Hi Sean,
Thanks for reviewing the patches. Please find answers to your review
comments below:
On 2014-09-04 23:37, Hefty, Sean wrote:
Could you please go through the provided changes and ensure that
they are part of the regular rsocket head stream.
It would be helpful to separate patches into different email messages.
Sorry, it was my mistake. I have corrected it - now v2 of patches from
1 to 4 are
sent in different email messages with a subject template
"[PATCH v2 {patch_no}/4] rsockets: {short_description}".
Subject: [patch 1/3] subsystem: RDMA CM
commit 725d209ea390c643447c337b178442e5ef7b8b50
Author: Sreedhar Kodali <srkodali@xxxxxxxxxxxxxxxxxx>
Date: Tue Aug 5 16:18:58 2014 +0530
By default the R-Sockets pre-loading library intercepts all the
stream
and datagram sockets belonging to a launched program processes
and
threads.
However, distributed application and database servers may require
fine
grained interception to ensure that only the processes which are
listening
for remote connections on the RDMA transport need to be enabled
with
RDMA
while remaining can continue to use TCP as before. This allows
proper
communication happening between various server components
locally.
A configuration file based mechanism is introduced to facilitate
this
fine grained interception mechanism. As part of preload
initialization,
the configuration file is scanned and an in-memory record store
is
created
with all the entries found. When a request is made to intercept
a
socket,
its attributes are cross checked with stored records to see
whether
we
should proceed with rsocket switch over.
Note: Right now, the fine grained interception mechanism is
enabled
only
for newly created sockets. Going forward, this can be
extened
to
select connections based on the specified host/IP addresses
and
ports as well.
"preload_config" is the name of the configuration file which
should
exist
in the default configuration location (usually the full path to
this
configuration file is:
<install-root>/etc/rdma/rsocket/preload_config)
of an installed rsocket library.
The sample format for this configuration file is shown below:
@#
@# Sample config file for preloading in a program specific way
@#
@# Each line entry should have the following format:
@#
@# prog_name <space> dom_spec <space> type_spec <space>
proto_spec
@#
@# where,
@#
@# prog_name - program or command name (string without spaces)
@# dom_spec - one or more socket domain strings separated by
commas
@# - format: {*|domain,[,domain,...]}
@# - '*' means any valid domain
@# - valid domains: inet/inet6/ib
@# type_spec - one or more socket type strings separated by
commas
@# - format: {*|type[,type,...]}
@# - '*' means any valid type
@# - valid types: stream/dgram
@# proto_spec - one or more socket protocol strings separated by
commas
@# - format: {*|protocol[,protocol,...]}
@# - '*' means any valid protocol
@# - valid protocols: tcp/udp
@# <space> - one ore more tab or space characters
@#
@# Note:
@# Lines beginning with '#' character are treated as comments.
@# Comments at the end of an entry are allowed and should be
preceded
@# by '#' character.
@# Blank lines are ignored.
@
@progA inet stream tcp # intercept progA's internet stream
sockets
@progB inet6 dgram udp # intercept progB's ipv6 datagram sockets
@progC * * * # intercept progC's sockets
Signed-off-by: Sreedhar Kodali <srkodali@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Pradeep Satyanarayana <pradeeps@xxxxxxxxxxxxxxxxxx>
Overall, the patch concepts look reasonable. See comments below.
Thanks for your appreciation.
---
diff --git a/src/preload.c b/src/preload.c
index fb2149b..8c043aa 100644
--- a/src/preload.c
+++ b/src/preload.c
@@ -50,6 +50,8 @@
#include <netinet/tcp.h>
#include <unistd.h>
#include <semaphore.h>
+#include <ctype.h>
+#include <stdlib.h>
#include <rdma/rdma_cma.h>
#include <rdma/rdma_verbs.h>
@@ -57,6 +59,10 @@
#include "cma.h"
#include "indexer.h"
+#ifndef LINE_MAX
+#define LINE_MAX 2048
+#endif /* LINE_MAX */
Any reason why this can't just be an enum and a smaller value?
This can't be an enum because it is used in allocating temporary
buffer for line parsing.
Smaller value, yes.
Now in revised patch v2 1/4, I have replaced it with hard coded
value of 512. Hope this value covers most of the general
configuration cases.
+static config_entry_t *entryp = NULL;
+static int16_t nentries = 0;
+static int16_t config_scanned = 0;
+static int16_t config_avail = 0;
+extern char *program_invocation_short_name;
Static variables are initialized to 0 by default (C standard).
Yes, that's true. Just made them explicit for clarity.
In revised patch v2 1/4, the initialization are removed.
+/* free in-memory config store
+ * should be called only once during finalization
+ */
+static void free_preload_config(void)
+{
+ int i;
+
+ if (entryp) {
+ for (i = 0; i < nentries; i++) {
+ if (entryp[i].name) {
+ free(entryp[i].name);
+ }
+ }
+ free(entryp);
+ }
+
+ return;
+}
+
+/* check whether interception is required for this socket
+ * compares the provided attributes with that available in the
in-memory
+ * data store for the current process
+ * sets-up in-memory config store if it's already not done
+ */
+static int intercept_socket(int domain, int type, int protocol)
+{
+ int i;
+
+ if (!config_scanned) {
+ pthread_mutex_lock(&mut);
+ if (scan_preload_config() == 0) {
+ config_avail = 1;
+ }
+ if (entryp) {
+ atexit(free_preload_config);
+ }
+ config_scanned = 1;
+ pthread_mutex_unlock(&mut);
There's already an init_preload() function that handles all
initialization. Please move the scanning of the file there. You can
then drop the config_scanned variable.
Done. Please refer to patch v2 1/4.
Scanning of file is moved to init_preload() function.
config_scanned variable is now dropped.
+ }
+
+ if (!config_avail) {
+ return -1;
+ }
This can probably go. I'm not sure why the return value is -1, versus
just 1 or 0.
Done. Please refer to patch v2 1/4.
The return value of -1 is now removed and it's now replaced
with explicit config_avail checking in socket() method.
+
+ /* locate the config entry */
+ for (i = 0; i < nentries; i++) {
+ if (strncmp(entryp[i].name, program_invocation_short_name,
strlen(entryp[i].name)) == 0) {
+ break;
+ }
+ }
+ if (i == nentries) {
+ return 0;
+ }
+
+ /* match domain field */
+ if (!(entryp[i].domain & (1 << domain))) {
+ return 0;
+ }
+
+ /* match type field */
+ if (!(entryp[i].type & (1 << type))) {
+ return 0;
+ }
+
+ /* match protocol field only if protocol is specified */
+ if (protocol && !(entryp[i].protocol & (1 << protocol))) {
+ return 0;
+ }
+
+ /* entry matched */
+ return 1;
+}
+
static int fd_open(void)
{
struct fd_info *fdi;
@@ -404,6 +631,10 @@ int socket(int domain, int type, int protocol)
static __thread int recursive;
int index, ret;
+ if (intercept_socket(domain, type, protocol) == 0) {
+ goto real;
+ }
+
if (recursive)
goto real;
Subject: [patch 2/3] subsystem: RDMA CM
commit bf77b79be41b9ed288be6c7e858d463838febc84
Author: Sreedhar Kodali <srkodali@xxxxxxxxxxxxxxxxxx>
Date: Tue Aug 5 16:38:05 2014 +0530
Some complex server class applications start multiple listening
threads
to receive client connection requests simultaneously from
different
sources.
When rsocket tries to intercept sockets belonging to such
applications,
the listen() call made multiple times from different listening
threads
should not result in error on par with the corresponding TCP
behavior.
The return value of rlisten() is modified to ensure that it
wouldn't
bail out when it is invoked more than once with the same socket
attributes
from different listening threads. This behavior is gated by a
runtime
parameter 'multi_listeners' with the associated configuration
file
so it
does not affect in any way the rest of rsocket applications.
I didn't follow this. If rsocket is behaving differently than normal
sockets, I'm fine updating it so that it matches the desired behavior.
It doesn't need to be an option.
That said, can you provide more details on what the desired behavior
should be and what rsockets is doing differently?
Accepted. Your subsequent understanding and modified changes are
correct.
I am referring to your latest patch on this.
Signed-off-by: Sreedhar Kodali <srkodali@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Pradeep Satyanarayana <pradeeps@xxxxxxxxxxxxxxxxxx>
---
diff --git a/src/rsocket.c b/src/rsocket.c
index 7007897..3879a70 100644
--- a/src/rsocket.c
+++ b/src/rsocket.c
@@ -115,6 +115,7 @@ static uint16_t def_rqsize = 384;
static uint32_t def_mem = (1 << 17);
static uint32_t def_wmem = (1 << 17);
static uint32_t polling_time = 10;
+static uint16_t multi_listeners = 0;
/*
* Immediate data format is determined by the upper bits
@@ -542,6 +543,11 @@ void rs_configure(void)
def_iomap_size = (uint8_t) rs_value_to_scale(
(uint16_t) rs_scale_to_value(def_iomap_size, 8), 8);
}
+
+ if ((f = fopen(RS_CONF_DIR "/multi_listeners", "r"))) {
+ (void) fscanf(f, "%hu", &multi_listeners);
+ fclose(f);
+ }
init = 1;
out:
pthread_mutex_unlock(&mut);
@@ -1175,8 +1181,12 @@ int rlisten(int socket, int backlog)
if (!rs)
return ERR(EBADF);
ret = rdma_listen(rs->cm_id, backlog);
- if (!ret)
+ if (!ret) {
+ rs->state = rs_listening;
+ } else if (multi_listeners == 1 && errno == EINVAL) {
rs->state = rs_listening;
This is what I don't get. The listen called failed, but we want to
mark that the rsocket is in the listening state anyway?
Even though this logic is working, later I understood that this
is not the correct way of fixing the issue. As I said above,
your latest fix on this is good.
+ ret = 0;
+ }
return ret;
}
Subject: [patch 3/3] subsystem: RDMA CM
commit 275aafe76c98718ad6989cbe1cf35fb82e36cd2c
Author: Sreedhar Kodali <srkodali@xxxxxxxxxxxxxxxxxx>
Date: Tue Aug 5 16:45:41 2014 +0530
While waiting for a completion queue event, rsocket's logic by
default
bails out when interrupted. Because of this, on the passive side
ongoing connection establishments are abruptly terminated without
fully accepting the incoming connection requests.
The solution is to modify the completion event waiting logic to
ensure
that it retries for the event upon interruption instead of
returning
with an error. This behavior is gated by a runtime parameter
'restart_onintr' with the associated configuration file so it
does
not affect in any way the rest of rsocket applications.
Signed-off-by: Sreedhar Kodali <srkodali@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Pradeep Satyanarayana <pradeeps@xxxxxxxxxxxxxxxxxx>
---
diff --git a/src/rsocket.c b/src/rsocket.c
index 3879a70..c7e5b11 100644
--- a/src/rsocket.c
+++ b/src/rsocket.c
@@ -116,6 +116,7 @@ static uint32_t def_mem = (1 << 17);
static uint32_t def_wmem = (1 << 17);
static uint32_t polling_time = 10;
static uint16_t multi_listeners = 0;
+static uint16_t restart_onintr = 0;
/*
* Immediate data format is determined by the upper bits
@@ -548,6 +549,11 @@ void rs_configure(void)
(void) fscanf(f, "%hu", &multi_listeners);
fclose(f);
}
+
+ if ((f = fopen(RS_CONF_DIR "/restart_onintr", "r"))) {
+ (void) fscanf(f, "%hu", &restart_onintr);
+ fclose(f);
+ }
init = 1;
out:
pthread_mutex_unlock(&mut);
@@ -1973,10 +1979,14 @@ static int rs_get_cq_event(struct rsocket *rs)
if (!rs->cq_armed)
return 0;
+resume_get_cq_event:
ret = ibv_get_cq_event(rs->cm_id->recv_cq_channel, &cq,
&context);
if (!ret) {
ibv_ack_cq_events(rs->cm_id->recv_cq, 1);
rs->cq_armed = 0;
+ } else if (restart_onintr == 1 && errno == EINTR) {
+ errno = 0;
+ goto resume_get_cq_event;
Could this lead to the thread blocking forever? Is there a reason to
make this a conditional check?
Could be. This is made a conditional check because most of the cases
this is only useful on the server side.
} else if (errno != EAGAIN) {
rs->state = rs_error;
}
- Sean
Thank You.
- Sreedhar
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