Re: [PATCH] mm/vmscan: Do not block forever atshrink_inactive_list().

[Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>]

Tetsuo Handa wrote:
> Dave, if you are OK with this updated patch, please let me know commit ID of 
> your patch.

I overlooked that too_many_isolated() in mm/vmscan.c already has

  if (current_is_kswapd())
    return 0;

lines. Therefore, it turned out that my patch is irrelevant to XFS issue.
Does patch shown below make sense?

Regards.
----------
>From e133aadd65df3d8622efced3443888ed3e60327b Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Mon, 26 May 2014 20:37:12 +0900
Subject: [PATCH] mm/vmscan: Do not throttle when hibernation_mode != 0.

In shrink_inactive_list(), we do not insert delay at

  if (!sc->hibernation_mode && !current_is_kswapd())
    wait_iff_congested(zone, BLK_RW_ASYNC, HZ/10);

if sc->hibernation_mode != 0.
Follow the same reason, we should not insert delay at

  while (unlikely(too_many_isolated(zone, file, sc))) {
    congestion_wait(BLK_RW_ASYNC, HZ/10);

    /* We are about to die and free our memory. Return now. */
    if (fatal_signal_pending(current))
      return SWAP_CLUSTER_MAX;
  }

if sc->hibernation_mode != 0.

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
 mm/vmscan.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 32c661d..89c42ca 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1362,6 +1362,9 @@ static int too_many_isolated(struct zone *zone, int file,
        if (current_is_kswapd())
                return 0;
 
+       if (sc->hibernation_mode)
+               return 0;
+
        if (!global_reclaim(sc))
                return 0;
 
-- 
1.7.1