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[PATCH] cifs: Do not use large smb buffers in response path
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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>
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Steve French authored and Linus Torvalds committed Apr 29, 2005
1 parent c81156d commit b8643e1
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Showing 3 changed files with 65 additions and 33 deletions.
11 changes: 7 additions & 4 deletions fs/cifs/cifs_debug.c
View file
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
/*
* 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)
*
Expand Down Expand Up @@ -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",
Expand Down Expand Up @@ -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 =
Expand Down
80 changes: 53 additions & 27 deletions fs/cifs/connect.c
View file
Original file line number Diff line number Diff line change
@@ -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
Expand All @@ -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"
Expand Down Expand Up @@ -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;
Expand All @@ -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);
Expand All @@ -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 (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;
Expand All @@ -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;
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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)) {
Expand Down Expand Up @@ -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 */
}
Expand All @@ -469,9 +496,8 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
length + cifs_min_rcv,
GFP_KERNEL);
}

set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(HZ/4);

msleep(250);
return 0;
}

Expand Down
7 changes: 5 additions & 2 deletions fs/cifs/transport.c
View file
Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
/*
* 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
Expand Down Expand Up @@ -79,7 +79,10 @@ DeleteMidQEntry(struct mid_q_entry *midEntry)
list_del(&midEntry->qhead);
atomic_dec(&midCount);
spin_unlock(&GlobalMid_Lock);
cifs_buf_release(midEntry->resp_buf);
if(midEntry->largeBuf)
cifs_buf_release(midEntry->resp_buf);
else
cifs_small_buf_release(midEntry->resp_buf);
mempool_free(midEntry, cifs_mid_poolp);
}

Expand Down

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