This is a note to let you know that I've just added the patch titled
ethernet/arc/arc_emac: Fix huge delays in large file copies
to the 3.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ethernet-arc-arc_emac-fix-huge-delays-in-large-file-copies.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 08f32839287cd34a6777a3d2e390fbb9de04017a Mon Sep 17 00:00:00 2001
From: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx>
Date: Wed, 4 Sep 2013 17:17:15 +0530
Subject: ethernet/arc/arc_emac: Fix huge delays in large file copies
From: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx>
[ Upstream commit 27082ee1b92f4d41e78b85fe40f6ab39673fba00 ]
copying large files to a NFS mounted host was taking absurdly large
time.
Turns out that TX BD reclaim had a sublte bug.
Loop starts off from @txbd_dirty cursor and stops when it hits a BD
still in use by controller. However when it stops it needs to keep the
cursor at that very BD to resume scanning in next iteration. However it
was erroneously incrementing the cursor, causing the next scan(s) to
fail too, unless the BD chain was completely drained out.
[ARCLinux]$ ls -l -sh /disk/log.txt
17976 -rw-r--r-- 1 root root 17.5M Sep /disk/log.txt
========== Before =====================
[ARCLinux]$ time cp /disk/log.txt /mnt/.
real 31m 7.95s
user 0m 0.00s
sys 0m 0.10s
========== After =====================
[ARCLinux]$ time cp /disk/log.txt /mnt/.
real 0m 24.33s
user 0m 0.00s
sys 0m 0.19s
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Cc: Alexey Brodkin <abrodkin@xxxxxxxxxxxx> (commit_signer:3/4=75%)
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> (commit_signer:3/4=75%)
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: arc-linux-dev@xxxxxxxxxxxx
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/arc/emac_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/arc/emac_main.c
+++ b/drivers/net/ethernet/arc/emac_main.c
@@ -149,8 +149,6 @@ static void arc_emac_tx_clean(struct net
struct sk_buff *skb = tx_buff->skb;
unsigned int info = le32_to_cpu(txbd->info);
- *txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM;
-
if ((info & FOR_EMAC) || !txbd->data)
break;
@@ -180,6 +178,8 @@ static void arc_emac_tx_clean(struct net
txbd->data = 0;
txbd->info = 0;
+ *txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM;
+
if (netif_queue_stopped(ndev))
netif_wake_queue(ndev);
}
Patches currently in stable-queue which might be from Vineet.Gupta1@xxxxxxxxxxxx are
queue-3.11/ethernet-arc-arc_emac-fix-huge-delays-in-large-file-copies.patch
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