lachrimae/lix
0
0
Fork 0
forked from lix-project/lix
Code Pull requests Activity

* Don't allocate a big initial GC address space on machines with

Browse source 
little RAM.  Even if the memory isn't actually used, it can cause
  problems with the overcommit heuristics in the kernel.  So use a VM
  space of 25% of RAM, up to 384 MB.
This commit is contained in:
Eelco Dolstra 2011-02-10 14:31:04 +00:00
parent 5a6b039802
commit 538b7caab0
2 changed files with 25 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
configure.ac
View file

@ -284,7 +284,7 @@ AC_CHECK_FUNCS([setresuid setreuid lchown])
# Nice to have, but not essential.
AC_CHECK_FUNCS([strsignal posix_fallocate nanosleep])
AC_CHECK_FUNCS([strsignal posix_fallocate nanosleep sysconf])
# This is needed if ATerm or bzip2 are static libraries,

35
src/libexpr/eval.cc
View file

@ -7,6 +7,7 @@
#include "globals.hh"
#include <cstring>
#include <unistd.h>
#if HAVE_BOEHMGC
@ -155,17 +156,29 @@ EvalState::EvalState()
#if HAVE_BOEHMGC
static bool gcInitialised = true;
if (gcInitialised) {
/* Set the initial heap size to something fairly big (384 MiB)
so that in most cases we don't need to garbage collect at
all. (Collection has a fairly significant overhead.) The
heap size can be overriden through libgc's
GC_INITIAL_HEAP_SIZE environment variable. We should
probably also provide a nix.conf setting for this. Note
that GC_expand_hp() causes a lot of virtual, but not
physical (resident) memory to be allocated. This might be
a problem on systems that don't overcommit. */
if (!getenv("GC_INITIAL_HEAP_SIZE"))
GC_expand_hp(384 * 1024 * 1024);
/* Set the initial heap size to something fairly big (25% of
physical RAM, up to a maximum of 384 MiB) so that in most
cases we don't need to garbage collect at all. (Collection
has a fairly significant overhead.) The heap size can be
overriden through libgc's GC_INITIAL_HEAP_SIZE environment
variable. We should probably also provide a nix.conf
setting for this. Note that GC_expand_hp() causes a lot of
virtual, but not physical (resident) memory to be
allocated. This might be a problem on systems that don't
overcommit. */
if (!getenv("GC_INITIAL_HEAP_SIZE")) {
size_t maxSize = 384 * 1024 * 1024;
size_t size = 32 * 1024 * 1024;
#if HAVE_SYSCONF && defined(_SC_PAGESIZE) && defined(_SC_PHYS_PAGES)
long pageSize = sysconf(_SC_PAGESIZE);
long pages = sysconf (_SC_PHYS_PAGES);
if (pageSize != -1 && size != -1)
size = (pageSize * pages) / 4; // 25% of RAM
if (size > maxSize) size = maxSize;
#endif
debug(format("setting initial heap size to %1% bytes") % size);
GC_expand_hp(size);
}
gcInitialised = true;
}
#endif