[PATCH] cifs: ask for more credit on async read/write code paths

[Steve French <smfrench@xxxxxxxxx>]

When doing a large read or write workload we only
very gradually increase the number of credits
which can cause problems with parallelizing large i/o
(I/O ramps up more slowly than it should for large
read/write workloads) especially with multichannel
when the number of credits on the secondary channels
starts out low (e.g. less than about 130) or when
recovering after server throttled back the number
of credit.

Signed-off-by: Aurelien Aptel <aaptel@xxxxxxxx>
Reviewed-by: Shyam Prasad N <sprasad@xxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
 fs/cifs/smb2pdu.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 4bbb6126b14d..2199a9bfae8f 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -4041,8 +4041,7 @@ smb2_async_readv(struct cifs_readdata *rdata)
  if (rdata->credits.value > 0) {
  shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(rdata->bytes,
  SMB2_MAX_BUFFER_SIZE));
- shdr->CreditRequest =
- cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 1);
+ shdr->CreditRequest = cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 8);

  rc = adjust_credits(server, &rdata->credits, rdata->bytes);
  if (rc)
@@ -4348,8 +4347,7 @@ smb2_async_writev(struct cifs_writedata *wdata,
  if (wdata->credits.value > 0) {
  shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(wdata->bytes,
      SMB2_MAX_BUFFER_SIZE));
- shdr->CreditRequest =
- cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 1);
+ shdr->CreditRequest = cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 8);

  rc = adjust_credits(server, &wdata->credits, wdata->bytes);
  if (rc)

-- 
Thanks,

Steve

From 9084ef8ff9fa24029f48a949ff173ff0b7479110 Mon Sep 17 00:00:00 2001
From: Aurelien Aptel <aaptel@xxxxxxxx>
Date: Thu, 4 Mar 2021 17:51:48 +0000
Subject: [PATCH] cifs: ask for more credit on async read/write code paths

When doing a large read or write workload we only
very gradually increase the number of credits
which can cause problems with parallelizing large i/o
(I/O ramps up more slowly than it should for large
read/write workloads) especially with multichannel
when the number of credits on the secondary channels
starts out low (e.g. less than about 130) or when
recovering after server throttled back the number
of credit.

Signed-off-by: Aurelien Aptel <aaptel@xxxxxxxx>
Reviewed-by: Shyam Prasad N <sprasad@xxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
 fs/cifs/smb2pdu.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 4bbb6126b14d..2199a9bfae8f 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -4041,8 +4041,7 @@ smb2_async_readv(struct cifs_readdata *rdata)
 	if (rdata->credits.value > 0) {
 		shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(rdata->bytes,
 						SMB2_MAX_BUFFER_SIZE));
-		shdr->CreditRequest =
-			cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 1);
+		shdr->CreditRequest = cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 8);
 
 		rc = adjust_credits(server, &rdata->credits, rdata->bytes);
 		if (rc)
@@ -4348,8 +4347,7 @@ smb2_async_writev(struct cifs_writedata *wdata,
 	if (wdata->credits.value > 0) {
 		shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(wdata->bytes,
 						    SMB2_MAX_BUFFER_SIZE));
-		shdr->CreditRequest =
-			cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 1);
+		shdr->CreditRequest = cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 8);
 
 		rc = adjust_credits(server, &wdata->credits, wdata->bytes);
 		if (rc)
-- 
2.27.0