Re: [libvirt] [PATCH] Support configuration of huge pages in guests

* configure.in: Add check for mntent.h * qemud/libvirtd_qemu.aug, qemud/test_libvirtd_qemu.aug, src/qemu.conf Add 'hugetlbfs_mount' config parameter * src/qemu_conf.c, src/qemu_conf.h: Check for -mem-path flag in QEMU, and pass it when hugepages are requested. Load hugetlbfs_mount config parameter, search for mount if not given. * src/qemu_driver.c: Free hugetlbfs_mount/path parameter in driver shutdown. Create directory for QEMU hugepage usage, chowning if required. * docs/formatdomain.html.in: Document memoryBacking/hugepages elements * docs/schemas/domain.rng: Add memoryBacking/hugepages elements to schema * src/util.c, src/util.h, src/libvirt_private.syms: Add virFileFindMountPoint helper API * tests/qemuhelptest.c: Add -mem-path constants * tests/qemuxml2argvtest.c, tests/qemuxml2xmltest.c: Add tests for hugepage handling * tests/qemuxml2argvdata/qemuxml2argv-hugepages.xml, tests/qemuxml2argvdata/qemuxml2argv-hugepages.args: Data files for hugepage tests --- configure.in | 2 +- docs/formatdomain.html | 8 +++- docs/formatdomain.html.in | 8 +++ docs/schemas/domain.rng | 9 ++++ qemud/libvirtd_qemu.aug | 1 + qemud/test_libvirtd_qemu.aug | 4 ++ src/domain_conf.c | 10 ++++- src/domain_conf.h | 1 + src/libvirt_private.syms | 1 + src/qemu.conf | 13 +++++ src/qemu_conf.c | 49 ++++++++++++++++++++ src/qemu_conf.h | 3 + src/qemu_driver.c | 34 ++++++++++++++ src/util.c | 37 ++++++++++++++- src/util.h | 4 ++ tests/qemuhelptest.c | 6 ++- tests/qemuxml2argvdata/qemuxml2argv-hugepages.args | 1 + tests/qemuxml2argvdata/qemuxml2argv-hugepages.xml | 25 ++++++++++ tests/qemuxml2argvtest.c | 7 ++- tests/qemuxml2xmltest.c | 1 + 20 files changed, 217 insertions(+), 7 deletions(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-hugepages.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-hugepages.xml

diff --git a/src/qemu_conf.c b/src/qemu_conf.c index 22f5edd..4935e2f 100644 --- a/src/qemu_conf.c +++ b/src/qemu_conf.c @@ -35,6 +35,7 @@ #include <sys/wait.h> #include <arpa/inet.h> #include <sys/utsname.h> +#include <mntent.h> #include "c-ctype.h" #include "virterror_internal.h" @@ -87,6 +88,7 @@ VIR_ENUM_IMPL(qemuVideo, VIR_DOMAIN_VIDEO_TYPE_LAST, NULL, /* no arg needed for xen */ NULL /* don't support vbox */); +#define PROC_MOUNT_BUF_LEN 255 int qemudLoadDriverConfig(struct qemud_driver *driver, const char *filename) { @@ -106,6 +108,19 @@ int qemudLoadDriverConfig(struct qemud_driver *driver, return -1; } + /* For privilege driver, try and find hugepage mount automatically.

+ * Non-privileged driver requires admin to create a dir for the + * user, chown it, and then let user configure it manually */ + if (driver->privileged && + !(driver->hugetlbfs_mount = virFileFindMountPoint("hugetlbfs"))) { + if (errno != ENOENT) { + virReportSystemError(NULL, errno, "%s", + _("unable to find hugetlbfs mountpoint")); + return -1; + } + } + + /* Just check the file is readable before opening it, otherwise * libvirt emits an error. */ @@ -290,10 +305,22 @@ int qemudLoadDriverConfig(struct qemud_driver *driver, } } + p = virConfGetValue (conf, "hugetlbfs_mount"); + CHECK_TYPE ("hugetlbfs_mount", VIR_CONF_STRING); + if (p && p->str) { + VIR_FREE(driver->hugetlbfs_mount); + if (!(driver->hugetlbfs_mount = strdup(p->str))) { + virReportOOMError(NULL); + virConfFree(conf); + return -1; + } + } +

virConfFree (conf); return 0; } +

diff --git a/src/qemu_driver.c b/src/qemu_driver.c index eb22940..4140a63 100644 --- a/src/qemu_driver.c +++ b/src/qemu_driver.c @@ -542,6 +542,38 @@ qemudStartup(int privileged) { goto error; } + /* If hugetlbfs is present, then we need to create a sub-directory within + * it, since we can't assume the root mount point has permissions that + * will let our spawned QEMU instances use it. + * + * NB the check for '/', since user may config "" to disable hugepages + * even when mounted + */ + if (qemu_driver->hugetlbfs_mount && + qemu_driver->hugetlbfs_mount[0] == '/') { + char *mempath = NULL; + int ret;

+ if (virAsprintf(&mempath, "%s/libvirt/qemu", qemu_driver->hugetlbfs_mount) < 0) + goto out_of_memory; + + if ((ret = virFileMakePath(mempath)) != 0) { + virReportSystemError(NULL, ret, + _("unable to create hugepage path %s"), mempath); + VIR_FREE(mempath); + goto error; + } + if (qemu_driver->privileged && + chown(mempath, qemu_driver->user, qemu_driver->group) < 0) { + virReportSystemError(NULL, errno, + _("unable to set ownership on %s to %d:%d"), + mempath, qemu_driver->user, qemu_driver->group); + VIR_FREE(mempath); + goto error; + } + + qemu_driver->hugepage_path = mempath; + } + /* Get all the running persistent or transient configs first */ if (virDomainLoadAllConfigs(NULL, qemu_driver->caps, @@ -673,6 +705,8 @@ qemudShutdown(void) { VIR_FREE(qemu_driver->vncPassword); VIR_FREE(qemu_driver->vncSASLdir); VIR_FREE(qemu_driver->saveImageFormat); + VIR_FREE(qemu_driver->hugetlbfs_mount); + VIR_FREE(qemu_driver->hugepage_path); /* Free domain callback list */ virDomainEventCallbackListFree(qemu_driver->domainEventCallbacks); diff --git a/src/util.c b/src/util.c index 0d4f3fa..35efee2 100644 --- a/src/util.c +++ b/src/util.c @@ -60,7 +60,9 @@ #if HAVE_CAPNG #include <cap-ng.h> #endif - +#ifdef HAVE_MNTENT_H +#include <mntent.h> +#endif #include "virterror_internal.h" #include "logging.h" @@ -1983,3 +1985,36 @@ int virGetGroupID(virConnectPtr conn, return 0; } #endif + + +#ifdef HAVE_MNTENT_H

+/* search /proc/mounts for mount point of *type; return pointer to + * malloc'ed string of the path if found, otherwise return NULL + */ +char *virFileFindMountPoint(const char *type) +{ + FILE *f; + struct mntent mb; + char mntbuf[1024]; + char *ret = NULL; + + f = setmntent("/proc/mounts", "r"); + if (!f) + return NULL; + + while (getmntent_r(f, &mb, mntbuf, sizeof(mntbuf))) { + if (STREQ(mb.mnt_type, type)) { + ret = strdup(mb.mnt_dir);

+ goto cleanup; + } + } + +cleanup: + endmntent(f); + + if (!ret) + errno = ENOENT;