From 5c6c3a6c54b23caa84fb4e046e85a461612279bb Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 20 Aug 2009 16:58:35 +0200 Subject: raw-posix: add Linux native AIO support Now that do have a nicer interface to work against we can add Linux native AIO support. It's an extremly thing layer just setting up an iocb for the io_submit system call in the submission path, and registering an eventfd with the qemu poll handler to do complete the iocbs directly from there. This started out based on Anthony's earlier AIO patch, but after estimated 42,000 rewrites and just as many build system changes there's not much left of it. To enable native kernel aio use the aio=native sub-command on the drive command line. I have also added an option to qemu-io to test the aio support without needing a guest. Signed-off-by: Christoph Hellwig Signed-off-by: Anthony Liguori --- vl.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'vl.c') diff --git a/vl.c b/vl.c index 9b2bf00a72..1085794190 100644 --- a/vl.c +++ b/vl.c @@ -1916,6 +1916,7 @@ DriveInfo *drive_init(QemuOpts *opts, void *opaque, int max_devs; int index; int cache; + int aio = 0; int bdrv_flags, onerror; const char *devaddr; DriveInfo *dinfo; @@ -2049,6 +2050,19 @@ DriveInfo *drive_init(QemuOpts *opts, void *opaque, } } +#ifdef CONFIG_LINUX_AIO + if ((buf = qemu_opt_get(opts, "aio")) != NULL) { + if (!strcmp(buf, "threads")) + aio = 0; + else if (!strcmp(buf, "native")) + aio = 1; + else { + fprintf(stderr, "qemu: invalid aio option\n"); + return NULL; + } + } +#endif + if ((buf = qemu_opt_get(opts, "format")) != NULL) { if (strcmp(buf, "?") == 0) { fprintf(stderr, "qemu: Supported formats:"); @@ -2218,11 +2232,19 @@ DriveInfo *drive_init(QemuOpts *opts, void *opaque, bdrv_flags |= BDRV_O_NOCACHE; else if (cache == 2) /* write-back */ bdrv_flags |= BDRV_O_CACHE_WB; + + if (aio == 1) { + bdrv_flags |= BDRV_O_NATIVE_AIO; + } else { + bdrv_flags &= ~BDRV_O_NATIVE_AIO; + } + if (bdrv_open2(dinfo->bdrv, file, bdrv_flags, drv) < 0) { fprintf(stderr, "qemu: could not open disk image %s\n", file); return NULL; } + if (bdrv_key_required(dinfo->bdrv)) autostart = 0; *fatal_error = 0; -- cgit v1.2.1