diff options
| -rw-r--r-- | exec.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/exec.c b/exec.c index 8ac556a2d4..24cdf64226 100644 --- a/exec.c +++ b/exec.c @@ -46,6 +46,11 @@ #include "sysemu/xen-mapcache.h" #include "trace-root.h" +#ifdef CONFIG_FALLOCATE_PUNCH_HOLE +#include <fcntl.h> +#include <linux/falloc.h> +#endif + #endif #include "exec/cpu-all.h" #include "qemu/rcu_queue.h" @@ -3326,12 +3331,23 @@ 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) - /* Note: We need the madvise MADV_DONTNEED behaviour of definitely - * freeing the page. - */ - ret = madvise(host_startaddr, length, MADV_DONTNEED); + /* Note: We need the madvise MADV_DONTNEED behaviour of definitely + * freeing the page. + */ + ret = madvise(host_startaddr, length, 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 " |