daemon: Change default ‘timeout’ and ‘max-silent-time’ values.

Having a timeout seems generally preferable as it makes sure build slots
are not kept busy for no good reason (few package builds, if any, are
expected to exceed these values).

* nix/libstore/globals.cc (Settings::Settings): Change ‘maxSilentTime’
and ‘buildTimeout’.
* gnu/services/base.scm (<guix-configuration>)[max-silent-time]
[timeout]: Change default values.
* doc/guix.texi (Invoking guix-daemon, Base Services): Adjust
accordingly.

Change-Id: I25c50893f3f7fcca451b8f093d9d4d1a15fa58d8

doc/guix.texi

@@ -1799,7 +1799,7 @@ Setup}), or simply fail.
 When the build or substitution process remains silent for more than
 @var{seconds}, terminate it and report a build failure.
 
-The default value is @code{0}, which disables the timeout.
+The default value is @code{3600} (one hour).
 
 The value specified here can be overridden by clients (@pxref{Common
 Build Options, @option{--max-silent-time}}).
@@ -1808,7 +1808,7 @@ Build Options, @option{--max-silent-time}}).
 Likewise, when the build or substitution process lasts for more than
 @var{seconds}, terminate it and report a build failure.
 
-The default value is @code{0}, which disables the timeout.
+The default value is 24 hours.
 
 The value specified here can be overridden by clients (@pxref{Common
 Build Options, @option{--timeout}}).
@@ -19455,8 +19455,8 @@ few seconds when enough entropy is available and is only done once; you
 might want to turn it off for instance in a virtual machine that does
 not need it and where the extra boot time is a problem.
 
-@item @code{max-silent-time} (default: @code{0})
-@itemx @code{timeout} (default: @code{0})
+@item @code{max-silent-time} (default: @code{3600})
+@itemx @code{timeout} (default: @code{(* 3600 24)})
 The number of seconds of silence and the number of seconds of activity,
 respectively, after which a build process times out.  A value of zero
 disables the timeout.

gnu/services/base.scm

@@ -1798,9 +1798,9 @@ archive' public keys, with GUIX."
   (chroot-directories guix-configuration-chroot-directories ;list of file-like/strings
                       (default '()))
   (max-silent-time  guix-configuration-max-silent-time ;integer
-                    (default 0))
+                    (default 3600))
   (timeout          guix-configuration-timeout    ;integer
-                    (default 0))
+                    (default (* 3600 24)))
   (log-compression  guix-configuration-log-compression
                     (default 'gzip))
   (discover?        guix-configuration-discover?

nix/libstore/globals.cc

@@ -32,8 +32,8 @@ Settings::Settings()
     buildCores = 1;
     readOnlyMode = false;
     thisSystem = SYSTEM;
-    maxSilentTime = 0;
-    buildTimeout = 0;
+    maxSilentTime = 3600;
+    buildTimeout = 3600 * 24;
     useBuildHook = true;
     printBuildTrace = false;
     multiplexedBuildOutput = false;