xc_domain_getinfolist() internally relies on a sysctl that performs
a linear search for the domids. Many callers of xc_domain_getinfolist()
who require information about a precise domid are much better off calling
xc_domain_getinfo_single() instead, that will use the getdomaininfo domctl
instead and ensure the returned domid matches the requested one. The domtctl
will find the domid faster too, because that uses hashed lists.
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
It currently relies on xc_domain_getinfo() returning the next available
domain past "first_domid", which is a feature that will disappear in a
future patch.
Furthermore and while at it, make it so the hypercall tries to fetch information
about more than one domain per hypercall so we can (hopefully) get away with a
single hypercall in a typical system.
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
It has 2 avoidable occurences
* Check whether a domain is valid, which can be done faster with
xc_domain_getinfo_single().
* Domain discovery, which can be done in a race-free way with the sysctl
interface through xc_domain_getinfolist().
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
It's a stricter version of xc_domain_getinfo() where the returned domid
always matches the requested domid or the error code shows an error instead.
A few patches ahead usages of xc_domain_getinfo() are removed until only
xc_domain_getinfo_single() and xc_domain_getinfolist() remain.
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
xc_domain_getinfo() is slow and prone to races because N hypercalls are
needed to find information about N domains. xc_domain_getinfolist() finds
the same information in a single hypercall as long as a big enough buffer
is provided. Plus, xc_domain_getinfo() is disappearing on a future patch
so migrate the callers interested in more than 1 domain to the the *list()
version.
Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Alejandro Vallejo