Re: [PATCH v2 15/17] xen/cpupool: add cpupool directories

["Jürgen Groß" <jgross@suse.com>]

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On 01.12.20 09:21, Juergen Gross wrote:
> Add /cpupool/<cpupool-id> directories to hypfs. Those are completely
> dynamic, so the related hypfs access functions need to be implemented.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
> V2:
> - added const (Jan Beulich)
> - call hypfs_add_dir() in helper (Dario Faggioli)
> - switch locking to enter/exit callbacks
> ---
>   docs/misc/hypfs-paths.pandoc |   9 +++
>   xen/common/sched/cpupool.c   | 122 +++++++++++++++++++++++++++++++++++
>   2 files changed, 131 insertions(+)
> 
> diff --git a/docs/misc/hypfs-paths.pandoc b/docs/misc/hypfs-paths.pandoc
> index 6c7b2f7ee3..aaca1cdf92 100644
> --- a/docs/misc/hypfs-paths.pandoc
> +++ b/docs/misc/hypfs-paths.pandoc
> @@ -175,6 +175,15 @@ The major version of Xen.
>   
>   The minor version of Xen.
>   
> +#### /cpupool/
> +
> +A directory of all current cpupools.
> +
> +#### /cpupool/*/
> +
> +The individual cpupools. Each entry is a directory with the name being the
> +cpupool-id (e.g. /cpupool/0/).
> +
>   #### /params/
>   
>   A directory of runtime parameters.
> diff --git a/xen/common/sched/cpupool.c b/xen/common/sched/cpupool.c
> index 0db7d77219..3e17fdf95b 100644
> --- a/xen/common/sched/cpupool.c
> +++ b/xen/common/sched/cpupool.c
> @@ -13,6 +13,8 @@
>   
>   #include <xen/cpu.h>
>   #include <xen/cpumask.h>
> +#include <xen/guest_access.h>
> +#include <xen/hypfs.h>
>   #include <xen/init.h>
>   #include <xen/keyhandler.h>
>   #include <xen/lib.h>
> @@ -33,6 +35,7 @@ static int cpupool_moving_cpu = -1;
>   static struct cpupool *cpupool_cpu_moving = NULL;
>   static cpumask_t cpupool_locked_cpus;
>   
> +/* This lock nests inside sysctl or hypfs lock. */
>   static DEFINE_SPINLOCK(cpupool_lock);
>   
>   static enum sched_gran __read_mostly opt_sched_granularity = SCHED_GRAN_cpu;
> @@ -1003,12 +1006,131 @@ static struct notifier_block cpu_nfb = {
>       .notifier_call = cpu_callback
>   };
>   
> +#ifdef CONFIG_HYPFS
> +static const struct hypfs_entry *cpupool_pooldir_enter(
> +    const struct hypfs_entry *entry);
> +
> +static struct hypfs_funcs cpupool_pooldir_funcs = {
> +    .enter = cpupool_pooldir_enter,
> +    .exit = hypfs_node_exit,
> +    .read = hypfs_read_dir,
> +    .write = hypfs_write_deny,
> +    .getsize = hypfs_getsize,
> +    .findentry = hypfs_dir_findentry,
> +};
> +
> +static HYPFS_VARDIR_INIT(cpupool_pooldir, "%u", &cpupool_pooldir_funcs);
> +
> +static const struct hypfs_entry *cpupool_pooldir_enter(
> +    const struct hypfs_entry *entry)
> +{
> +    return &cpupool_pooldir.e;
> +}
I have found a more generic way to handle entering a dyndir node,
resulting in no need to have cpupool_pooldir_enter() and
cpupool_pooldir_funcs.

This will add some more lines to the previous patch, but less than
saved here.


Juergen

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