On Thu, Jan 9, 2014 at 5:01 PM, Michael S. Tsirkin <m...@redhat.com> wrote:
> On Thu, Jan 09, 2014 at 03:59:55PM +0100, Antonios Motakis wrote:
> > Extend -mem-path with additional properties:
> >
> > - prealloc=on|off - default off, same as -mem-prealloc
> > - share=on|off - default off, memory is mmapped with MAP_SHARED flag
> > - unlink=on|off - default on, inlink the file after openinng it
>
> typos
>
Ack.
>
> >
> > Signed-off-by: Antonios Motakis <a.mota...@virtualopensystems.com>
> > Signed-off-by: Nikolay Nikolaev <n.nikol...@virtualopensystems.com>
> > ---
> > exec.c | 57
> +++++++++++++++++++++++++++++++++++++++++---------
> > include/exec/cpu-all.h | 3 ---
> > qemu-options.hx | 10 +++++++--
> > vl.c | 41 +++++++++++++++++++++++++++++++-----
> > 4 files changed, 91 insertions(+), 20 deletions(-)
> >
> > diff --git a/exec.c b/exec.c
> > index 7e49e8e..30f4019 100644
> > --- a/exec.c
> > +++ b/exec.c
> > @@ -957,6 +957,7 @@ void qemu_mutex_unlock_ramlist(void)
> > #include <sys/vfs.h>
> >
> > #define HUGETLBFS_MAGIC 0x958458f6
> > +#define MIN_HUGE_PAGE_SIZE (2*1024*1024)
> >
> > static long gethugepagesize(const char *path)
> > {
> > @@ -972,8 +973,9 @@ static long gethugepagesize(const char *path)
> > return 0;
> > }
> >
> > - if (fs.f_type != HUGETLBFS_MAGIC)
> > - fprintf(stderr, "Warning: path not on HugeTLBFS: %s\n", path);
> > + if (fs.f_type != HUGETLBFS_MAGIC) {
> > + return 0;
> > + }
> >
> > return fs.f_bsize;
> > }
> > @@ -994,11 +996,14 @@ static void *file_ram_alloc(RAMBlock *block,
> > char *c;
> > void *area;
> > int fd;
> > + int flags;
> > unsigned long hpagesize;
> > + QemuOpts *opts;
> > + unsigned int mem_prealloc = 0, mem_share = 0, mem_unlink = 1;
> >
> > hpagesize = gethugepagesize(path);
> > if (!hpagesize) {
> > - return NULL;
> > + hpagesize = MIN_HUGE_PAGE_SIZE;
> > }
> >
> > if (memory < hpagesize) {
> > @@ -1010,6 +1015,14 @@ static void *file_ram_alloc(RAMBlock *block,
> > return NULL;
> > }
> >
> > + /* Fill config options */
> > + opts = qemu_opts_find(qemu_find_opts("mem-path"), NULL);
> > + if (opts) {
> > + mem_prealloc = qemu_opt_get_bool(opts, "prealloc", 0);
> > + mem_share = qemu_opt_get_bool(opts, "share", 0);
> > + mem_unlink = qemu_opt_get_bool(opts, "unlink", 1);
> > + }
> > +
> > /* Make name safe to use with mkstemp by replacing '/' with '_'. */
> > sanitized_name = g_strdup(block->mr->name);
> > for (c = sanitized_name; *c != '\0'; c++) {
> > @@ -1017,20 +1030,28 @@ static void *file_ram_alloc(RAMBlock *block,
> > *c = '_';
> > }
> >
> > - filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path,
> > - sanitized_name);
> > + filename = g_strdup_printf("%s/qemu_back_mem.%s%s", path,
> sanitized_name,
> > + (mem_unlink) ? ".XXXXXX" : "");
> > g_free(sanitized_name);
> >
> > - fd = mkstemp(filename);
> > + if (mem_unlink) {
> > + fd = mkstemp(filename);
> > + } else {
> > + fd = open(filename, O_CREAT | O_RDWR | O_EXCL,
> > + S_IRWXU | S_IRWXG | S_IRWXO);
> > + }
> > if (fd < 0) {
> > - perror("unable to create backing store for hugepages");
> > + perror("unable to create guest RAM backing store");
> > g_free(filename);
> > return NULL;
> > }
> > - unlink(filename);
> > +
> > + if (mem_unlink) {
> > + unlink(filename);
> > + }
>
> If we don't unlink, what will?
>
The option to not unlink the file was added based on feedback on these
mailing lists:
http://lists.nongnu.org/archive/html/qemu-devel/2013-12/msg02769.html
>From our side we don't strictly need it, and we can remove it if it is
preferred that way.
>
> > g_free(filename);
> >
> > - memory = (memory+hpagesize-1) & ~(hpagesize-1);
> > + memory = (memory + hpagesize - 1) & ~(hpagesize - 1);
> >
> > /*
> > * ftruncate is not supported by hugetlbfs in older
> > @@ -1041,7 +1062,8 @@ static void *file_ram_alloc(RAMBlock *block,
> > if (ftruncate(fd, memory))
> > perror("ftruncate");
> >
> > - area = mmap(0, memory, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
> > + flags = mem_share ? MAP_SHARED : MAP_PRIVATE;
> > + area = mmap(0, memory, PROT_READ | PROT_WRITE, flags, fd, 0);
> > if (area == MAP_FAILED) {
> > perror("file_ram_alloc: can't mmap RAM pages");
> > close(fd);
> > @@ -1211,11 +1233,18 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t
> size, void *host,
> > MemoryRegion *mr)
> > {
> > RAMBlock *block, *new_block;
> > + QemuOpts *opts;
> > + const char *mem_path = 0;
> >
> > size = TARGET_PAGE_ALIGN(size);
> > new_block = g_malloc0(sizeof(*new_block));
> > new_block->fd = -1;
> >
> > + opts = qemu_opts_find(qemu_find_opts("mem-path"), NULL);
> > + if (opts) {
> > + mem_path = qemu_opt_get(opts, "path");
> > + }
> > +
> > /* This assumes the iothread lock is taken here too. */
> > qemu_mutex_lock_ramlist();
> > new_block->mr = mr;
> > @@ -1348,6 +1377,14 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t
> length)
> > ram_addr_t offset;
> > int flags;
> > void *area, *vaddr;
> > + QemuOpts *opts;
> > + unsigned int mem_prealloc = 0;
> > +
> > + /* Fill config options */
> > + opts = qemu_opts_find(qemu_find_opts("mem-path"), NULL);
> > + if (opts) {
> > + mem_prealloc = qemu_opt_get_bool(opts, "prealloc", 0);
> > + }
> >
> > QTAILQ_FOREACH(block, &ram_list.blocks, next) {
> > offset = addr - block->offset;
> > diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
> > index b6998f0..4f8e989 100644
> > --- a/include/exec/cpu-all.h
> > +++ b/include/exec/cpu-all.h
> > @@ -467,9 +467,6 @@ typedef struct RAMList {
> > } RAMList;
> > extern RAMList ram_list;
> >
> > -extern const char *mem_path;
> > -extern int mem_prealloc;
> > -
> > /* Flags stored in the low bits of the TLB virtual address. These are
> > defined so that fast path ram access is all zeros. */
> > /* Zero if TLB entry is valid. */
> > diff --git a/qemu-options.hx b/qemu-options.hx
> > index bcfe9ea..0d35c9c 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -221,9 +221,15 @@ gigabytes respectively.
> > ETEXI
> >
> > DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath,
> > - "-mem-path FILE provide backing storage for guest RAM\n",
> QEMU_ARCH_ALL)
> > + "-mem-path
> [path=]path[,prealloc=on|off][,share=on|off][,unlink=on|off]\n"
> > + " provide backing storage for guest RAM\n"
> > + " path= a directory path for the backing store\n"
> > + " prealloc= preallocate guest memory [default
> disabled]\n"
> > + " share= enable mmap share flag [default disabled]\n"
> > + " unlink= enable unlinking the guest RAM files
> [default enabled]\n",
> > + QEMU_ARCH_ALL)
> > STEXI
> > -@item -mem-path @var{path}
> > +@item -mem-path
> [path=]@var{path}[,prealloc=on|off][,share=on|off][,unlink=on|off]
> > @findex -mem-path
> > Allocate guest RAM from a temporarily created file in @var{path}.
> > ETEXI
> > diff --git a/vl.c b/vl.c
> > index 7511e70..4a52e0d 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -187,8 +187,6 @@ DisplayType display_type = DT_DEFAULT;
> > static int display_remote;
> > const char* keyboard_layout = NULL;
> > ram_addr_t ram_size;
> > -const char *mem_path = NULL;
> > -int mem_prealloc = 0; /* force preallocation of physical target memory
> */
> > int nb_nics;
> > NICInfo nd_table[MAX_NICS];
> > int autostart;
> > @@ -531,6 +529,31 @@ static QemuOptsList qemu_msg_opts = {
> > },
> > };
> >
> > +static QemuOptsList qemu_mem_path_opts = {
> > + .name = "mem-path",
> > + .implied_opt_name = "path",
> > + .head = QTAILQ_HEAD_INITIALIZER(qemu_mem_path_opts.head),
> > + .desc = {
> > + {
> > + .name = "path",
> > + .type = QEMU_OPT_STRING,
> > + },
> > + {
> > + .name = "prealloc",
> > + .type = QEMU_OPT_BOOL,
> > + },
> > + {
> > + .name = "share",
> > + .type = QEMU_OPT_BOOL,
> > + },
> > + {
> > + .name = "unlink",
> > + .type = QEMU_OPT_BOOL,
> > + },
> > + { /* end of list */ }
> > + },
> > +};
> > +
> > /**
> > * Get machine options
> > *
> > @@ -2892,6 +2915,7 @@ int main(int argc, char **argv, char **envp)
> > qemu_add_opts(&qemu_tpmdev_opts);
> > qemu_add_opts(&qemu_realtime_opts);
> > qemu_add_opts(&qemu_msg_opts);
> > + qemu_add_opts(&qemu_mem_path_opts);
> >
> > runstate_init();
> >
> > @@ -3209,11 +3233,18 @@ int main(int argc, char **argv, char **envp)
> > break;
> > #endif
> > case QEMU_OPTION_mempath:
> > - mem_path = optarg;
> > + if (!qemu_opts_parse(qemu_find_opts("mem-path"),
> optarg, 1)) {
> > + exit(1);
> > + }
> > break;
> > - case QEMU_OPTION_mem_prealloc:
> > - mem_prealloc = 1;
> > + case QEMU_OPTION_mem_prealloc: {
> > + QemuOpts *mem_opts =
> qemu_opts_find(qemu_find_opts("mem-path"),
> > + NULL);
> > + if (mem_opts) {
> > + qemu_opt_set(mem_opts, "prealloc", "on");
> > + }
> > break;
> > + }
> > case QEMU_OPTION_d:
> > log_mask = optarg;
> > break;
> > --
> > 1.8.3.2
> >
>
