Use memfd blocks for the srbchannel if:
- we have memfd support compiled in, and ..
- client supports PA protocol version >= 31, and ..
- client states that it can handle memfd shared memory
Otherwise fall-back to the regular POSIX shm_open() techniques.
Signed-off-by: Ahmed S. Darwish <darwish.07 at gmail.com>
---
PROTOCOL | 13 ++++++++++++
configure.ac | 2 +-
src/pulse/context.c | 29 +++++++++++++++++++++++---
src/pulse/internal.h | 2 ++
src/pulsecore/mem.h | 8 ++++++++
src/pulsecore/protocol-native.c | 45 ++++++++++++++++++++++++++++++++++++-----
6 files changed, 90 insertions(+), 9 deletions(-)
diff --git a/PROTOCOL b/PROTOCOL
index 3c08fea..1af0908 100644
--- a/PROTOCOL
+++ b/PROTOCOL
@@ -371,6 +371,19 @@ PA_COMMAND_DISABLE_SRBCHANNEL
Tells the client to stop listening on the additional SHM ringbuffer channel.
Acked by client by sending PA_COMMAND_DISABLE_SRBCHANNEL back.
+## v31, implemented by >= 9.0
+
+Second most-significant bit of the version tag is now used to flag
+memfd SHM support, for both client and server,
+
+For srbchannels, the server will use memfd communication if:
+
+- the server has memfd code compiled in, and ..
+- client supports protocol version >= 31, and ..
+- the client states that it can handle memfd shared memory
+
+Otherwise, regular posix SHM is used.
+
#### If you just changed the protocol, read this
## module-tunnel depends on the sink/source/sink-input/source-input protocol
## internals, so if you changed these, you might have broken module-tunnel.
diff --git a/configure.ac b/configure.ac
index 256a196..6bbee3f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -40,7 +40,7 @@ AC_SUBST(PA_MINOR, pa_minor)
AC_SUBST(PA_MAJORMINOR, pa_major.pa_minor)
AC_SUBST(PA_API_VERSION, 12)
-AC_SUBST(PA_PROTOCOL_VERSION, 30)
+AC_SUBST(PA_PROTOCOL_VERSION, 31)
# The stable ABI for client applications, for the version info x:y:z
# always will hold y=z
diff --git a/src/pulse/context.c b/src/pulse/context.c
index 39e1ae8..204c3e5 100644
--- a/src/pulse/context.c
+++ b/src/pulse/context.c
@@ -480,6 +480,7 @@ static void setup_complete_callback(pa_pdispatch *pd, uint32_t command, uint32_t
case PA_CONTEXT_AUTHORIZING: {
pa_tagstruct *reply;
bool shm_on_remote = false;
+ bool memfd_on_remote = false;
if (pa_tagstruct_getu32(t, &c->version) < 0 ||
!pa_tagstruct_eof(t)) {
@@ -498,7 +499,15 @@ static void setup_complete_callback(pa_pdispatch *pd, uint32_t command, uint32_t
not. */
if (c->version >= 13) {
shm_on_remote = !!(c->version & 0x80000000U);
- c->version &= 0x7FFFFFFFU;
+
+ /* Starting with protocol version 31, the second MSB of the version
+ * tag reflects whether memfd is supported on the other PA end. */
+ if (c->version >= 31)
+ memfd_on_remote = !!(c->version & 0x40000000U);
+
+ /* Reserve the two most-significant _bytes_ of the version tag
+ * for flags. */
+ c->version &= 0x0000FFFFU;
}
pa_log_debug("Protocol version: remote %u, local %u", c->version, PA_PROTOCOL_VERSION);
@@ -524,6 +533,18 @@ static void setup_complete_callback(pa_pdispatch *pd, uint32_t command, uint32_t
pa_log_debug("Negotiated SHM: %s", pa_yes_no(c->do_shm));
pa_pstream_enable_shm(c->pstream, c->do_shm);
+ c->shm_type = PA_MEM_TYPE_PRIVATE;
+ if (c->do_shm) {
+ if (c->version >= 31 && memfd_on_remote && pa_memfd_is_locally_supported()) {
+ pa_pstream_enable_memfd(c->pstream);
+ c->shm_type = PA_MEM_TYPE_SHARED_MEMFD;
+ } else
+ c->shm_type = PA_MEM_TYPE_SHARED_POSIX;
+ }
+
+ pa_log_debug("Memfd possible: %s", pa_yes_no(pa_memfd_is_locally_supported()));
+ pa_log_debug("Negotiated SHM type: %s", pa_mem_type_to_string(c->shm_type));
+
reply = pa_tagstruct_command(c, PA_COMMAND_SET_CLIENT_NAME, &tag);
if (c->version >= 13) {
@@ -591,8 +612,10 @@ static void setup_context(pa_context *c, pa_iochannel *io) {
pa_log_debug("SHM possible: %s", pa_yes_no(c->do_shm));
/* Starting with protocol version 13 we use the MSB of the version
- * tag for informing the other side if we could do SHM or not */
- pa_tagstruct_putu32(t, PA_PROTOCOL_VERSION | (c->do_shm ? 0x80000000U : 0));
+ * tag for informing the other side if we could do SHM or not.
+ * Starting from version 31, second MSB is used to flag memfd support. */
+ pa_tagstruct_putu32(t, PA_PROTOCOL_VERSION | (c->do_shm ? 0x80000000U : 0) |
+ (pa_memfd_is_locally_supported() ? 0x40000000 : 0));
pa_tagstruct_put_arbitrary(t, cookie, sizeof(cookie));
#ifdef HAVE_CREDS
diff --git a/src/pulse/internal.h b/src/pulse/internal.h
index eefd181..9c77c94 100644
--- a/src/pulse/internal.h
+++ b/src/pulse/internal.h
@@ -95,6 +95,8 @@ struct pa_context {
bool filter_added:1;
pa_spawn_api spawn_api;
+ pa_mem_type_t shm_type;
+
pa_strlist *server_list;
char *server;
diff --git a/src/pulsecore/mem.h b/src/pulsecore/mem.h
index d0a063c..d0538f4 100644
--- a/src/pulsecore/mem.h
+++ b/src/pulsecore/mem.h
@@ -56,4 +56,12 @@ static inline const char *pa_mem_type_to_string(pa_mem_type_t type) {
pa_assert_not_reached();
}
+static inline bool pa_memfd_is_locally_supported() {
+#ifdef HAVE_MEMFD
+ return true;
+#else
+ return false;
+#endif
+}
+
#endif
diff --git a/src/pulsecore/protocol-native.c b/src/pulsecore/protocol-native.c
index 58f99c1..1e6d61c 100644
--- a/src/pulsecore/protocol-native.c
+++ b/src/pulsecore/protocol-native.c
@@ -48,6 +48,7 @@
#include <pulsecore/core-scache.h>
#include <pulsecore/core-subscribe.h>
#include <pulsecore/log.h>
+#include <pulsecore/mem.h>
#include <pulsecore/strlist.h>
#include <pulsecore/shared.h>
#include <pulsecore/sample-util.h>
@@ -2596,11 +2597,12 @@ static void command_exit(pa_pdispatch *pd, uint32_t command, uint32_t tag, pa_ta
pa_pstream_send_simple_ack(c->pstream, tag); /* nonsense */
}
-static void setup_srbchannel(pa_native_connection *c) {
+static void setup_srbchannel(pa_native_connection *c, pa_mem_type_t shm_type) {
pa_srbchannel_template srbt;
pa_srbchannel *srb;
pa_memchunk mc;
pa_tagstruct *t;
+ const char *reason;
int fdlist[2];
if (!c->options->srbchannel) {
@@ -2618,11 +2620,21 @@ static void setup_srbchannel(pa_native_connection *c) {
return;
}
- if (!(c->rw_mempool = pa_mempool_new(PA_MEM_TYPE_SHARED_POSIX, c->protocol->core->shm_size))) {
+ if (!(c->rw_mempool = pa_mempool_new(shm_type, c->protocol->core->shm_size))) {
pa_log_warn("Disabling srbchannel, reason: Failed to allocate shared "
"writable memory pool.");
return;
}
+
+ if (shm_type == PA_MEM_TYPE_SHARED_MEMFD) {
+ if (pa_pstream_register_memfd_mempool(c->pstream, c->rw_mempool, &reason)) {
+ pa_log_warn("Disabling srbchannel, reason: Failed to register memfd mempool: %s", reason);
+
+ pa_mempool_free(c->rw_mempool);
+ c->rw_mempool = NULL;
+ return;
+ }
+ }
pa_mempool_set_is_remote_writable(c->rw_mempool, true);
srb = pa_srbchannel_new(c->protocol->core->mainloop, c->rw_mempool);
@@ -2670,7 +2682,9 @@ static void command_enable_srbchannel(pa_pdispatch *pd, uint32_t command, uint32
static void command_auth(pa_pdispatch *pd, uint32_t command, uint32_t tag, pa_tagstruct *t, void *userdata) {
pa_native_connection *c = PA_NATIVE_CONNECTION(userdata);
const void*cookie;
+ bool memfd_on_remote = false;
pa_tagstruct *reply;
+ pa_mem_type_t shm_type;
bool shm_on_remote = false, do_shm;
pa_native_connection_assert_ref(c);
@@ -2694,7 +2708,15 @@ static void command_auth(pa_pdispatch *pd, uint32_t command, uint32_t tag, pa_ta
not. */
if (c->version >= 13) {
shm_on_remote = !!(c->version & 0x80000000U);
- c->version &= 0x7FFFFFFFU;
+
+ /* Starting with protocol version 31, the second MSB of the version
+ * tag reflects whether memfd is supported on the other PA end. */
+ if (c->version >= 31)
+ memfd_on_remote = !!(c->version & 0x40000000U);
+
+ /* Reserve the two most-significant _bytes_ of the version tag
+ * for flags. */
+ c->version &= 0x0000FFFFU;
}
pa_log_debug("Protocol version: remote %u, local %u", c->version, PA_PROTOCOL_VERSION);
@@ -2781,8 +2803,21 @@ static void command_auth(pa_pdispatch *pd, uint32_t command, uint32_t tag, pa_ta
pa_log_debug("Negotiated SHM: %s", pa_yes_no(do_shm));
pa_pstream_enable_shm(c->pstream, do_shm);
+ shm_type = PA_MEM_TYPE_PRIVATE;
+ if (do_shm) {
+ if (c->version >= 31 && memfd_on_remote && pa_memfd_is_locally_supported()) {
+ shm_type = PA_MEM_TYPE_SHARED_MEMFD;
+ pa_pstream_enable_memfd(c->pstream);
+ } else
+ shm_type = PA_MEM_TYPE_SHARED_POSIX;
+
+ pa_log_debug("Memfd possible: %s", pa_yes_no(pa_memfd_is_locally_supported()));
+ pa_log_debug("Negotiated SHM type: %s", pa_mem_type_to_string(shm_type));
+ }
+
reply = reply_new(tag);
- pa_tagstruct_putu32(reply, PA_PROTOCOL_VERSION | (do_shm ? 0x80000000 : 0));
+ pa_tagstruct_putu32(reply, PA_PROTOCOL_VERSION | (do_shm ? 0x80000000 : 0) |
+ (pa_memfd_is_locally_supported() ? 0x40000000 : 0));
#ifdef HAVE_CREDS
{
@@ -2799,7 +2834,7 @@ static void command_auth(pa_pdispatch *pd, uint32_t command, uint32_t tag, pa_ta
pa_pstream_send_tagstruct(c->pstream, reply);
#endif
- setup_srbchannel(c);
+ setup_srbchannel(c, shm_type);
}
static void command_set_client_name(pa_pdispatch *pd, uint32_t command, uint32_t tag, pa_tagstruct *t, void *userdata) {
Regards,
--
Darwish
http://darwish.chasingpointers.com
