one small question ...
On Tue, Oct 21, 2008 at 6:11 AM, Alan Jenkins
<alan-jenkins@xxxxxxxxxxxxxx> wrote:
> Allocate udev_device->envp lazily
>
> It's a pity to allocate 128 words when we don't need them.
> Measured 2% _user_ cpu time reduction on EeePC coldplug.
>
> Signed-off-by: Alan Jenkins <alan-jenkins@xxxxxxxxxxxxxx>
>
> diff --git a/udev/lib/libudev-device.c b/udev/lib/libudev-device.c
> index b54c727..69ab1f7 100644
> --- a/udev/lib/libudev-device.c
> +++ b/udev/lib/libudev-device.c
> @@ -31,6 +31,8 @@
> #include "libudev.h"
> #include "libudev-private.h"
>
> +#define ENVP_SIZE 128
> +
> struct udev_device {
> int refcount;
> struct udev *udev;
> @@ -46,7 +48,7 @@ struct udev_device {
> struct udev_list_node devlinks_list;
> int devlinks_uptodate;
> struct udev_list_node properties_list;
> - char *envp[128];
> + char **envp;
> int envp_uptodate;
> char *driver;
> int driver_set;
> @@ -611,8 +613,11 @@ void udev_device_unref(struct udev_device *udev_device)
> free(udev_device->devpath_old);
> free(udev_device->physdevpath);
> udev_list_cleanup_entries(udev_device->udev, &udev_device->sysattr_list);
> - for (i = 0; i < ARRAY_SIZE(udev_device->envp) && udev_device->envp[i] != NULL; i++)
> - free(udev_device->envp[i]);
> + if (udev_device->envp != NULL) {
> + for (i = 0; i < ENVP_SIZE && udev_device->envp[i] != NULL; i++)
> + free(udev_device->envp[i]);
> + free(udev_device->envp);
> + }
> info(udev_device->udev, "udev_device: %p released\n", udev_device);
> free(udev_device);
> }
> @@ -1014,14 +1019,18 @@ char **udev_device_get_properties_envp(struct udev_device *udev_device)
> unsigned int i;
> struct udev_list_entry *list_entry;
>
> - for (i = 0; i < ARRAY_SIZE(udev_device->envp) && udev_device->envp[i] != NULL; i++)
> - free(udev_device->envp[i]);
> + if (udev_device->envp) {
> + for (i = 0; i < 128 && udev_device->envp[i] != NULL; i++)
should this 128 also be ENVP_SIZE?
> + free(udev_device->envp[i]);
> + } else
> + udev_device->envp = malloc(sizeof(char *) * ENVP_SIZE);
> +
> i = 0;
> udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
> asprintf(&udev_device->envp[i++], "%s=%s",
> udev_list_entry_get_name(list_entry),
> udev_list_entry_get_value(list_entry));
> - if (i+1 >= ARRAY_SIZE(udev_device->envp))
> + if (i+1 >= ENVP_SIZE)
> break;
> }
> udev_device->envp[i] = NULL;
>
>
-Bob
--
To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
