From: Laurent Dufour <ldufour@linux.ibm.com>
To: mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org
Cc: nathanl@linux.ibm.com, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Subject: Re: [PATCH v2] ppc64/numa: consider the max numa node for migratable LPAR
Date: Thu, 1 Jul 2021 10:36:12 +0200 [thread overview]
Message-ID: <dd5e73b1-bc65-dd4a-828c-314fc2eeea64@linux.ibm.com> (raw)
In-Reply-To: <20210511073136.17795-1-ldufour@linux.ibm.com>
Hi Michael,
Do you mind taking this patch of 5.14?
Thanks,
Laurent.
Le 11/05/2021 à 09:31, Laurent Dufour a écrit :
> When a LPAR is migratable, we should consider the maximum possible NUMA
> node instead the number of NUMA node from the actual system.
>
> The DT property 'ibm,current-associativity-domains' is defining the maximum
> number of nodes the LPAR can see when running on that box. But if the LPAR
> is being migrated on another box, it may seen up to the nodes defined by
> 'ibm,max-associativity-domains'. So if a LPAR is migratable, that value
> should be used.
>
> Unfortunately, there is no easy way to know if a LPAR is migratable or
> not. The hypervisor is exporting the property 'ibm,migratable-partition' in
> the case it set to migrate partition, but that would not mean that the
> current partition is migratable.
>
> Without this patch, when a LPAR is started on a 2 nodes box and then
> migrated to a 3 nodes box, the hypervisor may spread the LPAR's CPUs on the
> 3rd node. In that case if a CPU from that 3rd node is added to the LPAR, it
> will be wrongly assigned to the node because the kernel has been set to use
> up to 2 nodes (the configuration of the departure node). With this patch
> applies, the CPU is correctly added to the 3rd node.
>
> Fixes: f9f130ff2ec9 ("powerpc/numa: Detect support for coregroup")
> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
> ---
> V2: Address Srikar's comments
> - Fix the commit message
> - Use pr_info instead printk(KERN_INFO..)
> ---
> arch/powerpc/mm/numa.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index f2bf98bdcea2..094a1076fd1f 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -893,7 +893,7 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
> static void __init find_possible_nodes(void)
> {
> struct device_node *rtas;
> - const __be32 *domains;
> + const __be32 *domains = NULL;
> int prop_length, max_nodes;
> u32 i;
>
> @@ -909,9 +909,14 @@ static void __init find_possible_nodes(void)
> * it doesn't exist, then fallback on ibm,max-associativity-domains.
> * Current denotes what the platform can support compared to max
> * which denotes what the Hypervisor can support.
> + *
> + * If the LPAR is migratable, new nodes might be activated after a LPM,
> + * so we should consider the max number in that case.
> */
> - domains = of_get_property(rtas, "ibm,current-associativity-domains",
> - &prop_length);
> + if (!of_get_property(of_root, "ibm,migratable-partition", NULL))
> + domains = of_get_property(rtas,
> + "ibm,current-associativity-domains",
> + &prop_length);
> if (!domains) {
> domains = of_get_property(rtas, "ibm,max-associativity-domains",
> &prop_length);
> @@ -920,6 +925,8 @@ static void __init find_possible_nodes(void)
> }
>
> max_nodes = of_read_number(&domains[min_common_depth], 1);
> + pr_info("Partition configured for %d NUMA nodes.\n", max_nodes);
> +
> for (i = 0; i < max_nodes; i++) {
> if (!node_possible(i))
> node_set(i, node_possible_map);
>
next prev parent reply other threads:[~2021-07-01 8:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 7:31 [PATCH v2] ppc64/numa: consider the max numa node for migratable LPAR Laurent Dufour
2021-07-01 8:36 ` Laurent Dufour [this message]
2021-07-19 9:12 ` Laurent Dufour
2021-08-18 13:38 ` Michael Ellerman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=dd5e73b1-bc65-dd4a-828c-314fc2eeea64@linux.ibm.com \
--to=ldufour@linux.ibm.com \
--cc=benh@kernel.crashing.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=nathanl@linux.ibm.com \
--cc=paulus@samba.org \
--cc=srikar@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).