[PATCH 0/2] Optimize initialization of storage files
See 2/2. Peter Krempa (2): qemuSecurityChownCallback: Remove 'cleanup' section qemuSecurityChownCallback: Don't initialize storage file subsystem for local file src/qemu/qemu_driver.c | 31 +++++++++++++------------------ 1 file changed, 13 insertions(+), 18 deletions(-) -- 2.24.1
Treat the shortcut for chowning local files as a stand-alone section by returning success from it and refactor the rest so that the cleanup section is inline. Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- src/qemu/qemu_driver.c | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 570dc059e9..b1f7be50b4 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -268,24 +268,20 @@ qemuSecurityChownCallback(const virStorageSource *src, } if (chown(src->path, uid, gid) < 0) - goto cleanup; - } else { - if (!(cpy = virStorageSourceCopy(src, false))) - goto cleanup; - - /* src file init reports errors, return -2 on failure */ - if (virStorageFileInit(cpy) < 0) { - ret = -2; - goto cleanup; - } + return -1; - if (virStorageFileChown(cpy, uid, gid) < 0) - goto cleanup; + return 0; } - ret = 0; + if (!(cpy = virStorageSourceCopy(src, false))) + return -1; + + /* src file init reports errors, return -2 on failure */ + if (virStorageFileInit(cpy) < 0) + return -2; + + ret = virStorageFileChown(cpy, uid, gid); - cleanup: save_errno = errno; virStorageFileDeinit(cpy); errno = save_errno; -- 2.24.1
virStorageFileSupportsSecurityDriver ends up initializing the storage file backend which after the recent changes to the daemon architecture may end up dlopening of the backend modules. Since this is required only for remote storage we can optimize the call by moving the check whether the backend is supported to the branch which deals with remote storage. This will prevent the pointless dlopen for local files. This is amplified by the fact that we now do most storage driver operations in forks so the storage backends may not even be initialized in the main daemon. On the other hand, not having gluster linked in the main daemon is a big win, so we should keep only the forks having to link with it. Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- src/qemu/qemu_driver.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index b1f7be50b4..3cbd900f7e 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -249,10 +249,6 @@ qemuSecurityChownCallback(const virStorageSource *src, int rv; g_autoptr(virStorageSource) cpy = NULL; - rv = virStorageFileSupportsSecurityDriver(src); - if (rv <= 0) - return rv; - if (virStorageSourceIsLocalStorage(src)) { /* use direct chown for local files so that the file doesn't * need to be initialized */ @@ -273,6 +269,9 @@ qemuSecurityChownCallback(const virStorageSource *src, return 0; } + if ((rv = virStorageFileSupportsSecurityDriver(src)) <= 0) + return rv; + if (!(cpy = virStorageSourceCopy(src, false))) return -1; -- 2.24.1
On Thu, Mar 26, 2020 at 12:18:03 +0100, Peter Krempa wrote:
virStorageFileSupportsSecurityDriver ends up initializing the storage file backend which after the recent changes to the daemon architecture may end up dlopening of the backend modules.
Since this is required only for remote storage we can optimize the call by moving the check whether the backend is supported to the branch which deals with remote storage. This will prevent the pointless dlopen for local files.
This is amplified by the fact that we now do most storage driver operations in forks so the storage backends may not even be initialized in the main daemon. On the other hand, not having gluster linked in the main daemon is a big win, so we should keep only the forks having to link with it.
Actually, I'll redact this as standard startup of a VM still invokes the storage file backends, so they will be linked eventually on normal usage. I've observed this after libvirtd restart.
On Thu, Mar 26, 2020 at 12:18:01PM +0100, Peter Krempa wrote:
See 2/2.
Peter Krempa (2): qemuSecurityChownCallback: Remove 'cleanup' section qemuSecurityChownCallback: Don't initialize storage file subsystem for local file
src/qemu/qemu_driver.c | 31 +++++++++++++------------------ 1 file changed, 13 insertions(+), 18 deletions(-)
-- 2.24.1
Reviewed-by: Pavel Mores <pmores@redhat.com>
participants (2)
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Pavel Mores -
Peter Krempa