When the kernel supports MAP_HUGETLB use it for requesting
a huge page backed area instead of creating a file descriptor.
Signed-off-by: Eric B Munson <emun...@mgebm.net>
---
alloc.c | 41 +++++++++++++++++++++++++++++++++++------
1 files changed, 35 insertions(+), 6 deletions(-)
diff --git a/alloc.c b/alloc.c
index a7d37e5..bdee7b3 100644
--- a/alloc.c
+++ b/alloc.c
@@ -77,7 +77,7 @@ static void *fallback_base_pages(size_t len, ghp_t flags)
void *get_huge_pages(size_t len, ghp_t flags)
{
void *buf;
- int buf_fd;
+ int buf_fd = -1;
int saved_error;
int mmap_reserve = __hugetlb_opts.no_reserve ? MAP_NORESERVE : 0;
@@ -85,6 +85,27 @@ void *get_huge_pages(size_t len, ghp_t flags)
if (flags & GHR_MASK)
ERROR("Improper use of GHR_* in get_huge_pages()\n");
+#ifdef MAP_HUGETLB
+ if (__hugetlb_opts.map_hugetlb &&
+ gethugepagesize() == kernel_default_hugepage_size()) {
+ /* Because we can use MAP_HUGETLB, we simply mmap the region */
+ buf = mmap(NULL, len, PROT_READ|PROT_WRITE,
+ MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|mmap_reserve,
+ 0, 0);
+ } else {
+ /* Create a file descriptor for the new region */
+ buf_fd = hugetlbfs_unlinked_fd();
+ if (buf_fd < 0) {
+ WARNING("Couldn't open hugetlbfs file for %zd-sized
buffer\n",
+ len);
+ return NULL;
+ }
+
+ /* Map the requested region */
+ buf = mmap(NULL, len, PROT_READ|PROT_WRITE,
+ MAP_PRIVATE|mmap_reserve, buf_fd, 0);
+ }
+#else
/* Create a file descriptor for the new region */
buf_fd = hugetlbfs_unlinked_fd();
if (buf_fd < 0) {
@@ -95,20 +116,28 @@ void *get_huge_pages(size_t len, ghp_t flags)
/* Map the requested region */
buf = mmap(NULL, len, PROT_READ|PROT_WRITE,
- MAP_PRIVATE|mmap_reserve, buf_fd, 0);
+ MAP_PRIVATE|mmap_reserve, buf_fd, 0);
+#endif
+
if (buf == MAP_FAILED) {
- close(buf_fd);
+ if (buf_fd >= 0)
+ close(buf_fd);
WARNING("get_huge_pages: New region mapping failed (flags:
0x%lX): %s\n",
flags, strerror(errno));
return NULL;
}
- /* Fault the region to ensure accesses succeed */
+ /*
+ * Fault the region to ensure accesses succeed, buf_fd is passed
+ * regarless of how we mmap'd because if MAP_HUGETLB was used the value
+ * in buf_fd is ignored
+ */
if (hugetlbfs_prefault(buf_fd, buf, len) != 0) {
saved_error = errno;
munmap(buf, len);
- close(buf_fd);
+ if (buf_fd >= 0)
+ close(buf_fd);
WARNING("get_huge_pages: Prefaulting failed (flags: 0x%lX):
%s\n",
flags, strerror(saved_error));
@@ -116,7 +145,7 @@ void *get_huge_pages(size_t len, ghp_t flags)
}
/* Close the file so we do not have to track the descriptor */
- if (close(buf_fd) != 0) {
+ if (buf_fd >= 0 && close(buf_fd) != 0) {
WARNING("Failed to close new buffer fd: %s\n", strerror(errno));
munmap(buf, len);
return NULL;
--
1.7.1
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