mmap-based fixed-size record double-buffered logger

Change-Id: I760b482b9de457bbb17de817db7079b57d3f5ec1
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 183 insertions, 0 deletions

diff --git a/src/vppinfra/maplog.c b/src/vppinfra/maplog.c
new file mode 100644
index 00000000000..3664364a9e1
--- /dev/null
+++ b/src/vppinfra/maplog.c
@@ -0,0 +1,183 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vppinfra/maplog.h>
+
+int
+clib_maplog_init (clib_maplog_main_t * mm, char *file_basename,
+		  u64 file_size_in_bytes, u32 record_size_in_bytes)
+{
+  int i, fd;
+  int rv = 0;
+  u8 zero = 0;
+  u32 record_size_in_cache_lines;
+  u64 file_size_in_records;
+
+  /* Already initialized? */
+  if (mm->flags & CLIB_MAPLOG_FLAG_INIT)
+    return (-2);
+
+  memset (mm, 0, sizeof (*mm));
+
+  record_size_in_cache_lines =
+    (record_size_in_bytes + CLIB_CACHE_LINE_BYTES -
+     1) / CLIB_CACHE_LINE_BYTES;
+
+  file_size_in_records = file_size_in_bytes
+    / (record_size_in_cache_lines * CLIB_CACHE_LINE_BYTES);
+
+  /* Round up file size in records to a power of 2, for speed... */
+  mm->log2_file_size_in_records = max_log2 (file_size_in_records);
+  file_size_in_records = 1ULL << (mm->log2_file_size_in_records);
+
+  file_size_in_bytes = file_size_in_records * record_size_in_cache_lines
+    * CLIB_CACHE_LINE_BYTES;
+
+  mm->file_basename = format (0, "%s", file_basename);
+  mm->file_size_in_records = file_size_in_records;
+  mm->flags |= CLIB_MAPLOG_FLAG_INIT;
+  mm->record_size_in_cachelines = record_size_in_cache_lines;
+
+  /* Map two files */
+  for (i = 0; i < 2; i++)
+    {
+      mm->filenames[i] = format (0, "%v_%d", mm->file_basename,
+				 mm->current_file_index++);
+
+      fd = open ((char *) mm->filenames[i], O_CREAT | O_RDWR | O_TRUNC, 0600);
+      if (fd < 0)
+	{
+	  rv = -3;
+	  goto fail;
+	}
+
+      if (lseek (fd, file_size_in_bytes - 1, SEEK_SET) == (off_t) - 1)
+	{
+	  rv = -4;
+	  goto fail;
+	}
+      if (write (fd, &zero, 1) != 1)
+	{
+	  rv = -5;
+	  goto fail;
+	}
+
+      mm->file_baseva[i] = mmap (0, file_size_in_bytes,
+				 PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+      if (mm->file_baseva[i] == (u8 *) MAP_FAILED)
+	{
+	  clib_unix_warning ("mmap");
+	  goto fail;
+	}
+      (void) close (fd);
+    }
+  return rv;
+
+fail:
+  if (fd)
+    (void) close (fd);
+
+  for (i = 0; i < 2; i++)
+    {
+      if (mm->file_baseva[i])
+	(void) munmap ((u8 *) mm->file_baseva[i], file_size_in_bytes);
+    }
+  return rv;
+}
+
+u8 *
+_clib_maplog_get_entry_slowpath (clib_maplog_main_t * mm, u64 my_record_index)
+{
+  int fd;
+  u8 *rv;
+  u8 zero = 0;
+  u32 unmap_index = (mm->current_file_index) & 1;
+  u64 file_size_in_bytes = mm->file_size_in_records
+    * mm->record_size_in_cachelines * CLIB_CACHE_LINE_BYTES;
+
+  (void) munmap ((u8 *) mm->file_baseva[unmap_index], file_size_in_bytes);
+  vec_reset_length (mm->filenames[unmap_index]);
+
+  mm->filenames[unmap_index] = format (mm->filenames[unmap_index],
+				       "%v_%d", mm->file_basename,
+				       mm->current_file_index++);
+
+  fd = open ((char *) mm->filenames[unmap_index],
+	     O_CREAT | O_RDWR | O_TRUNC, 0600);
+  /* $$$ this is not real error recovery... */
+  if (fd < 0)
+    {
+      clib_unix_warning ("creat");
+      abort ();
+    }
+
+  if (lseek (fd, file_size_in_bytes - 1, SEEK_SET) == (off_t) - 1)
+    {
+      clib_unix_warning ("lseek");
+      abort ();
+    }
+  if (write (fd, &zero, 1) != 1)
+    {
+      clib_unix_warning ("set-size write");
+      abort ();
+    }
+
+  mm->file_baseva[unmap_index] =
+    mmap (0, file_size_in_bytes, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+  if (mm->file_baseva[unmap_index] == (u8 *) MAP_FAILED)
+    {
+      clib_unix_warning ("mmap");
+      abort ();
+    }
+  (void) close (fd);
+
+  rv = (u8 *)
+    mm->file_baseva[(my_record_index >> mm->log2_file_size_in_records) & 1] +
+    (my_record_index & (mm->file_size_in_records - 1))
+    * mm->record_size_in_cachelines * CLIB_CACHE_LINE_BYTES;
+
+  return rv;
+}
+
+void
+clib_maplog_close (clib_maplog_main_t * mm)
+{
+  int i;
+  u64 file_size_in_bytes;
+
+  if (!(mm->flags & CLIB_MAPLOG_FLAG_INIT))
+    return;
+
+  file_size_in_bytes =
+    mm->file_size_in_records * mm->record_size_in_cachelines *
+    CLIB_CACHE_LINE_BYTES;
+
+  for (i = 0; i < 2; i++)
+    {
+      (void) munmap ((u8 *) mm->file_baseva[i], file_size_in_bytes);
+      vec_free (mm->filenames[i]);
+    }
+
+  vec_free (mm->file_basename);
+  memset (mm, 0, sizeof (*mm));
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */