It will cause significant performance regressions in some situations as Andrew mentioned in [1]. The main situation is vmalloc, vmalloc will allocate pages with NUMA_NO_NODE by default, that will result in alloc page one by one; In order to solve this, __alloc_pages_bulk and mempolicy should be considered at the same time. 1) If node is specified in memory allocation request, it will alloc all pages by __alloc_pages_bulk. 2) If interleaving allocate memory, it will cauculate how many pages should be allocated in each node, and use __alloc_pages_bulk to alloc pages in each node. [1]: https://lore.kernel.org/lkml/CALvZod4G3SzP3kWxQYn0fj+VgG-G3yWXz=gz17+3N57ru1iajw@xxxxxxxxxxxxxx/t/#m750c8e3231206134293b089feaa090590afa0f60 Signed-off-by: Chen Wandun <chenwandun@xxxxxxxxxx> ---------------- based on "[PATCH] mm/vmalloc: fix numa spreading for large hash tables" --- include/linux/gfp.h | 4 +++ mm/mempolicy.c | 76 +++++++++++++++++++++++++++++++++++++++++++++ mm/vmalloc.c | 19 +++--------- 3 files changed, 85 insertions(+), 14 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 558299cb2970..b976c4177299 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -531,6 +531,10 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, struct list_head *page_list, struct page **page_array); +unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp, + unsigned long nr_pages, + struct page **page_array); + /* Bulk allocate order-0 pages */ static inline unsigned long alloc_pages_bulk_list(gfp_t gfp, unsigned long nr_pages, struct list_head *list) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 9f8cd1457829..f456c5eb8d10 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2196,6 +2196,82 @@ struct page *alloc_pages(gfp_t gfp, unsigned order) } EXPORT_SYMBOL(alloc_pages); +unsigned long alloc_pages_bulk_array_interleave(gfp_t gfp, + struct mempolicy *pol, unsigned long nr_pages, + struct page **page_array) +{ + int nodes; + unsigned long nr_pages_per_node; + int delta; + int i; + unsigned long nr_allocated; + unsigned long total_allocated = 0; + + nodes = nodes_weight(pol->nodes); + nr_pages_per_node = nr_pages / nodes; + delta = nr_pages - nodes * nr_pages_per_node; + + for (i = 0; i < nodes; i++) { + if (delta) { + nr_allocated = __alloc_pages_bulk(gfp, + interleave_nodes(pol), NULL, + nr_pages_per_node + 1, NULL, + page_array); + delta--; + } else { + nr_allocated = __alloc_pages_bulk(gfp, + interleave_nodes(pol), NULL, + nr_pages_per_node, NULL, page_array); + } + + page_array += nr_allocated; + total_allocated += nr_allocated; + } + + return total_allocated; +} + +unsigned long alloc_pages_bulk_array_preferred_many(gfp_t gfp, int nid, + struct mempolicy *pol, unsigned long nr_pages, + struct page **page_array) +{ + gfp_t preferred_gfp; + unsigned long nr_allocated = 0; + + preferred_gfp = gfp | __GFP_NOWARN; + preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL); + + nr_allocated = __alloc_pages_bulk(preferred_gfp, nid, &pol->nodes, + nr_pages, NULL, page_array); + + if (nr_allocated < nr_pages) + nr_allocated += __alloc_pages_bulk(gfp, numa_node_id(), NULL, + nr_pages - nr_allocated, NULL, + page_array + nr_allocated); + return nr_allocated; +} + +unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp, + unsigned long nr_pages, struct page **page_array) +{ + struct mempolicy *pol = &default_policy; + + if (!in_interrupt() && !(gfp & __GFP_THISNODE)) + pol = get_task_policy(current); + + if (pol->mode == MPOL_INTERLEAVE) + return alloc_pages_bulk_array_interleave(gfp, pol, + nr_pages, page_array); + + if (pol->mode == MPOL_PREFERRED_MANY) + return alloc_pages_bulk_array_preferred_many(gfp, + numa_node_id(), pol, nr_pages, page_array); + + return __alloc_pages_bulk(gfp, policy_node(gfp, pol, numa_node_id()), + policy_nodemask(gfp, pol), nr_pages, NULL, + page_array); +} + struct folio *folio_alloc(gfp_t gfp, unsigned order) { struct page *page = alloc_pages(gfp | __GFP_COMP, order); diff --git a/mm/vmalloc.c b/mm/vmalloc.c index b7ac4a8fe2b3..49adba793f3c 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2856,23 +2856,14 @@ vm_area_alloc_pages(gfp_t gfp, int nid, */ nr_pages_request = min(100U, nr_pages - nr_allocated); - if (nid == NUMA_NO_NODE) { - for (i = 0; i < nr_pages_request; i++) { - page = alloc_page(gfp); - if (page) - pages[nr_allocated + i] = page; - else { - nr = i; - break; - } - } - if (i >= nr_pages_request) - nr = nr_pages_request; - } else { + if (nid == NUMA_NO_NODE) + nr = alloc_pages_bulk_array_mempolicy(gfp, + nr_pages_request, + pages + nr_allocated); + else nr = alloc_pages_bulk_array_node(gfp, nid, nr_pages_request, pages + nr_allocated); - } nr_allocated += nr; cond_resched(); -- 2.25.1
