[PATCH 10/13] add module parameter for users who need more outstanding I/O

Ed L. Cashin
2007-12-20T22:19:56Z

An AoE target provides an estimate of the number of outstanding
commands that the AoE initiator can send before getting a response.
The aoe_maxout parameter provides a way to set an even lower limit.
It will not allow a user to use more outstanding commands than the
target permits. If a user discovers a problem with a large setting,
this parameter provides a way for us to work with them to debug the
problem. We expect to improve the dynamic window sizing algorithm and
drop this parameter. For the time being, it is a debugging aid.

Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
---
drivers/block/aoe/aoecmd.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 7a96183..e92d885 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -18,6 +18,11 @@ static int aoe_deadsecs = 60 * 3;
module_param(aoe_deadsecs, int, 0644);
MODULE_PARM_DESC(aoe_deadsecs, "After aoe_deadsecs seconds, give up and fail dev.");

+static int aoe_maxout = 16;
+module_param(aoe_maxout, int, 0644);
+MODULE_PARM_DESC(aoe_maxout,
+ "Only aoe_maxout outstanding packets for every MAC on eX.Y.");
+
static struct sk_buff *
new_skb(ulong len)
{
@@ -984,7 +989,6 @@ aoecmd_cfg_rsp(struct sk_buff *skb)
struct aoeif *ifp;
ulong flags, sysminor, aoemajor;
struct sk_buff *sl;
- enum { MAXFRAMES = 16 };
u16 n;

h = (struct aoe_hdr *) skb_mac_header(skb);
@@ -1009,8 +1013,8 @@ aoecmd_cfg_rsp(struct sk_buff *skb)
}

n = be16_to_cpu(ch->bufcnt);
- if (n > MAXFRAMES) /* keep it reasonable */
- n = MAXFRAMES;
+ if (n > aoe_maxout) /* keep it reasonable */
+ n = aoe_maxout;

d = aoedev_by_sysminor_m(sysminor);
if (d == NULL) {
--
1.5.3.4