[PATCH] cifs: Do not use large smb buffers in response path
unless response is larger than 256 bytes. This cuts more than 1/3 of
the large memory allocations that cifs does and should be a huge help to
memory pressure under stress.
Signed-off-by: Steve French (sfrench@us.ibm.com)
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 383e55f..390f22f 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1,7 +1,7 @@
/*
* fs/cifs/connect.c
*
- * Copyright (C) International Business Machines Corp., 2002,2004
+ * Copyright (C) International Business Machines Corp., 2002,2005
* Author(s): Steve French (sfrench@us.ibm.com)
*
* This library is free software; you can redistribute it and/or modify
@@ -28,6 +28,7 @@
#include <linux/ctype.h>
#include <linux/utsname.h>
#include <linux/mempool.h>
+#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
#include "cifspdu.h"
@@ -198,6 +199,8 @@
int length;
unsigned int pdu_length, total_read;
struct smb_hdr *smb_buffer = NULL;
+ struct smb_hdr *bigbuf = NULL;
+ struct smb_hdr *smallbuf = NULL;
struct msghdr smb_msg;
struct kvec iov;
struct socket *csocket = server->ssocket;
@@ -206,6 +209,7 @@
struct task_struct *task_to_wake = NULL;
struct mid_q_entry *mid_entry;
char *temp;
+ int isLargeBuf = FALSE;
daemonize("cifsd");
allow_signal(SIGKILL);
@@ -223,17 +227,33 @@
}
while (server->tcpStatus != CifsExiting) {
- if (smb_buffer == NULL)
- smb_buffer = cifs_buf_get();
- else
- memset(smb_buffer, 0, sizeof (struct smb_hdr));
-
- if (smb_buffer == NULL) {
- cERROR(1,("Can not get memory for SMB response"));
- set_current_state(TASK_INTERRUPTIBLE);
- schedule_timeout(HZ * 3); /* give system time to free memory */
- continue;
+ if (bigbuf == NULL) {
+ bigbuf = cifs_buf_get();
+ if(bigbuf == NULL) {
+ cERROR(1,("No memory for large SMB response"));
+ msleep(3000);
+ /* retry will check if exiting */
+ continue;
+ }
+ } else if(isLargeBuf) {
+ /* we are reusing a dirtry large buf, clear its start */
+ memset(bigbuf, 0, sizeof (struct smb_hdr));
}
+
+ if (smallbuf == NULL) {
+ smallbuf = cifs_small_buf_get();
+ if(smallbuf == NULL) {
+ cERROR(1,("No memory for SMB response"));
+ msleep(1000);
+ /* retry will check if exiting */
+ continue;
+ }
+ /* beginning of smb buffer is cleared in our buf_get */
+ } else /* if existing small buf clear beginning */
+ memset(smallbuf, 0, sizeof (struct smb_hdr));
+
+ isLargeBuf = FALSE;
+ smb_buffer = smallbuf;
iov.iov_base = smb_buffer;
iov.iov_len = 4;
smb_msg.msg_control = NULL;
@@ -251,8 +271,7 @@
csocket = server->ssocket;
continue;
} else if ((length == -ERESTARTSYS) || (length == -EAGAIN)) {
- set_current_state(TASK_INTERRUPTIBLE);
- schedule_timeout(1); /* minimum sleep to prevent looping
+ msleep(1); /* minimum sleep to prevent looping
allowing socket to clear and app threads to set
tcpStatus CifsNeedReconnect if server hung */
continue;
@@ -295,8 +314,7 @@
} else {
/* give server a second to
clean up before reconnect attempt */
- set_current_state(TASK_INTERRUPTIBLE);
- schedule_timeout(HZ);
+ msleep(1000);
/* always try 445 first on reconnect
since we get NACK on some if we ever
connected to port 139 (the NACK is
@@ -325,6 +343,11 @@
wake_up(&server->response_q);
continue;
} else { /* length ok */
+ if(pdu_length > MAX_CIFS_HDR_SIZE - 4) {
+ isLargeBuf = TRUE;
+ memcpy(bigbuf, smallbuf, 4);
+ smb_buffer = bigbuf;
+ }
length = 0;
iov.iov_base = 4 + (char *)smb_buffer;
iov.iov_len = pdu_length;
@@ -377,6 +400,10 @@
}
spin_unlock(&GlobalMid_Lock);
if (task_to_wake) {
+ if(isLargeBuf)
+ bigbuf = NULL;
+ else
+ smallbuf = NULL;
smb_buffer = NULL; /* will be freed by users thread after he is done */
wake_up_process(task_to_wake);
} else if (is_valid_oplock_break(smb_buffer) == FALSE) {
@@ -406,15 +433,17 @@
and get out of SendReceive. */
wake_up_all(&server->request_q);
/* give those requests time to exit */
- set_current_state(TASK_INTERRUPTIBLE);
- schedule_timeout(HZ/8);
-
+ msleep(125);
+
if(server->ssocket) {
sock_release(csocket);
server->ssocket = NULL;
}
- if (smb_buffer) /* buffer usually freed in free_mid - need to free it on error or exit */
- cifs_buf_release(smb_buffer);
+ /* buffer usuallly freed in free_mid - need to free it here on exit */
+ if (bigbuf != NULL)
+ cifs_buf_release(bigbuf);
+ if (smallbuf != NULL)
+ cifs_small_buf_release(smallbuf);
read_lock(&GlobalSMBSeslock);
if (list_empty(&server->pending_mid_q)) {
@@ -444,17 +473,15 @@
}
spin_unlock(&GlobalMid_Lock);
read_unlock(&GlobalSMBSeslock);
- set_current_state(TASK_INTERRUPTIBLE);
/* 1/8th of sec is more than enough time for them to exit */
- schedule_timeout(HZ/8);
+ msleep(125);
}
if (list_empty(&server->pending_mid_q)) {
/* mpx threads have not exited yet give them
at least the smb send timeout time for long ops */
cFYI(1, ("Wait for exit from demultiplex thread"));
- set_current_state(TASK_INTERRUPTIBLE);
- schedule_timeout(46 * HZ);
+ msleep(46);
/* if threads still have not exited they are probably never
coming home not much else we can do but free the memory */
}
@@ -469,9 +496,8 @@
length + cifs_min_rcv,
GFP_KERNEL);
}
-
- set_current_state(TASK_INTERRUPTIBLE);
- schedule_timeout(HZ/4);
+
+ msleep(250);
return 0;
}