processes plugin: Add support for Linux Delay Accounting.

Makefile.am

@@ -1421,14 +1421,28 @@ python_la_CPPFLAGS = $(AM_CPPFLAGS) $(LIBPYTHON_CPPFLAGS)
 python_la_LDFLAGS = $(PLUGIN_LDFLAGS) $(LIBPYTHON_LDFLAGS)
 endif
 
+if HAVE_LIBMNL
+noinst_LTLIBRARIES += libtaskstats.la
+libtaskstats_la_SOURCES = \
+	src/utils_taskstats.c \
+	src/utils_taskstats.h
+libtaskstats_la_CFLAGS = $(AM_CFLAGS) $(BUILD_WITH_LIBMNL_CFLAGS)
+libtaskstats_la_LIBADD = $(BUILD_WITH_LIBMNL_LIBS)
+endif
+
 if BUILD_PLUGIN_PROCESSES
 pkglib_LTLIBRARIES += processes.la
 processes_la_SOURCES = src/processes.c
+processes_la_CPPFLAGS = $(AM_CPPFLAGS)
 processes_la_LDFLAGS = $(PLUGIN_LDFLAGS)
 processes_la_LIBADD =
 if BUILD_WITH_LIBKVM_GETPROCS
 processes_la_LIBADD += -lkvm
 endif
+if HAVE_LIBMNL
+processes_la_CPPFLAGS += -DHAVE_LIBTASKSTATS=1
+processes_la_LIBADD += libtaskstats.la
+endif
 endif
 
 if BUILD_PLUGIN_PROTOCOLS

configure.ac

@@ -3668,6 +3668,7 @@ if test "x$with_libmnl" = "xyes"; then
 fi
 AC_SUBST([BUILD_WITH_LIBMNL_CFLAGS])
 AC_SUBST([BUILD_WITH_LIBMNL_LIBS])
+AM_CONDITIONAL([HAVE_LIBMNL], [test "x$with_libmnl" = "xyes"])
 # }}}
 
 # --with-libnetapp {{{

contrib/systemd.collectd.service

@@ -22,6 +22,7 @@ ProtectHome=true
 #   intel_pmu       CAP_SYS_ADMIN
 #   iptables        CAP_NET_ADMIN
 #   ping            CAP_NET_RAW
+#   processes       CAP_NET_ADMIN  (CollectDelayAccounting only)
 #   smart           CAP_SYS_RAWIO
 #   turbostat       CAP_SYS_RAWIO
 #

src/collectd.conf.in

@@ -1200,11 +1200,13 @@
 #	CollectFileDescriptor true
 #	CollectContextSwitch true
 #	CollectMemoryMaps true
+#	CollectDelayAccounting false
 #	Process "name"
 #	ProcessMatch "name" "regex"
 #	<Process "collectd">
 #		CollectFileDescriptor false
 #		CollectContextSwitch false
+#		CollectDelayAccounting true
 #	</Process>
 #	<ProcessMatch "name" "regex">
 #		CollectFileDescriptor false

src/collectd.conf.pod

@@ -6842,22 +6842,25 @@ The statistics collected for matched processes are:
  - number of memory mapped files (under Linux)
  - io data (where available)
  - context switches (under Linux)
- - minor and major pagefaults.
+ - minor and major pagefaults
+ - Delay Accounting information (Linux only, requires libmnl)
 
 B<Synopsis:>
 
  <Plugin processes>
-   CollectFileDescriptor true
-   CollectContextSwitch true
+   CollectFileDescriptor  true
+   CollectContextSwitch   true
+   CollectDelayAccounting false
    Process "name"
    ProcessMatch "name" "regex"
    <Process "collectd">
-     CollectFileDescriptor false
-     CollectContextSwitch false
+     CollectFileDescriptor  false
+     CollectContextSwitch   false
+     CollectDelayAccounting true
    </Process>
    <ProcessMatch "name" "regex">
      CollectFileDescriptor false
-     CollectContextSwitch true
+     CollectContextSwitch  true
    </Process>
  </Plugin>
 
@@ -6883,6 +6886,18 @@ I<name> must not contain slashes.
 Collect the number of context switches for matched processes.
 Disabled by default.
 
+=item B<CollectDelayAccounting> I<Boolean>
+
+If enabled, collect Linux Delay Accounding information for matching processes.
+Delay Accounting provides the time processes wait for the CPU to become
+available, for I/O operations to finish, for pages to be swapped in and for
+freed pages to be reclaimed. The metrics are reported as "seconds per second"
+using the C<delay_rate> type, e.g. C<delay_rate-delay-cpu>.
+Disabled by default.
+
+This option is only available on Linux, requires the C<libmnl> library and
+requires the C<CAP_NET_ADMIN> capability at runtime.
+
 =item B<CollectFileDescriptor> I<Boolean>
 
 Collect number of file descriptors of matched processes.
@@ -6896,9 +6911,12 @@ the Linux kernel.
 
 =back
 
-Options B<CollectContextSwitch> and B<CollectFileDescriptor> may be used inside
-B<Process> and B<ProcessMatch> blocks - then they affect corresponding match
-only. Otherwise they set the default value for subsequent matches.
+The B<CollectContextSwitch>, B<CollectDelayAccounting>,
+B<CollectFileDescriptor> and B<CollectMemoryMaps> options may be used inside
+B<Process> and B<ProcessMatch> blocks. When used there, these options affect
+reporting the corresponding processes only. Outside of B<Process> and
+B<ProcessMatch> blocks these options set the default value for subsequent
+matches.
 
 =head2 Plugin C<protocols>