smbd: High CPU usage
Jeremy Allison
jra at samba.org
Wed Jul 18 23:16:46 UTC 2018
On Wed, Jul 18, 2018 at 09:20:10PM +0300, Vadim Lazovskiy via samba-technical wrote:
> I would not agree.
> sendfile is great. It makes you able to serve content directly from disk to
> network without unnessesery copying to userspace. It saves you lots
> syscalls and context switching.
> As for our workload profile (1-2Gbit per server) it really saves CPU time.
>
> If someone of samba developers treat this as bug and eager to fix it I
> could provide extra information and do some debugging.
Here is a full patchset that should handle all platforms
for which we support sendfile(). Can you try it out and confirm it
fixes your issue ?
I logged:
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13537
to track this.
Jeremy.
-------------- next part --------------
From f0ed4f0930673ee044f187085e8972b8be104ebd Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Wed, 18 Jul 2018 13:32:49 -0700
Subject: [PATCH 1/5] s3: smbd: Fix Linux sendfile() for SMB2. Ensure we don't
spin on EAGAIN.
For SMB2 the socket is set non-blocking. Ensure sendfile()
calls complete by saving the socket state, setting it blocking,
doing the sendfile until completion and then restoring the socket
state.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13537
Signed-off-by: Jeremy Allison <jra at samba.org>
---
source3/lib/sendfile.c | 54 ++++++++++++++++++++++++++++++++++++------
1 file changed, 47 insertions(+), 7 deletions(-)
diff --git a/source3/lib/sendfile.c b/source3/lib/sendfile.c
index 3d457bd6f13..a578a66e7de 100644
--- a/source3/lib/sendfile.c
+++ b/source3/lib/sendfile.c
@@ -24,6 +24,7 @@
*/
#include "includes.h"
+#include "system/filesys.h"
#if defined(LINUX_SENDFILE_API)
@@ -36,8 +37,23 @@
ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset, size_t count)
{
size_t total=0;
- ssize_t ret;
+ ssize_t ret = -1;
size_t hdr_len = 0;
+ int saved_errno = 0;
+ int old_flags = 0;
+
+ /*
+ * Sendfile must complete before we can
+ * send any other outgoing data on the socket.
+ * Ensure socket is in blocking mode.
+ * For SMB2 by default the socket is in non-blocking
+ * mode.
+ */
+ old_flags = fcntl(tofd, F_GETFL, 0);
+ ret = set_blocking(tofd, true);
+ if (ret == -1) {
+ goto out;
+ }
/*
* Send the header first.
@@ -48,8 +64,9 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
hdr_len = header->length;
while (total < hdr_len) {
ret = sys_send(tofd, header->data + total,hdr_len - total, MSG_MORE);
- if (ret == -1)
- return -1;
+ if (ret == -1) {
+ goto out;
+ }
total += ret;
}
}
@@ -59,7 +76,7 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
ssize_t nwritten;
do {
nwritten = sendfile(tofd, fromfd, &offset, total);
- } while (nwritten == -1 && (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK));
+ } while (nwritten == -1 && errno == EINTR);
if (nwritten == -1) {
if (errno == ENOSYS || errno == EINVAL) {
/* Ok - we're in a world of pain here. We just sent
@@ -72,17 +89,40 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
*/
errno = EINTR; /* Normally we can never return this. */
}
- return -1;
+ ret = -1;
+ goto out;
}
if (nwritten == 0) {
/*
* EOF, return a short read
*/
- return hdr_len + (count - total);
+ ret = hdr_len + (count - total);
+ goto out;
}
total -= nwritten;
}
- return count + hdr_len;
+
+ ret = count + hdr_len;
+
+ out:
+
+ if (ret == -1) {
+ saved_errno = errno;
+ }
+
+ {
+ /* Restore the blocking state of the socket. */
+ int err = fcntl(tofd, F_SETFL, old_flags);
+ if (err == -1) {
+ return -1;
+ }
+ }
+
+ if (ret == -1) {
+ errno = saved_errno;
+ }
+
+ return ret;
}
#elif defined(SOLARIS_SENDFILE_API)
--
2.18.0.203.gfac676dfb9-goog
From abc681420b88a2d795adc44808c7e52eb2775cf6 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Wed, 18 Jul 2018 15:29:37 -0700
Subject: [PATCH 2/5] s3: smbd: Fix Solaris sendfile() for SMB2. Ensure we
don't spin on EAGAIN.
For SMB2 the socket is set non-blocking. Ensure sendfile()
calls complete by saving the socket state, setting it blocking,
doing the sendfile until completion and then restoring the socket
state.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13537
Signed-off-by: Jeremy Allison <jra at samba.org>
---
source3/lib/sendfile.c | 52 +++++++++++++++++++++++++++++++++++++-----
1 file changed, 46 insertions(+), 6 deletions(-)
diff --git a/source3/lib/sendfile.c b/source3/lib/sendfile.c
index a578a66e7de..6c323213830 100644
--- a/source3/lib/sendfile.c
+++ b/source3/lib/sendfile.c
@@ -139,6 +139,9 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
size_t total, xferred;
struct sendfilevec vec[2];
ssize_t hdr_len = 0;
+ int saved_errno = 0;
+ int old_flags = 0;
+ ssize_t ret = -1;
if (header) {
sfvcnt = 2;
@@ -164,6 +167,19 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
total = count + hdr_len;
+ /*
+ * Sendfile must complete before we can
+ * send any other outgoing data on the socket.
+ * Ensure socket is in blocking mode.
+ * For SMB2 by default the socket is in non-blocking
+ * mode.
+ */
+ old_flags = fcntl(tofd, F_GETFL, 0);
+ ret = set_blocking(tofd, true);
+ if (ret == -1) {
+ goto out;
+ }
+
while (total) {
ssize_t nwritten;
@@ -175,17 +191,21 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
xferred = 0;
nwritten = sendfilev(tofd, vec, sfvcnt, &xferred);
- if (nwritten == -1 && (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) {
+ if (nwritten == -1 && errno == EINTR) {
if (xferred == 0)
continue; /* Nothing written yet. */
else
nwritten = xferred;
}
- if (nwritten == -1)
- return -1;
- if (nwritten == 0)
- return -1; /* I think we're at EOF here... */
+ if (nwritten == -1) {
+ ret = -1;
+ goto out;
+ }
+ if (nwritten == 0) {
+ ret = -1;
+ goto out; /* I think we're at EOF here... */
+ }
/*
* If this was a short (signal interrupted) write we may need
@@ -207,7 +227,27 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
}
total -= nwritten;
}
- return count + hdr_len;
+ ret = count + hdr_len;
+
+ out:
+
+ if (ret == -1) {
+ saved_errno = errno;
+ }
+
+ {
+ /* Restore the blocking state of the socket. */
+ int err = fcntl(tofd, F_SETFL, old_flags);
+ if (err == -1) {
+ return -1;
+ }
+ }
+
+ if (ret == -1) {
+ errno = saved_errno;
+ }
+
+ return ret;
}
#elif defined(HPUX_SENDFILE_API)
--
2.18.0.203.gfac676dfb9-goog
From 0068f7d136da89d96d50dced5eda8738c28e2938 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Wed, 18 Jul 2018 15:36:47 -0700
Subject: [PATCH 3/5] s3: smbd: Fix HPUX sendfile() for SMB2. Ensure we don't
spin on EAGAIN.
For SMB2 the socket is set non-blocking. Ensure sendfile()
calls complete by saving the socket state, setting it blocking,
doing the sendfile until completion and then restoring the socket
state.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13537
Signed-off-by: Jeremy Allison <jra at samba.org>
---
source3/lib/sendfile.c | 53 +++++++++++++++++++++++++++++++++++++-----
1 file changed, 47 insertions(+), 6 deletions(-)
diff --git a/source3/lib/sendfile.c b/source3/lib/sendfile.c
index 6c323213830..63f50d1946f 100644
--- a/source3/lib/sendfile.c
+++ b/source3/lib/sendfile.c
@@ -260,6 +260,9 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
size_t total=0;
struct iovec hdtrl[2];
size_t hdr_len = 0;
+ int saved_errno = 0;
+ int old_flags = 0;
+ ssize_t ret = -1;
if (header) {
/* Set up the header/trailer iovec. */
@@ -273,6 +276,20 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
hdtrl[1].iov_len = 0;
total = count;
+
+ /*
+ * Sendfile must complete before we can
+ * send any other outgoing data on the socket.
+ * Ensure socket is in blocking mode.
+ * For SMB2 by default the socket is in non-blocking
+ * mode.
+ */
+ old_flags = fcntl(tofd, F_GETFL, 0);
+ ret = set_blocking(tofd, true);
+ if (ret == -1) {
+ goto out;
+ }
+
while (total + hdtrl[0].iov_len) {
ssize_t nwritten;
@@ -285,11 +302,15 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
do {
nwritten = sendfile(tofd, fromfd, offset, total, &hdtrl[0], 0);
- } while (nwritten == -1 && (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK));
- if (nwritten == -1)
- return -1;
- if (nwritten == 0)
- return -1; /* I think we're at EOF here... */
+ } while (nwritten == -1 && errno == EINTR);
+ if (nwritten == -1) {
+ ret = -1;
+ goto out;
+ }
+ if (nwritten == 0) {
+ ret = -1; /* I think we're at EOF here... */
+ goto out;
+ }
/*
* If this was a short (signal interrupted) write we may need
@@ -313,7 +334,27 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
total -= nwritten;
offset += nwritten;
}
- return count + hdr_len;
+ ret = count + hdr_len;
+
+ out:
+
+ if (ret == -1) {
+ saved_errno = errno;
+ }
+
+ {
+ /* Restore the blocking state of the socket. */
+ int err = fcntl(tofd, F_SETFL, old_flags);
+ if (err == -1) {
+ return -1;
+ }
+ }
+
+ if (ret == -1) {
+ errno = saved_errno;
+ }
+
+ return ret;
}
#elif defined(FREEBSD_SENDFILE_API) || defined(DARWIN_SENDFILE_API)
--
2.18.0.203.gfac676dfb9-goog
From 8df7360c2198098a2cb757910974110e33e4d4cf Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Wed, 18 Jul 2018 15:44:34 -0700
Subject: [PATCH 4/5] s3: smbd: Fix FreeBSD sendfile() for SMB2. Ensure we
don't spin on EAGAIN.
For SMB2 the socket is set non-blocking. Ensure sendfile()
calls complete by saving the socket state, setting it blocking,
doing the sendfile until completion and then restoring the socket
state.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13537
Signed-off-by: Jeremy Allison <jra at samba.org>
---
source3/lib/sendfile.c | 44 ++++++++++++++++++++++++++++++++++++++----
1 file changed, 40 insertions(+), 4 deletions(-)
diff --git a/source3/lib/sendfile.c b/source3/lib/sendfile.c
index 63f50d1946f..575428deb15 100644
--- a/source3/lib/sendfile.c
+++ b/source3/lib/sendfile.c
@@ -368,9 +368,11 @@ ssize_t sys_sendfile(int tofd, int fromfd,
{
struct sf_hdtr sf_header = {0};
struct iovec io_header = {0};
+ int saved_errno = 0;
+ int old_flags = 0;
off_t nwritten;
- int ret;
+ ssize_t ret = -1;
if (header) {
sf_header.headers = &io_header;
@@ -381,6 +383,19 @@ ssize_t sys_sendfile(int tofd, int fromfd,
sf_header.trl_cnt = 0;
}
+ /*
+ * Sendfile must complete before we can
+ * send any other outgoing data on the socket.
+ * Ensure socket is in blocking mode.
+ * For SMB2 by default the socket is in non-blocking
+ * mode.
+ */
+ old_flags = fcntl(tofd, F_GETFL, 0);
+ ret = set_blocking(tofd, true);
+ if (ret == -1) {
+ goto out;
+ }
+
while (count != 0) {
nwritten = count;
@@ -391,9 +406,10 @@ ssize_t sys_sendfile(int tofd, int fromfd,
#else
ret = sendfile(fromfd, tofd, offset, count, &sf_header, &nwritten, 0);
#endif
- if (ret == -1 && errno != EINTR && errno != EAGAIN && errno != EWOULDBLOCK) {
+ if (ret == -1 && errno != EINTR) {
/* Send failed, we are toast. */
- return -1;
+ ret = -1;
+ goto out;
}
if (nwritten == 0) {
@@ -420,7 +436,27 @@ ssize_t sys_sendfile(int tofd, int fromfd,
count -= nwritten;
}
- return nwritten;
+ ret = nwritten;
+
+ out:
+
+ if (ret == -1) {
+ saved_errno = errno;
+ }
+
+ {
+ /* Restore the blocking state of the socket. */
+ int err = fcntl(tofd, F_SETFL, old_flags);
+ if (err == -1) {
+ return -1;
+ }
+ }
+
+ if (ret == -1) {
+ errno = saved_errno;
+ }
+
+ return ret;
}
#elif defined(AIX_SENDFILE_API)
--
2.18.0.203.gfac676dfb9-goog
From 019c677b42184d5f45931bdb549b22aad25ee2e9 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra at samba.org>
Date: Wed, 18 Jul 2018 15:49:29 -0700
Subject: [PATCH 5/5] s3: smbd: Fix AIX sendfile() for SMB2. Ensure we don't
spin on EAGAIN.
For SMB2 the socket is set non-blocking. Ensure sendfile()
calls complete by saving the socket state, setting it blocking,
doing the sendfile until completion and then restoring the socket
state.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13537
Signed-off-by: Jeremy Allison <jra at samba.org>
---
source3/lib/sendfile.c | 45 +++++++++++++++++++++++++++++++++++++-----
1 file changed, 40 insertions(+), 5 deletions(-)
diff --git a/source3/lib/sendfile.c b/source3/lib/sendfile.c
index 575428deb15..a28102b5bf9 100644
--- a/source3/lib/sendfile.c
+++ b/source3/lib/sendfile.c
@@ -469,6 +469,9 @@ ssize_t sys_sendfile(int tofd, int fromfd,
ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset, size_t count)
{
struct sf_parms hdtrl;
+ int saved_errno = 0;
+ int old_flags = 0;
+ ssize_t ret = -1;
/* Set up the header/trailer struct params. */
if (header) {
@@ -485,9 +488,20 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
hdtrl.file_offset = offset;
hdtrl.file_bytes = count;
- while ( hdtrl.file_bytes + hdtrl.header_length ) {
- ssize_t ret;
+ /*
+ * Sendfile must complete before we can
+ * send any other outgoing data on the socket.
+ * Ensure socket is in blocking mode.
+ * For SMB2 by default the socket is in non-blocking
+ * mode.
+ */
+ old_flags = fcntl(tofd, F_GETFL, 0);
+ ret = set_blocking(tofd, true);
+ if (ret == -1) {
+ goto out;
+ }
+ while ( hdtrl.file_bytes + hdtrl.header_length ) {
/*
Return Value
@@ -505,12 +519,33 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
*/
do {
ret = send_file(&tofd, &hdtrl, 0);
- } while ((ret == 1) || (ret == -1 && (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)));
- if ( ret == -1 )
+ } while ((ret == 1) || (ret == -1 && errno == EINTR));
+ if ( ret == -1 ) {
+ goto out;
+ }
+ }
+
+ ret = count + header->length;
+
+ out:
+
+ if (ret == -1) {
+ saved_errno = errno;
+ }
+
+ {
+ /* Restore the blocking state of the socket. */
+ int err = fcntl(tofd, F_SETFL, old_flags);
+ if (err == -1) {
return -1;
+ }
}
- return count + header->length;
+ if (ret == -1) {
+ errno = saved_errno;
+ }
+
+ return ret;
}
/* END AIX SEND_FILE */
--
2.18.0.203.gfac676dfb9-goog
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