Mailing List Archive

[PATCH v3] tools/libs/light: update xenstore entry when setting max domain memory
libxl_domain_setmaxmem() called during "xl mem-max" should update the
domain's memory/static-max Xenstore node, as otherwise "xl mem-set"
won't be able to set the memory size to the new maximum.

Adjust the related comments and documentation accordingly.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- adjust comments and docs (Anthony Perard)
V3:
- really adjust the docs (Anthony Perard)
---
docs/man/xl.1.pod.in | 11 +++++------
tools/libs/light/libxl_mem.c | 12 ++++++++++--
2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/docs/man/xl.1.pod.in b/docs/man/xl.1.pod.in
index e2176bd696..101e14241d 100644
--- a/docs/man/xl.1.pod.in
+++ b/docs/man/xl.1.pod.in
@@ -442,15 +442,14 @@ allocate.
The default unit is kiB. Add 't' for TiB, 'g' for GiB, 'm' for
MiB, 'k' for kiB, and 'b' for bytes (e.g., `2048m` for 2048 MiB).

-NB that users normally shouldn't need this command; B<xl mem-set> will
-set this as appropriate automatically.
-
I<mem> can't be set lower than the current memory target for
I<domain-id>. It is allowed to be higher than the configured maximum
memory size of the domain (B<maxmem> parameter in the domain's
-configuration). Note however that the initial B<maxmem> value is still
-used as an upper limit for B<xl mem-set>. Also note that calling B<xl
-mem-set> will reset this value.
+configuration).
+
+Setting the maximum memory size above the configured maximum memory size
+will require special guest support (memory hotplug) in order to be usable
+by the guest.

The domain will not receive any signal regarding the changed memory
limit.
diff --git a/tools/libs/light/libxl_mem.c b/tools/libs/light/libxl_mem.c
index c739d00f39..92ec09f4cf 100644
--- a/tools/libs/light/libxl_mem.c
+++ b/tools/libs/light/libxl_mem.c
@@ -20,8 +20,7 @@
/*
* Set the maximum memory size of the domain in the hypervisor. There is no
* change of the current memory size involved. The specified memory size can
- * even be above the configured maxmem size of the domain, but the related
- * Xenstore entry memory/static-max isn't modified!
+ * even be above the configured maxmem size of the domain.
*/
int libxl_domain_setmaxmem(libxl_ctx *ctx, uint32_t domid, uint64_t max_memkb)
{
@@ -82,6 +81,15 @@ int libxl_domain_setmaxmem(libxl_ctx *ctx, uint32_t domid, uint64_t max_memkb)
goto out;
}

+ rc = libxl__xs_printf(gc, XBT_NULL,
+ GCSPRINTF("%s/memory/static-max", dompath),
+ "%"PRIu64, max_memkb);
+ if (rc != 0) {
+ LOGED(ERROR, domid, "Couldn't set %s/memory/static-max, rc=%d\n",
+ dompath, rc);
+ goto out;
+ }
+
rc = 0;
out:
libxl_domain_config_dispose(&d_config);
--
2.34.1
Re: [PATCH v3] tools/libs/light: update xenstore entry when setting max domain memory [ In reply to ]
Ping?

On 02.05.22 10:47, Juergen Gross wrote:
> libxl_domain_setmaxmem() called during "xl mem-max" should update the
> domain's memory/static-max Xenstore node, as otherwise "xl mem-set"
> won't be able to set the memory size to the new maximum.
>
> Adjust the related comments and documentation accordingly.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
> V2:
> - adjust comments and docs (Anthony Perard)
> V3:
> - really adjust the docs (Anthony Perard)
> ---
> docs/man/xl.1.pod.in | 11 +++++------
> tools/libs/light/libxl_mem.c | 12 ++++++++++--
> 2 files changed, 15 insertions(+), 8 deletions(-)
>
> diff --git a/docs/man/xl.1.pod.in b/docs/man/xl.1.pod.in
> index e2176bd696..101e14241d 100644
> --- a/docs/man/xl.1.pod.in
> +++ b/docs/man/xl.1.pod.in
> @@ -442,15 +442,14 @@ allocate.
> The default unit is kiB. Add 't' for TiB, 'g' for GiB, 'm' for
> MiB, 'k' for kiB, and 'b' for bytes (e.g., `2048m` for 2048 MiB).
>
> -NB that users normally shouldn't need this command; B<xl mem-set> will
> -set this as appropriate automatically.
> -
> I<mem> can't be set lower than the current memory target for
> I<domain-id>. It is allowed to be higher than the configured maximum
> memory size of the domain (B<maxmem> parameter in the domain's
> -configuration). Note however that the initial B<maxmem> value is still
> -used as an upper limit for B<xl mem-set>. Also note that calling B<xl
> -mem-set> will reset this value.
> +configuration).
> +
> +Setting the maximum memory size above the configured maximum memory size
> +will require special guest support (memory hotplug) in order to be usable
> +by the guest.
>
> The domain will not receive any signal regarding the changed memory
> limit.
> diff --git a/tools/libs/light/libxl_mem.c b/tools/libs/light/libxl_mem.c
> index c739d00f39..92ec09f4cf 100644
> --- a/tools/libs/light/libxl_mem.c
> +++ b/tools/libs/light/libxl_mem.c
> @@ -20,8 +20,7 @@
> /*
> * Set the maximum memory size of the domain in the hypervisor. There is no
> * change of the current memory size involved. The specified memory size can
> - * even be above the configured maxmem size of the domain, but the related
> - * Xenstore entry memory/static-max isn't modified!
> + * even be above the configured maxmem size of the domain.
> */
> int libxl_domain_setmaxmem(libxl_ctx *ctx, uint32_t domid, uint64_t max_memkb)
> {
> @@ -82,6 +81,15 @@ int libxl_domain_setmaxmem(libxl_ctx *ctx, uint32_t domid, uint64_t max_memkb)
> goto out;
> }
>
> + rc = libxl__xs_printf(gc, XBT_NULL,
> + GCSPRINTF("%s/memory/static-max", dompath),
> + "%"PRIu64, max_memkb);
> + if (rc != 0) {
> + LOGED(ERROR, domid, "Couldn't set %s/memory/static-max, rc=%d\n",
> + dompath, rc);
> + goto out;
> + }
> +
> rc = 0;
> out:
> libxl_domain_config_dispose(&d_config);
Re: [PATCH v3] tools/libs/light: update xenstore entry when setting max domain memory [ In reply to ]
On Mon, May 02, 2022 at 10:47:29AM +0200, Juergen Gross wrote:
> libxl_domain_setmaxmem() called during "xl mem-max" should update the
> domain's memory/static-max Xenstore node, as otherwise "xl mem-set"
> won't be able to set the memory size to the new maximum.
>
> Adjust the related comments and documentation accordingly.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>

Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>

Thanks,

--
Anthony PERARD