On 10/30/2015 10:04 PM, Vladimir Sementsov-Ogievskiy wrote:
On 30.10.2015 08:56, Xiao Guangrong wrote:Currently file_ram_alloc() is designed for hugetlbfs, however, the memory of nvdimm can come from either raw pmem device eg, /dev/pmem, or the file locates at DAX enabled filesystem So this patch let it work on any kind of path Signed-off-by: Xiao Guangrong <guangrong.x...@linux.intel.com> --- exec.c | 56 +++++++++++++++++--------------------------------------- 1 file changed, 17 insertions(+), 39 deletions(-) diff --git a/exec.c b/exec.c index 8af2570..3ca7e50 100644 --- a/exec.c +++ b/exec.c @@ -1174,32 +1174,6 @@ void qemu_mutex_unlock_ramlist(void) } #ifdef __linux__ - -#include <sys/vfs.h> - -#define HUGETLBFS_MAGIC 0x958458f6 - -static long gethugepagesize(const char *path, Error **errp) -{ - struct statfs fs; - int ret; - - do { - ret = statfs(path, &fs); - } while (ret != 0 && errno == EINTR); - - if (ret != 0) { - error_setg_errno(errp, errno, "failed to get page size of file %s", - path); - return 0; - } - - if (fs.f_type != HUGETLBFS_MAGIC) - fprintf(stderr, "Warning: path not on HugeTLBFS: %s\n", path); - - return fs.f_bsize; -} - static void *file_ram_alloc(RAMBlock *block, ram_addr_t memory, const char *path, @@ -1210,20 +1184,24 @@ static void *file_ram_alloc(RAMBlock *block, char *c; void *area; int fd; - uint64_t hpagesize; - Error *local_err = NULL; + uint64_t pagesize; - hpagesize = gethugepagesize(path, &local_err); - if (local_err) { - error_propagate(errp, local_err); + pagesize = qemu_file_get_page_size(path); + if (!pagesize) { + error_setg(errp, "can't get page size for %s", path); goto error; } - block->mr->align = hpagesize; - if (memory < hpagesize) { + if (pagesize == getpagesize()) { + fprintf(stderr, "Memory is not allocated from HugeTlbfs.\n"); + }It is strange to see this warning every time. Shouldn't the differentiation be done explicitly in command line? May be separate option mem-tlb, or separate flag tlbfs=on, or for new feature - new option mem-file, or prefixes for paths (tlbfs://, file://).. Or the other way to not mix things but split them.
This is just a reminder to users. Currently Qemu do not stop user to append a regular file for its backend memory, particularly, hugetlbfs is not the only way to use HugePage for the THP-enabled system. We can implement your idea as a independent patchset in the future.
