XXX_delay contains the accumulated delay time in nanoseconds.
+ */
+ struct timespec blkio_start, blkio_end; /* Shared by blkio, swapin */
+ u64 blkio_delay; /* wait for sync block io completion */
+ u64 swapin_delay; /* wait for swapin block io completion */
+ u32 blkio_count; /* total count of the number of sync block */
+ /* io operations performed */
+ u32 swapin_count; /* total count of the number of swapin block */
+ /* io operations performed */
};
#endif
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index fbf7f228495..3546b0800f9 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -85,3 +85,22 @@ static void delayacct_end(struct timespec *start, struct timespec *end,
spin_unlock(&current->delays->lock);
}
+void __delayacct_blkio_start(void)
+{
+ delayacct_start(&current->delays->blkio_start);
+}
+
+void __delayacct_blkio_end(void)
+{
+ if (current->delays->flags & DELAYACCT_PF_SWAPIN)
+ /* Swapin block I/O */
+ 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);
+}
diff --git a/kernel/sched.c b/kernel/sched.c
index e9a0b61f12a..9d42cbfc4f8 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -51,6 +51,7 @@
#include <linux/times.h>
#include <linux/acct.h>
#include <linux/kprobes.h>
+#include <linux/delayacct.h>
#include <asm/tlb.h>
#include <asm/unistd.h>
@@ -4534,9 +4535,11 @@ void __sched io_schedule(void)
{
struct rq *rq = &__raw_get_cpu_var(runqueues);
+ delayacct_blkio_start();
atomic_inc(&rq->nr_iowait);
schedule();
atomic_dec(&rq->nr_iowait);
+ delayacct_blkio_end();
}
EXPORT_SYMBOL(io_schedule);
@@ -4545,9 +4548,11 @@ long __sched io_schedule_timeout(long timeout)
struct rq *rq = &__raw_get_cpu_var(runqueues);
long ret;
+ delayacct_blkio_start();
atomic_inc(&rq->nr_iowait);
ret = schedule_timeout(timeout);
atomic_dec(&rq->nr_iowait);
+ delayacct_blkio_end();
return ret;
}
diff --git a/mm/memory.c b/mm/memory.c
index de8bc85dc8f..109e9866237 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -47,6 +47,7 @@
#include <linux/pagemap.h>
#include <linux/rmap.h>
#include <linux/module.h>
+#include <linux/delayacct.h>
#include <linux/init.h>
#include <asm/pgalloc.h>
@@ -1934,6 +1935,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
migration_entry_wait(mm, pmd, address);
goto out;
}
+ delayacct_set_flag(DELAYACCT_PF_SWAPIN);
page = lookup_swap_cache(entry);
if (!page) {
swapin_readahead(entry, address, vma);
@@ -1946,6 +1948,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
if (likely(pte_same(*page_table, orig_pte)))
ret = VM_FAULT_OOM;
+ delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
goto unlock;
}
@@ -1955,6 +1958,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
grab_swap_token();
}
+ delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
mark_page_accessed(page);
lock_page(page);