From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54478) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZtGmw-0004nc-Jp for qemu-devel@nongnu.org; Mon, 02 Nov 2015 10:12:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZtGms-0001gQ-Ih for qemu-devel@nongnu.org; Mon, 02 Nov 2015 10:12:50 -0500 Received: from relay.parallels.com ([195.214.232.42]:41464) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZtGms-0001gL-4M for qemu-devel@nongnu.org; Mon, 02 Nov 2015 10:12:46 -0500 Message-ID: <56377D56.6050301@virtuozzo.com> Date: Mon, 2 Nov 2015 18:12:22 +0300 From: Vladimir Sementsov-Ogievskiy MIME-Version: 1.0 References: <1446455617-129562-1-git-send-email-guangrong.xiao@linux.intel.com> <1446455617-129562-10-git-send-email-guangrong.xiao@linux.intel.com> In-Reply-To: <1446455617-129562-10-git-send-email-guangrong.xiao@linux.intel.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v7 09/35] exec: allow file_ram_alloc to work on file List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xiao Guangrong , pbonzini@redhat.com, imammedo@redhat.com Cc: ehabkost@redhat.com, kvm@vger.kernel.org, mst@redhat.com, gleb@kernel.org, mtosatti@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, dan.j.williams@intel.com, rth@twiddle.net On 02.11.2015 12:13, Xiao Guangrong wrote: > Currently, file_ram_alloc() only works on directory - it creates a file > under @path and do mmap on it > > This patch tries to allow it to work on file directly, if @path is a It isn't try to allow, it allows, as I understand) > directory it works as before, otherwise it treats @path as the target > file then directly allocate memory from it > > Signed-off-by: Xiao Guangrong > --- > exec.c | 80 ++++++++++++++++++++++++++++++++++++++++++------------------------ > 1 file changed, 51 insertions(+), 29 deletions(-) > > diff --git a/exec.c b/exec.c > index 9075f4d..db0fdaf 100644 > --- a/exec.c > +++ b/exec.c > @@ -1174,14 +1174,60 @@ void qemu_mutex_unlock_ramlist(void) > } > > #ifdef __linux__ > +static bool path_is_dir(const char *path) > +{ > + struct stat fs; > + > + return stat(path, &fs) == 0 && S_ISDIR(fs.st_mode); > +} > + > +static int open_ram_file_path(RAMBlock *block, const char *path, size_t size) > +{ > + char *filename; > + char *sanitized_name; > + char *c; > + int fd; > + > + if (!path_is_dir(path)) { > + int flags = (block->flags & RAM_SHARED) ? O_RDWR : O_RDONLY; > + > + flags |= O_EXCL; > + return open(path, flags); > + } > + > + /* Make name safe to use with mkstemp by replacing '/' with '_'. */ > + sanitized_name = g_strdup(memory_region_name(block->mr)); > + for (c = sanitized_name; *c != '\0'; c++) { > + if (*c == '/') { > + *c = '_'; > + } > + } > + filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path, > + sanitized_name); > + g_free(sanitized_name); one empty line will be very nice here, and it was in master branch > + fd = mkstemp(filename); > + if (fd >= 0) { > + unlink(filename); > + /* > + * ftruncate is not supported by hugetlbfs in older > + * hosts, so don't bother bailing out on errors. > + * If anything goes wrong with it under other filesystems, > + * mmap will fail. > + */ > + if (ftruncate(fd, size)) { > + perror("ftruncate"); > + } > + } > + g_free(filename); > + > + return fd; > +} > + > static void *file_ram_alloc(RAMBlock *block, > ram_addr_t memory, > const char *path, > Error **errp) > { > - char *filename; > - char *sanitized_name; > - char *c; > void *area; > int fd; > uint64_t pagesize; > @@ -1212,38 +1258,14 @@ static void *file_ram_alloc(RAMBlock *block, > goto error; > } > > - /* Make name safe to use with mkstemp by replacing '/' with '_'. */ > - sanitized_name = g_strdup(memory_region_name(block->mr)); > - for (c = sanitized_name; *c != '\0'; c++) { > - if (*c == '/') > - *c = '_'; > - } > - > - filename = g_strdup_printf("%s/qemu_back_mem.%s.XXXXXX", path, > - sanitized_name); > - g_free(sanitized_name); > + memory = ROUND_UP(memory, pagesize); > > - fd = mkstemp(filename); > + fd = open_ram_file_path(block, path, memory); > if (fd < 0) { > error_setg_errno(errp, errno, > "unable to create backing store for path %s", path); > - g_free(filename); > goto error; > } > - unlink(filename); > - g_free(filename); > - > - memory = ROUND_UP(memory, pagesize); > - > - /* > - * ftruncate is not supported by hugetlbfs in older > - * hosts, so don't bother bailing out on errors. > - * If anything goes wrong with it under other filesystems, > - * mmap will fail. > - */ > - if (ftruncate(fd, memory)) { > - perror("ftruncate"); > - } > > area = qemu_ram_mmap(fd, memory, pagesize, block->flags & RAM_SHARED); > if (area == MAP_FAILED) { Reviewed-by: Vladimir Sementsov-Ogievskiy -- Best regards, Vladimir * now, @virtuozzo.com instead of @parallels.com. Sorry for this inconvenience.