Messages in this thread Patch in this message |  | | From | Laurent Dufour <> | Subject | [PATCH] powerpc/drmem: Don't compute the NUMA node for each LMB | Date | Wed, 5 Aug 2020 11:28:58 +0200 |
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All the LMB from the same set of ibm,dynamic-memory-v2 property are sharing the same NUMA node. Don't compute that node for each one.
Tested on a system with 1022 LMBs spread on 4 NUMA nodes, only 4 calls to lmb_set_nid() have been made instead of 1022.
This should prevent some soft lockups when starting large guests
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com> --- arch/powerpc/mm/drmem.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/drmem.c b/arch/powerpc/mm/drmem.c index b2eeea39684c..3819c523c65b 100644 --- a/arch/powerpc/mm/drmem.c +++ b/arch/powerpc/mm/drmem.c @@ -397,7 +397,7 @@ static void __init init_drmem_v1_lmbs(const __be32 *prop) static void __init init_drmem_v2_lmbs(const __be32 *prop) { - struct drmem_lmb *lmb; + struct drmem_lmb *lmb, *first; struct of_drconf_cell_v2 dr_cell; const __be32 *p; u32 i, j, lmb_sets; @@ -422,10 +422,18 @@ static void __init init_drmem_v2_lmbs(const __be32 *prop) /* second pass, read in the LMB information */ lmb_index = 0; p = prop; + first = NULL; for (i = 0; i < lmb_sets; i++) { read_drconf_v2_cell(&dr_cell, &p); + /* + * Fetch the NUMA node id for the fist set or if the + * associativity index is different from the previous set. + */ + if (first && dr_cell.aa_index != first->aa_index) + first = NULL; + for (j = 0; j < dr_cell.seq_lmbs; j++) { lmb = &drmem_info->lmbs[lmb_index++]; @@ -438,7 +446,16 @@ static void __init init_drmem_v2_lmbs(const __be32 *prop) lmb->aa_index = dr_cell.aa_index; lmb->flags = dr_cell.flags; - lmb_set_nid(lmb); + /* + * All the LMB in the set share the same NUMA + * associativity property. So read that node only once. + */ + if (!first) { + lmb_set_nid(lmb); + first = lmb; + } else { + lmb->nid = first->nid; + } } } } -- 2.28.0
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