Preload is only useful when linking against an non-relinked binary
and only then when we are only attempting to back the heap. No other
combination can usefully use preload. Using preload with a relinked
binary is safe as long as you are only requesting backing of the heap.
Therefore unconditionally enable preload iff we are requesting only --heap.
As a failsafe allow the user to disable preload.
Note that we make use of the fact that for a standard install the
libraries will appear on the default libarary path, and that the loader
will correctly pick an appropriate library 32/64 bit based on the binary.
Signed-off-by: Andy Whitcroft <[EMAIL PROTECTED]>
Acked-by: Mel Gorman <[EMAIL PROTECTED]>
Acked-by: Adam Litke <[EMAIL PROTECTED]>
Acked-by: Eric B Munson <[EMAIL PROTECTED]>
---
hugectl.c | 25 +++++++++++++++++++++++++
1 files changed, 25 insertions(+), 0 deletions(-)
diff --git a/hugectl.c b/hugectl.c
index 79e934c..755d3b6 100644
--- a/hugectl.c
+++ b/hugectl.c
@@ -64,6 +64,8 @@ void print_usage()
OPTION("--bss", "Requests remapping of the program bss");
OPTION("--heap", "Requests remapping of the program heap");
CONT("(malloc space)");
+
+ OPTION("--no-preload", "Disable preloading the libhugetlbfs library");
}
int verbose_level = VERBOSITY_DEFAULT;
@@ -91,6 +93,9 @@ void setup_environment(char *var, char *val)
* getopts return values for options which are long only.
*/
#define MAP_BASE 0x1000
+#define LONG_BASE 0x2000
+
+#define LONG_NO_PRELOAD (LONG_BASE | 'p')
/*
* Mapping selectors, one bit per remappable/backable area as requested
@@ -135,14 +140,26 @@ void setup_mappings(int which)
setup_environment("HUGETLB_MORECORE", "yes");
}
+void ldpreload(int which)
+{
+ if (which == MAP_HEAP) {
+ setup_environment("LD_PRELOAD", "libhugetlbfs.so");
+ WARNING("LD_PRELOAD in use for lone --heap\n");
+ } else {
+ DEBUG("LD_PRELOAD not appropriate for this map combination\n");
+ }
+}
+
int main(int argc, char** argv)
{
int opt_mappings = 0;
+ int opt_preload = 1;
char opts[] = "+h";
int ret = 0, index = 0;
struct option long_opts[] = {
{"help", no_argument, NULL, 'h'},
+ {"no-preload", no_argument, NULL, LONG_NO_PRELOAD},
{"disable", no_argument, NULL, MAP_BASE|MAP_DISABLE},
{"text", no_argument, NULL, MAP_BASE|MAP_TEXT},
@@ -170,6 +187,11 @@ int main(int argc, char** argv)
print_usage();
exit(EXIT_SUCCESS);
+ case LONG_NO_PRELOAD:
+ opt_preload = 0;
+ DEBUG("LD_PRELOAD disabled\n");
+ break;
+
default:
WARNING("unparsed option %08x\n", ret);
ret = -1;
@@ -187,6 +209,9 @@ int main(int argc, char** argv)
if (opt_mappings)
setup_mappings(opt_mappings);
+ if (opt_preload)
+ ldpreload(opt_mappings);
+
execvp(argv[index], &argv[index]);
ERROR("exec failed: %s\n", strerror(errno));
exit(EXIT_FAILURE);
--
1.5.6.GIT
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