Bug 1401776 - Raise fd limit to 4096 on Unix. r=glandium,mcmanus

This is to accommodate non-networking fd usage (IPC transports, various
databases, .xpi files, etc.), so it's separate from Necko's existing
manipulation of the fd limit, which is tied into Necko's internal limits
on how many sockets it will try to poll at once.

Note that resource limits are inherited by child processes, so this needs
to be done only in the parent.

This patch also removes similar code used on Solaris and Mac OS X.  The
Mac case (bug 1036682) refers to fd use by graphics textures, which
shouldn't be consuming fds anymore (even transiently) as of bug 1161166.

MozReview-Commit-ID: 2uodrkW5sUn

--HG--
extra : rebase_source : 5306f4995000459b89bed048ecafba3c262bbbdf

Author: jld

gfx/thebes/gfxPlatformMac.cpp

@@ -81,18 +81,6 @@ gfxPlatformMac::gfxPlatformMac()
 
     InitBackendPrefs(GetBackendPrefs());
 
-    // XXX: Bug 1036682 - we run out of fds on Mac when using tiled layers because
-    // with 256x256 tiles we can easily hit the soft limit of 800 when using double
-    // buffered tiles in e10s, so let's bump the soft limit to the hard limit for the OS
-    // up to a new cap of OPEN_MAX.
-    struct rlimit limits;
-    if (getrlimit(RLIMIT_NOFILE, &limits) == 0) {
-        limits.rlim_cur = std::min(rlim_t(OPEN_MAX), limits.rlim_max);
-        if (setrlimit(RLIMIT_NOFILE, &limits) != 0) {
-            NS_WARNING("Unable to bump RLIMIT_NOFILE to the maximum number on this OS");
-        }
-    }
-
     MacIOSurfaceLib::LoadLibrary();
 }
 

toolkit/xre/nsAppRunner.cpp

@@ -153,9 +153,12 @@
 #include <locale.h>
 
 #ifdef XP_UNIX
+#include <errno.h>
+#include <pwd.h>
+#include <string.h>
+#include <sys/resource.h>
 #include <sys/stat.h>
 #include <unistd.h>
-#include <pwd.h>
 #endif
 
 #ifdef XP_WIN
@@ -3084,6 +3087,35 @@ CheckForUserMismatch()
 }
 #endif
 
+static void
+IncreaseDescriptorLimits()
+{
+#ifdef XP_UNIX
+  // Increase the fd limit to accomodate IPC resources like shared memory.
+  static const rlim_t kFDs = 4096;
+  struct rlimit rlim;
+
+  if (getrlimit(RLIMIT_NOFILE, &rlim) != 0) {
+    Output(false, "getrlimit: %s\n", strerror(errno));
+    return;
+  }
+  // Don't decrease the limit if it's already high enough, but don't
+  // try to go over the hard limit.  (RLIM_INFINITY isn't required to
+  // be the numerically largest rlim_t, so don't assume that.)
+  if (rlim.rlim_cur != RLIM_INFINITY && rlim.rlim_cur < kFDs &&
+      rlim.rlim_cur < rlim.rlim_max) {
+    if (rlim.rlim_max != RLIM_INFINITY && rlim.rlim_max < kFDs) {
+      rlim.rlim_cur = rlim.rlim_max;
+    } else {
+      rlim.rlim_cur = kFDs;
+    }
+    if (setrlimit(RLIMIT_NOFILE, &rlim) != 0) {
+      Output(false, "setrlimit: %s\n", strerror(errno));
+    }
+  }
+#endif
+}
+
 /*
  * XRE_mainInit - Initial setup and command line parameter processing.
  * Main() will exit early if either return value != 0 or if aExitFlag is
@@ -3154,6 +3186,8 @@ XREMain::XRE_mainInit(bool* aExitFlag)
     NS_BREAK();
 #endif
 
+  IncreaseDescriptorLimits();
+
 #ifdef USE_GLX_TEST
   // bug 639842 - it's very important to fire this process BEFORE we set up
   // error handling. indeed, this process is expected to be crashy, and we

toolkit/xre/nsSigHandlers.cpp

@@ -287,30 +287,6 @@ void InstallSignalHandlers(const char *aProgname)
   }
 #endif
 
-#if defined(SOLARIS)
-#define NOFILES 512
-
-    // Boost Solaris file descriptors
-    {
-	struct rlimit rl;
-
-	if (getrlimit(RLIMIT_NOFILE, &rl) == 0)
-
-	    if (rl.rlim_cur < NOFILES) {
-		rl.rlim_cur = NOFILES;
-
-		if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
-		    perror("setrlimit(RLIMIT_NOFILE)");
-		    fprintf(stderr, "Cannot exceed hard limit for open files");
-		}
-#if defined(DEBUG)
-	    	if (getrlimit(RLIMIT_NOFILE, &rl) == 0)
-		    printf("File descriptors set to %d\n", rl.rlim_cur);
-#endif //DEBUG
-	    }
-    }
-#endif //SOLARIS
-
 #if defined(MOZ_WIDGET_GTK) && (GLIB_MAJOR_VERSION > 2 || (GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION >= 6))
   const char *assertString = PR_GetEnv("XPCOM_DEBUG_BREAK");
   if (assertString &&