libgit2 does not respect mmap window settings #1272
Description
i compiled with the following patch and observed that even though we asked libgit2 limit mmap to 64MB total, it mmaped()'ed over 200mb:
$ sudo -u git ./rdag-query . /tmp/dag.cache > log.txt
$ grep 222 log.txt |head -n1
mmaped (222510768)
diff --git a/src/mwindow.c b/src/mwindow.c
index 21f3c66..d1e6781 100644
--- a/src/mwindow.c
+++ b/src/mwindow.c
@@ -14,11 +14,12 @@
#define DEFAULT_WINDOW_SIZE \
(sizeof(void*) >= 8 \
- ? 1 * 1024 * 1024 * 1024 \
+ ? 32 * 1024 * 1024 \
: 32 * 1024 * 1024)
#define DEFAULT_MAPPED_LIMIT \
- ((1024 * 1024) * (sizeof(void*) >= 8 ? 8192ULL : 256UL))
+ ((1024 * 1024) * 64)
+//(sizeof(void*) >= 8 ? 8192ULL : 256UL))
/*
* These are the global options for mmmap limits.
diff --git a/src/unix/map.c b/src/unix/map.c
index ee7888c..a385dbb 100644
--- a/src/unix/map.c
+++ b/src/unix/map.c
@@ -12,6 +12,8 @@
#include <sys/mman.h>
#include <errno.h>
+static size_t mapped_bytes;
+
int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offset)
{
int mprot = 0;
@@ -35,6 +37,8 @@ int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, git_off_t offs
mflag = MAP_SHARED;
out->data = mmap(NULL, len, mprot, mflag, fd, offset);
+ mapped_bytes += len;
+ printf("mmaped (%zd)\n", mapped_bytes);
if (!out->data || out->data == MAP_FAILED) {
giterr_set(GITERR_OS, "Failed to mmap. Could not write data");
@@ -50,6 +54,8 @@ int p_munmap(git_map *map)
{
assert(map != NULL);
munmap(map->data, map->len);
+ mapped_bytes -= map->len;
+ printf("unmapped (%zd)\n", mapped_bytes);
return 0;
}//cc github/gitrpc#73