consumerd: move address computation from on_read_subbuffer_mmap
authorJérémie Galarneau <jeremie.galarneau@efficios.com>
Mon, 4 May 2020 22:21:48 +0000 (18:21 -0400)
committerJérémie Galarneau <jeremie.galarneau@efficios.com>
Tue, 26 May 2020 20:25:31 +0000 (16:25 -0400)
The computation of the subbuffer's address is moved outside of
lttng_consumer_on_read_subbuffer_mmap to make it usable with a regular
buffer. This facilitates an upcoming change.

Moreover this has the benefit of isolating domain-specific logic from
this function which is supposed to be domain-agnostic.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I16f8ccaa73804f98fa03e69136548e6d6b7782e5

src/common/consumer/consumer.c
src/common/consumer/consumer.h
src/common/kernel-consumer/kernel-consumer.c
src/common/ust-consumer/ust-consumer.c
src/common/ust-consumer/ust-consumer.h

index c043353b9e82b078d235aa55a0b90f85d452fb73..64057c785f9512d734ccbd78649214125fad824d 100644 (file)
@@ -1670,12 +1670,12 @@ end:
  */
 ssize_t lttng_consumer_on_read_subbuffer_mmap(
                struct lttng_consumer_local_data *ctx,
-               struct lttng_consumer_stream *stream, unsigned long len,
+               struct lttng_consumer_stream *stream,
+               const char *buffer,
+               unsigned long len,
                unsigned long padding,
                struct ctf_packet_index *index)
 {
-       unsigned long mmap_offset;
-       void *mmap_base;
        ssize_t ret = 0;
        off_t orig_offset = stream->out_fd_offset;
        /* Default is on the disk */
@@ -1697,36 +1697,6 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                }
        }
 
-       /* get the offset inside the fd to mmap */
-       switch (consumer_data.type) {
-       case LTTNG_CONSUMER_KERNEL:
-               mmap_base = stream->mmap_base;
-               ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
-               if (ret < 0) {
-                       PERROR("tracer ctl get_mmap_read_offset");
-                       goto end;
-               }
-               break;
-       case LTTNG_CONSUMER32_UST:
-       case LTTNG_CONSUMER64_UST:
-               mmap_base = lttng_ustctl_get_mmap_base(stream);
-               if (!mmap_base) {
-                       ERR("read mmap get mmap base for stream %s", stream->name);
-                       ret = -EPERM;
-                       goto end;
-               }
-               ret = lttng_ustctl_get_mmap_read_offset(stream, &mmap_offset);
-               if (ret != 0) {
-                       PERROR("tracer ctl get_mmap_read_offset");
-                       ret = -EINVAL;
-                       goto end;
-               }
-               break;
-       default:
-               ERR("Unknown consumer_data type");
-               assert(0);
-       }
-
        /* Handle stream on the relayd if the output is on the network */
        if (relayd) {
                unsigned long netlen = len;
@@ -1803,7 +1773,7 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
         * This call guarantee that len or less is returned. It's impossible to
         * receive a ret value that is bigger than len.
         */
-       ret = lttng_write(outfd, mmap_base + mmap_offset, len);
+       ret = lttng_write(outfd, buffer, len);
        DBG("Consumer mmap write() ret %zd (len %lu)", ret, len);
        if (ret < 0 || ((size_t) ret != len)) {
                /*
index 23d4faf026d828a2cc3ff9dccc3a1757ce90db50..3ff9dbf9937219a18037c3cc4d00e7cc6c786f9a 100644 (file)
@@ -791,7 +791,9 @@ struct lttng_consumer_local_data *lttng_consumer_create(
 void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
 ssize_t lttng_consumer_on_read_subbuffer_mmap(
                struct lttng_consumer_local_data *ctx,
-               struct lttng_consumer_stream *stream, unsigned long len,
+               struct lttng_consumer_stream *stream,
+               const char *buffer,
+               unsigned long len,
                unsigned long padding,
                struct ctf_packet_index *index);
 ssize_t lttng_consumer_on_read_subbuffer_splice(
index 5075e05929238ade072391bf5367ae7f40c0433f..275c963df2305dee886327378f0a6a78e977e8db 100644 (file)
@@ -7,6 +7,7 @@
  *
  */
 
+#include <stdint.h>
 #define _LGPL_SOURCE
 #include <assert.h>
 #include <poll.h>
@@ -113,6 +114,25 @@ int lttng_kconsumer_get_consumed_snapshot(struct lttng_consumer_stream *stream,
        return ret;
 }
 
+static
+int get_current_subbuf_addr(struct lttng_consumer_stream *stream,
+               const char **addr)
+{
+       int ret;
+       unsigned long mmap_offset;
+       const char *mmap_base = stream->mmap_base;
+
+       ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
+       if (ret < 0) {
+               PERROR("Failed to get mmap read offset");
+               goto error;
+       }
+
+       *addr = mmap_base + mmap_offset;
+error:
+       return ret;
+}
+
 /*
  * Take a snapshot of all the stream of a channel
  * RCU read-side lock must be held across this function to ensure existence of
@@ -228,6 +248,7 @@ static int lttng_kconsumer_snapshot_channel(
                while ((long) (consumed_pos - produced_pos) < 0) {
                        ssize_t read_len;
                        unsigned long len, padded_len;
+                       const char *subbuf_addr;
 
                        health_code_update();
 
@@ -257,7 +278,13 @@ static int lttng_kconsumer_snapshot_channel(
                                goto error_put_subbuf;
                        }
 
-                       read_len = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len,
+                       ret = get_current_subbuf_addr(stream, &subbuf_addr);
+                       if (ret) {
+                               goto error_put_subbuf;
+                       }
+
+                       read_len = lttng_consumer_on_read_subbuffer_mmap(ctx,
+                                       stream, subbuf_addr, len,
                                        padded_len - len, NULL);
                        /*
                         * We write the padded len in local tracefiles but the data len
@@ -1691,6 +1718,9 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                }
                break;
        case CONSUMER_CHANNEL_MMAP:
+       {
+               const char *subbuf_addr;
+
                /* Get subbuffer size without padding */
                err = kernctl_get_subbuf_size(infd, &subbuf_size);
                if (err != 0) {
@@ -1710,13 +1740,20 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                        goto error;
                }
 
+               ret = get_current_subbuf_addr(stream, &subbuf_addr);
+               if (ret) {
+                       goto error_put_subbuf;
+               }
+
                /* Make sure the tracer is not gone mad on us! */
                assert(len >= subbuf_size);
 
                padding = len - subbuf_size;
 
                /* write the subbuffer to the tracefile */
-               ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size,
+               ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream,
+                               subbuf_addr,
+                               subbuf_size,
                                padding, &index);
                /*
                 * The mmap operation should write subbuf_size amount of data when
@@ -1736,11 +1773,12 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                        write_index = 0;
                }
                break;
+       }
        default:
                ERR("Unknown output method");
                ret = -EPERM;
        }
-
+error_put_subbuf:
        err = kernctl_put_next_subbuf(infd);
        if (err != 0) {
                if (err == -EFAULT) {
index 77a9670e7a2c1a5b9cf5b3d33c7f828b7d04046d..9055d0cf8baa82ef9a88257a3b002aa5823c1e5d 100644 (file)
@@ -7,6 +7,7 @@
  *
  */
 
+#include <stdint.h>
 #define _LGPL_SOURCE
 #include <assert.h>
 #include <lttng/ust-ctl.h>
@@ -1078,6 +1079,35 @@ error:
        return ret;
 }
 
+static
+int get_current_subbuf_addr(struct lttng_consumer_stream *stream,
+               const char **addr)
+{
+       int ret;
+       unsigned long mmap_offset;
+       const char *mmap_base;
+
+       mmap_base = ustctl_get_mmap_base(stream->ustream);
+       if (!mmap_base) {
+               ERR("Failed to get mmap base for stream `%s`",
+                               stream->name);
+               ret = -EPERM;
+               goto error;
+       }
+
+       ret = ustctl_get_mmap_read_offset(stream->ustream, &mmap_offset);
+       if (ret != 0) {
+               ERR("Failed to get mmap offset for stream `%s`", stream->name);
+               ret = -EINVAL;
+               goto error;
+       }
+
+       *addr = mmap_base + mmap_offset;
+error:
+       return ret;
+
+}
+
 /*
  * Take a snapshot of all the stream of a channel.
  * RCU read-side lock and the channel lock must be held by the caller.
@@ -1180,6 +1210,7 @@ static int snapshot_channel(struct lttng_consumer_channel *channel,
                while ((long) (consumed_pos - produced_pos) < 0) {
                        ssize_t read_len;
                        unsigned long len, padded_len;
+                       const char *subbuf_addr;
 
                        health_code_update();
 
@@ -1209,7 +1240,13 @@ static int snapshot_channel(struct lttng_consumer_channel *channel,
                                goto error_put_subbuf;
                        }
 
-                       read_len = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len,
+                       ret = get_current_subbuf_addr(stream, &subbuf_addr);
+                       if (ret) {
+                               goto error_put_subbuf;
+                       }
+
+                       read_len = lttng_consumer_on_read_subbuffer_mmap(ctx,
+                                       stream, subbuf_addr, len,
                                        padded_len - len, NULL);
                        if (use_relayd) {
                                if (read_len != len) {
@@ -2205,31 +2242,6 @@ end:
        return ret;
 }
 
-/*
- * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
- * compiled out, we isolate it in this library.
- */
-int lttng_ustctl_get_mmap_read_offset(struct lttng_consumer_stream *stream,
-               unsigned long *off)
-{
-       assert(stream);
-       assert(stream->ustream);
-
-       return ustctl_get_mmap_read_offset(stream->ustream, off);
-}
-
-/*
- * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
- * compiled out, we isolate it in this library.
- */
-void *lttng_ustctl_get_mmap_base(struct lttng_consumer_stream *stream)
-{
-       assert(stream);
-       assert(stream->ustream);
-
-       return ustctl_get_mmap_base(stream->ustream);
-}
-
 void lttng_ustctl_flush_buffer(struct lttng_consumer_stream *stream,
                int producer_active)
 {
@@ -2795,6 +2807,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        long ret = 0;
        struct ustctl_consumer_stream *ustream;
        struct ctf_packet_index index;
+       const char *subbuf_addr;
 
        assert(stream);
        assert(stream->ustream);
@@ -2904,11 +2917,19 @@ retry:
 
        padding = len - subbuf_size;
 
+       ret = get_current_subbuf_addr(stream, &subbuf_addr);
+       if (ret) {
+               write_index = 0;
+               goto error_put_subbuf;
+       }
+
        /* write the subbuffer to the tracefile */
-       ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding, &index);
+       ret = lttng_consumer_on_read_subbuffer_mmap(
+                       ctx, stream, subbuf_addr, subbuf_size, padding, &index);
        /*
-        * The mmap operation should write subbuf_size amount of data when network
-        * streaming or the full padding (len) size when we are _not_ streaming.
+        * The mmap operation should write subbuf_size amount of data when
+        * network streaming or the full padding (len) size when we are _not_
+        * streaming.
         */
        if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
                        (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
@@ -2925,6 +2946,7 @@ retry:
                                ret, len, subbuf_size);
                write_index = 0;
        }
+error_put_subbuf:
        err = ustctl_put_next_subbuf(ustream);
        assert(err == 0);
 
index 4068468962406b0f769157bc27c8d391c0478bba..b0a1df7f3b27d29993fc198c741b6a4b319e1256 100644 (file)
@@ -40,9 +40,6 @@ int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream);
 
 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream);
 
-int lttng_ustctl_get_mmap_read_offset(struct lttng_consumer_stream *stream,
-               unsigned long *off);
-void *lttng_ustctl_get_mmap_base(struct lttng_consumer_stream *stream);
 void lttng_ustctl_flush_buffer(struct lttng_consumer_stream *stream,
                int producer_active);
 int lttng_ustconsumer_get_stream_id(struct lttng_consumer_stream *stream,
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