graal-jvmci-8: src/os/linux/vm/os

comparison src/os/linux/vm/os_linux.cpp @ 24179:75021e6fe108

8170307: Stack size option -Xss is ignored Reviewed-by: dcubed, sspitsyn, gtriantafill

author	dholmes
date	Tue, 20 Dec 2016 16:06:10 -0500
parents	e21dd2c95cf0
children	719853999215

comparison

equal deleted inserted replaced

-:ab892d05b029
+:75021e6fe108
 return false;
 }
 // Locate initial thread stack. This special handling of initial thread stack
 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
-// bogus value for initial thread.
+// bogus value for the primordial process thread. While the launcher has created
+// the VM in a new thread since JDK 6, we still have to allow for the use of the
+// JNI invocation API from a primordial thread.
 void os::Linux::capture_initial_stack(size_t max_size) {
-// stack size is the easy part, get it from RLIMIT_STACK
-size_t stack_size;
+// max_size is either 0 (which means accept OS default for thread stacks) or
+// a user-specified value known to be at least the minimum needed. If we
+// are actually on the primordial thread we can make it appear that we have a
+// smaller max_size stack by inserting the guard pages at that location. But we
+// cannot do anything to emulate a larger stack than what has been provided by
+// the OS or threading library. In fact if we try to use a stack greater than
+// what is set by rlimit then we will crash the hosting process.
+// Maximum stack size is the easy part, get it from RLIMIT_STACK.
+// If this is "unlimited" then it will be a huge value.
 struct rlimit rlim;
 getrlimit(RLIMIT_STACK, &rlim);
-stack_size = rlim.rlim_cur;
+size_t stack_size = rlim.rlim_cur;
 // 6308388: a bug in ld.so will relocate its own .data section to the
 //   lower end of primordial stack; reduce ulimit -s value a little bit
 //   so we won't install guard page on ld.so's data section.
 stack_size -= 2 * page_size();
-// 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
-//   7.1, in both cases we will get 2G in return value.
-// 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
-//   SuSE 7.2, Debian) can not handle alternate signal stack correctly
-//   for initial thread if its stack size exceeds 6M. Cap it at 2M,
-//   in case other parts in glibc still assumes 2M max stack size.
-// FIXME: alt signal stack is gone, maybe we can relax this constraint?
-// Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
-if (stack_size > 2 * K * K IA64_ONLY(*2))
-stack_size = 2 * K * K IA64_ONLY(*2);
 // Try to figure out where the stack base (top) is. This is harder.
 //
 // When an application is started, glibc saves the initial stack pointer in
 // a global variable "__libc_stack_end", which is then used by system
 // libraries. __libc_stack_end should be pretty close to stack top. The
 }
 // stack_top could be partially down the page so align it
 stack_top = align_size_up(stack_top, page_size());
-if (max_size && stack_size > max_size) {
+// Allowed stack value is minimum of max_size and what we derived from rlimit
-_initial_thread_stack_size = max_size;
+if (max_size > 0) {
+_initial_thread_stack_size = MIN2(max_size, stack_size);
 } else {
-_initial_thread_stack_size = stack_size;
+// Accept the rlimit max, but if stack is unlimited then it will be huge, so
+// clamp it at 8MB as we do on Solaris
+_initial_thread_stack_size = MIN2(stack_size, 8*M);
 }
 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
+assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
 }
 ////////////////////////////////////////////////////////////////////////////////
 // time support

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comparison src/os/linux/vm/os_linux.cpp @ 24179:75021e6fe108