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| author | Vishal Moola (Oracle) <vishal.moola@gmail.com> | 2025-10-21 12:44:56 -0700 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-11-16 17:28:15 -0800 |
| commit | a0615780439938e8e61343f1f92a4c54a71dc6a5 (patch) | |
| tree | 52bc877a7737b271bb4316c5b25222440a572dea /mm/vmalloc.c | |
| parent | 645a3c4243473d5c8b780927d2cc573e3da5a20c (diff) | |
mm/vmalloc: request large order pages from buddy allocator
Sometimes, vm_area_alloc_pages() will want many pages from the buddy
allocator. Rather than making requests to the buddy allocator for at most
100 pages at a time, we can eagerly request large order pages a smaller
number of times.
We still split the large order pages down to order-0 as the rest of the
vmalloc code (and some callers) depend on it. We still defer to the bulk
allocator and fallback path in case of order-0 pages or failure.
Running 1000 iterations of allocations on a small 4GB system finds:
1000 2mb allocations:
[Baseline] [This patch]
real 46.310s real 0m34.582
user 0.001s user 0.006s
sys 46.058s sys 0m34.365s
10000 200kb allocations:
[Baseline] [This patch]
real 56.104s real 0m43.696
user 0.001s user 0.003s
sys 55.375s sys 0m42.995s
Link: https://lkml.kernel.org/r/20251021194455.33351-2-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/vmalloc.c')
| -rw-r--r-- | mm/vmalloc.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index adde450ddf5e..0832f944544c 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3619,8 +3619,44 @@ vm_area_alloc_pages(gfp_t gfp, int nid, unsigned int order, unsigned int nr_pages, struct page **pages) { unsigned int nr_allocated = 0; + unsigned int nr_remaining = nr_pages; + unsigned int max_attempt_order = MAX_PAGE_ORDER; struct page *page; int i; + gfp_t large_gfp = (gfp & + ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL | __GFP_COMP)) + | __GFP_NOWARN; + unsigned int large_order = ilog2(nr_remaining); + + large_order = min(max_attempt_order, large_order); + + /* + * Initially, attempt to have the page allocator give us large order + * pages. Do not attempt allocating smaller than order chunks since + * __vmap_pages_range() expects physically contigous pages of exactly + * order long chunks. + */ + while (large_order > order && nr_remaining) { + if (nid == NUMA_NO_NODE) + page = alloc_pages_noprof(large_gfp, large_order); + else + page = alloc_pages_node_noprof(nid, large_gfp, large_order); + + if (unlikely(!page)) { + max_attempt_order = --large_order; + continue; + } + + split_page(page, large_order); + for (i = 0; i < (1U << large_order); i++) + pages[nr_allocated + i] = page + i; + + nr_allocated += 1U << large_order; + nr_remaining = nr_pages - nr_allocated; + + large_order = ilog2(nr_remaining); + large_order = min(max_attempt_order, large_order); + } /* * For order-0 pages we make use of bulk allocator, if |