[libvirt] [PATCH v3 01/20] Add a qemu capabilities cache manager

[Doug Goldstein]

On Tue, Sep 25, 2012 at 12:59 PM, Daniel P. Berrange
<berrange at redhat.com> wrote:
> From: "Daniel P. Berrange" <berrange at redhat.com>
>
> Introduce a qemuCapsCachePtr object to provide a global cache
> of capabilities for QEMU binaries. The cache auto-populates
> on first request for capabilities about a binary, and will
> auto-refresh if the binary has changed since a previous cache
> was populated
>
> Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
> ---
>  src/qemu/qemu_capabilities.c | 99 ++++++++++++++++++++++++++++++++++++++++++++
>  src/qemu/qemu_capabilities.h |  9 ++++
>  2 files changed, 108 insertions(+)
>
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index 3b08ef8..1163dd8 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -206,6 +206,11 @@ struct _qemuCaps {
>      char **machineAliases;
>  };
>
> +struct _qemuCapsCache {
> +    virMutex lock;
> +    virHashTablePtr binaries;
> +};
> +
>
>  static virClassPtr qemuCapsClass;
>  static void qemuCapsDispose(void *obj);
> @@ -1940,6 +1945,10 @@ qemuCapsPtr qemuCapsNewForBinary(const char *binary)
>      tmp = strstr(binary, QEMU_SYSTEM_PREFIX);
>      if (tmp) {
>          tmp += strlen(QEMU_SYSTEM_PREFIX);
> +
> +        /* For historical compat we uses 'itanium' as arch name */

s/uses/use/

> +        if (STREQ(tmp, "ia64"))
> +            tmp = "itanium";
>      } else {
>          uname_normalize(&ut);
>          tmp = ut.machine;
> @@ -2048,3 +2057,93 @@ bool qemuCapsIsValid(qemuCapsPtr caps)
>
>      return sb.st_mtime == caps->mtime;
>  }
> +
> +
> +static void
> +qemuCapsHashDataFree(void *payload, const void *key ATTRIBUTE_UNUSED)
> +{
> +    virObjectUnref(payload);
> +}
> +
> +qemuCapsCachePtr qemuCapsCacheNew(void)

Return type on its own line if I'm recalling the coding std.

> +{
> +    qemuCapsCachePtr cache;
> +
> +    if (VIR_ALLOC(cache) < 0) {
> +        virReportOOMError();
> +        return NULL;
> +    }
> +
> +    if (virMutexInit(&cache->lock) < 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("Unable to initialize mutex"));
> +        VIR_FREE(cache);
> +        return NULL;
> +    }
> +
> +    if (!(cache->binaries = virHashCreate(10, qemuCapsHashDataFree)))
> +        goto error;
> +
> +    return cache;
> +
> +error:
> +    qemuCapsCacheFree(cache);
> +    return NULL;
> +}
> +
> +
> +qemuCapsPtr qemuCapsCacheLookup(qemuCapsCachePtr cache, const char *binary)

Again.

> +{
> +    qemuCapsPtr ret = NULL;
> +    virMutexLock(&cache->lock);
> +    ret = virHashLookup(cache->binaries, binary);
> +    if (ret &&
> +        !qemuCapsIsValid(ret)) {
> +        VIR_DEBUG("Cached capabilities %p no longer valid for %s",
> +                  ret, binary);
> +        virHashRemoveEntry(cache->binaries, binary);
> +        ret = NULL;
> +    }
> +    if (!ret) {
> +        VIR_DEBUG("Creating capabilities for %s",
> +                  binary);
> +        ret = qemuCapsNewForBinary(binary);
> +        if (ret) {
> +            VIR_DEBUG("Caching capabilities %p for %s",
> +                      ret, binary);
> +            if (virHashAddEntry(cache->binaries, binary, ret) < 0) {
> +                virObjectUnref(ret);
> +                ret = NULL;
> +            }
> +        }
> +    }
> +    VIR_DEBUG("Returning caps %p for %s", ret, binary);
> +    virObjectRef(ret);
> +    virMutexUnlock(&cache->lock);
> +    return ret;
> +}
> +
> +
> +qemuCapsPtr qemuCapsCacheLookupCopy(qemuCapsCachePtr cache, const char *binary)

Again.

> +{
> +    qemuCapsPtr caps = qemuCapsCacheLookup(cache, binary);
> +    qemuCapsPtr ret;
> +
> +    if (!caps)
> +        return NULL;
> +
> +    ret = qemuCapsNewCopy(caps);
> +    virObjectUnref(caps);
> +    return ret;
> +}
> +
> +
> +void qemuCapsCacheFree(qemuCapsCachePtr cache)

Again.

> +{
> +    if (!cache)
> +        return;
> +
> +    virHashFree(cache->binaries);
> +    virMutexDestroy(&cache->lock);
> +    VIR_FREE(cache);
> +}
> diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
> index 485c297..27ed378 100644
> --- a/src/qemu/qemu_capabilities.h
> +++ b/src/qemu/qemu_capabilities.h
> @@ -154,6 +154,9 @@ enum qemuCapsFlags {
>  typedef struct _qemuCaps qemuCaps;
>  typedef qemuCaps *qemuCapsPtr;
>
> +typedef struct _qemuCapsCache qemuCapsCache;
> +typedef qemuCapsCache *qemuCapsCachePtr;
> +
>  qemuCapsPtr qemuCapsNew(void);
>  qemuCapsPtr qemuCapsNewCopy(qemuCapsPtr caps);
>  qemuCapsPtr qemuCapsNewForBinary(const char *binary);
> @@ -183,6 +186,12 @@ const char *qemuCapsGetCanonicalMachine(qemuCapsPtr caps,
>
>  bool qemuCapsIsValid(qemuCapsPtr caps);
>
> +
> +qemuCapsCachePtr qemuCapsCacheNew(void);
> +qemuCapsPtr qemuCapsCacheLookup(qemuCapsCachePtr cache, const char *binary);
> +qemuCapsPtr qemuCapsCacheLookupCopy(qemuCapsCachePtr cache, const char *binary);
> +void qemuCapsCacheFree(qemuCapsCachePtr cache);
> +
>  virCapsPtr qemuCapsInit(virCapsPtr old_caps);
>
>  int qemuCapsProbeMachineTypes(const char *binary,
> --
> 1.7.11.4
>
> --
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-- 
Doug Goldstein