Hi Michael,
I sent this patch out several weeks ago, just wanted to make sure it hasn't
fallen
off your radar.
Thanks,
-Nathan
On 04/20/2018 03:29 PM, Nathan Fontenot wrote:
> The updates to powerpc numa and memory hotplug code now use the
> in-kernel LMB array instead of the device tree. This change
> allows the pseries memory DLPAR code to only update the device
> tree once after successfully handling a DLPAR request.
>
> Prior to the in-kernel LMB array, the numa code looked up the
> affinity for memory being added in the device tree, the code
> now looks this up in the LMB array. This change means the
> memory hotplug code can just update the affinity for an LMB
> in the LMB array instead of updating the device tree.
>
> This also provides a savings in kernel memory. When updating the
> device tree old properties are never free'ed since there is no
> usecount on properties. This behavior leads to a new copy of the
> property being allocated every time a LMB is added or removed
> (i.e. a request to add 100 LMBs creates 100 new copies of the
> property). With this update only a single new property is created
> when a DLPAR request completes successfully.
>
> Signed-off-by: Nathan Fontenot <nf...@linux.vnet.ibm.com>
> ---
> arch/powerpc/include/asm/drmem.h | 5 ++
> arch/powerpc/platforms/pseries/hotplug-memory.c | 55
> +++++++----------------
> 2 files changed, 21 insertions(+), 39 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/drmem.h
> b/arch/powerpc/include/asm/drmem.h
> index ce242b9ea8c6..7c1d8e74b25d 100644
> --- a/arch/powerpc/include/asm/drmem.h
> +++ b/arch/powerpc/include/asm/drmem.h
> @@ -99,4 +99,9 @@ void __init walk_drmem_lmbs_early(unsigned long node,
> void (*func)(struct drmem_lmb *, const __be32 **));
> #endif
>
> +static inline void invalidate_lmb_associativity_index(struct drmem_lmb *lmb)
> +{
> + lmb->aa_index = 0xffffffff;
> +}
> +
> #endif /* _ASM_POWERPC_LMB_H */
> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c
> b/arch/powerpc/platforms/pseries/hotplug-memory.c
> index c1578f54c626..9a15d39995e5 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
> @@ -163,7 +163,7 @@ static u32 find_aa_index(struct device_node *dr_node,
> return aa_index;
> }
>
> -static u32 lookup_lmb_associativity_index(struct drmem_lmb *lmb)
> +static int update_lmb_associativity_index(struct drmem_lmb *lmb)
> {
> struct device_node *parent, *lmb_node, *dr_node;
> struct property *ala_prop;
> @@ -203,43 +203,14 @@ static u32 lookup_lmb_associativity_index(struct
> drmem_lmb *lmb)
> aa_index = find_aa_index(dr_node, ala_prop, lmb_assoc);
>
> dlpar_free_cc_nodes(lmb_node);
> - return aa_index;
> -}
> -
> -static int dlpar_add_device_tree_lmb(struct drmem_lmb *lmb)
> -{
> - int rc, aa_index;
> -
> - lmb->flags |= DRCONF_MEM_ASSIGNED;
>
> - aa_index = lookup_lmb_associativity_index(lmb);
> if (aa_index < 0) {
> - pr_err("Couldn't find associativity index for drc index %x\n",
> - lmb->drc_index);
> - return aa_index;
> + pr_err("Could not find LMB associativity\n");
> + return -1;
> }
>
> lmb->aa_index = aa_index;
> -
> - rtas_hp_event = true;
> - rc = drmem_update_dt();
> - rtas_hp_event = false;
> -
> - return rc;
> -}
> -
> -static int dlpar_remove_device_tree_lmb(struct drmem_lmb *lmb)
> -{
> - int rc;
> -
> - lmb->flags &= ~DRCONF_MEM_ASSIGNED;
> - lmb->aa_index = 0xffffffff;
> -
> - rtas_hp_event = true;
> - rc = drmem_update_dt();
> - rtas_hp_event = false;
> -
> - return rc;
> + return 0;
> }
>
> static struct memory_block *lmb_to_memblock(struct drmem_lmb *lmb)
> @@ -428,7 +399,9 @@ static int dlpar_remove_lmb(struct drmem_lmb *lmb)
> /* Update memory regions for memory remove */
> memblock_remove(lmb->base_addr, block_sz);
>
> - dlpar_remove_device_tree_lmb(lmb);
> + invalidate_lmb_associativity_index(lmb);
> + lmb->flags &= ~DRCONF_MEM_ASSIGNED;
> +
> return 0;
> }
>
> @@ -688,10 +661,8 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
> if (lmb->flags & DRCONF_MEM_ASSIGNED)
> return -EINVAL;
>
> - rc = dlpar_add_device_tree_lmb(lmb);
> + rc = update_lmb_associativity_index(lmb);
> if (rc) {
> - pr_err("Couldn't update device tree for drc index %x\n",
> - lmb->drc_index);
> dlpar_release_drc(lmb->drc_index);
> return rc;
> }
> @@ -704,14 +675,14 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
> /* Add the memory */
> rc = add_memory(nid, lmb->base_addr, block_sz);
> if (rc) {
> - dlpar_remove_device_tree_lmb(lmb);
> + invalidate_lmb_associativity_index(lmb);
> return rc;
> }
>
> rc = dlpar_online_lmb(lmb);
> if (rc) {
> remove_memory(nid, lmb->base_addr, block_sz);
> - dlpar_remove_device_tree_lmb(lmb);
> + invalidate_lmb_associativity_index(lmb);
> } else {
> lmb->flags |= DRCONF_MEM_ASSIGNED;
> }
> @@ -958,6 +929,12 @@ int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
> break;
> }
>
> + if (!rc) {
> + rtas_hp_event = true;
> + rc = drmem_update_dt();
> + rtas_hp_event = false;
> + }
> +
> unlock_device_hotplug();
> return rc;
> }
>
