From 1941b31482a61a7bd75300d1905938e7e48c3d25 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Mon, 19 Aug 2024 11:54:05 -0700 Subject: [PATCH] Reenable NUMA policy support in the slab allocator Revert commit 8014c46ad991 ("slub: use alloc_pages_node() in alloc_slab_page()"). The patch disabled the numa policy support in the slab allocator. It did not consider that alloc_pages() uses memory policies but alloc_pages_node() does not. As a result of this patch slab memory allocations are no longer spread via interleave policy across all available NUMA nodes on bootup. Instead all slab memory is allocated close to the boot processor. This leads to an imbalance of memory accesses on NUMA systems. Also applications using MPOL_INTERLEAVE as a memory policy will no longer spread slab allocations over all nodes in the interleave set but allocate memory locally. This may also result in unbalanced allocations on a single numa node. SLUB does not apply memory policies to individual object allocations. However, it relies on the page allocators support of memory policies through alloc_pages() to do the NUMA memory allocations on a per folio or page level. SLUB also applies memory policies when retrieving partial allocated slab pages from the partial list. Fixes: 8014c46ad991 ("slub: use alloc_pages_node() in alloc_slab_page()") Signed-off-by: Christoph Lameter Reviewed-by: Yang Shi Signed-off-by: Vlastimil Babka --- mm/slub.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/slub.c b/mm/slub.c index 3088260bf75d..60004bfc2dc2 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2318,7 +2318,11 @@ static inline struct slab *alloc_slab_page(gfp_t flags, int node, struct slab *slab; unsigned int order = oo_order(oo); - folio = (struct folio *)alloc_pages_node(node, flags, order); + if (node == NUMA_NO_NODE) + folio = (struct folio *)alloc_pages(flags, order); + else + folio = (struct folio *)__alloc_pages_node(node, flags, order); + if (!folio) return NULL;