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Commit b8643e1b authored by Steve French's avatar Steve French Committed by Linus Torvalds
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[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: default avatarSteve French <(sfrench@us.ibm.com)>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c81156dd

fs/cifs/cifs_debug.c

+7 −4
Original line number Diff line number Diff line 
/*

 *   fs/cifs_debug.c

 *

 *   Copyright (C) International Business Machines  Corp., 2000,2003

 *   Copyright (C) International Business Machines  Corp., 2000,2005

 *

 *   Modified by Steve French (sfrench@us.ibm.com)

 *
@@ -92,8 +92,10 @@ cifs_debug_data_read(char *buf, char **beginBuffer, off_t offset, 
		length =

		    sprintf(buf,

			    "\n%d) Name: %s  Domain: %s Mounts: %d ServerOS: %s  \n\tServerNOS: %s\tCapabilities: 0x%x\n\tSMB session status: %d\t",

				i, ses->serverName, ses->serverDomain, atomic_read(&ses->inUse),

				ses->serverOS, ses->serverNOS, ses->capabilities,ses->status);

				i, ses->serverName, ses->serverDomain,

				atomic_read(&ses->inUse),

				ses->serverOS, ses->serverNOS,

				ses->capabilities,ses->status);

		buf += length;

		if(ses->server) {

			buf += sprintf(buf, "TCP status: %d\n\tLocal Users To Server: %d SecMode: 0x%x Req Active: %d",
@@ -207,7 +209,8 @@ cifs_stats_read(char *buf, char **beginBuffer, off_t offset, 
	buf += item_length;      

	item_length = 

		sprintf(buf,"SMB Request/Response Buffer: %d Pool size: %d\n",

			bufAllocCount.counter,cifs_min_rcv + tcpSesAllocCount.counter);

			bufAllocCount.counter,

			cifs_min_rcv + tcpSesAllocCount.counter);

	length += item_length;

	buf += item_length;

	item_length =

fs/cifs/connect.c

+53 −27
Original line number Diff line number Diff line 
/*

 *   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 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
	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 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
	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 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
	}



	while (server->tcpStatus != CifsExiting) {

		if (smb_buffer == NULL)

			smb_buffer = cifs_buf_get();

		else

			memset(smb_buffer, 0, sizeof (struct smb_hdr));

		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 (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 */

		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 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
			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 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
				} 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 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
					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 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
				}

				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 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
	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 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
		}

		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 */

	}
@@ -470,8 +497,7 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server) 
			GFP_KERNEL);

	}

	

	set_current_state(TASK_INTERRUPTIBLE);

	schedule_timeout(HZ/4);

	msleep(250);

	return 0;

}

fs/cifs/transport.c

+5 −2
Original line number Diff line number Diff line 
/*

 *   fs/cifs/transport.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
@@ -79,7 +79,10 @@ DeleteMidQEntry(struct mid_q_entry *midEntry) 
	list_del(&midEntry->qhead);

	atomic_dec(&midCount);

	spin_unlock(&GlobalMid_Lock);

	if(midEntry->largeBuf)

		cifs_buf_release(midEntry->resp_buf);

	else

		cifs_small_buf_release(midEntry->resp_buf);

	mempool_free(midEntry, cifs_mid_poolp);

}