[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>
diff --git a/mm/memory.c b/mm/memory.c
index de8bc85..109e986 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 @@
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 @@
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 @@
grab_swap_token();
}
+ delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
mark_page_accessed(page);
lock_page(page);