From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
Unfortunately madvise DONTNEED doesn't work on hugepagetlb
so use fallocate(FALLOC_FL_PUNCH_HOLE)
qemu_fd_getpagesize only sets the page based off a file
if the file is from hugetlbfs.
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
exec.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/exec.c b/exec.c
index e040cdf..c25f6b3 100644
--- a/exec.c
+++ b/exec.c
@@ -3324,9 +3324,20 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t
start, size_t length)
errno = ENOTSUP; /* If we are missing MADVISE etc */
+ if (rb->page_size == qemu_host_page_size) {
#if defined(CONFIG_MADVISE)
- ret = qemu_madvise(host_startaddr, length, QEMU_MADV_DONTNEED);
+ ret = qemu_madvise(host_startaddr, length, QEMU_MADV_DONTNEED);
#endif
+ } else {
+ /* Huge page case - unfortunately it can't do DONTNEED, but
+ * it can do the equivalent by FALLOC_FL_PUNCH_HOLE in the
+ * huge page file.
+ */
+#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
+ ret = fallocate(rb->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ start, length);
+#endif
+ }
if (ret) {
ret = -errno;
error_report("ram_block_discard_range: Failed to discard range "
--
2.9.3
