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authorYonghong Song <yonghong.song@linux.dev>2023-12-21 19:17:50 -0800
committerAlexei Starovoitov <ast@kernel.org>2024-01-03 21:08:25 -0800
commit5b95e638f134e552b5ba2976326c02babe248615 (patch)
treeea6a83156f646dd70e550b31b67c441f008da0a6 /kernel
parentc39aa3b289e9c10d0d246cd919b06809f13b72b8 (diff)
bpf: Refill only one percpu element in memalloc
Typically for percpu map element or data structure, once allocated, most operations are lookup or in-place update. Deletion are really rare. Currently, for percpu data strcture, 4 elements will be refilled if the size is <= 256. Let us just do with one element for percpu data. For example, for size 256 and 128 cpus, the potential saving will be 3 * 256 * 128 * 128 = 12MB. Acked-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20231222031750.1289290-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/memalloc.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index f71da07eb8a0..a8ee6fb8401c 100644
--- a/kernel/bpf/memalloc.c
+++ b/kernel/bpf/memalloc.c
@@ -485,11 +485,16 @@ static void init_refill_work(struct bpf_mem_cache *c)
static void prefill_mem_cache(struct bpf_mem_cache *c, int cpu)
{
- /* To avoid consuming memory assume that 1st run of bpf
- * prog won't be doing more than 4 map_update_elem from
- * irq disabled region
+ int cnt = 1;
+
+ /* To avoid consuming memory, for non-percpu allocation, assume that
+ * 1st run of bpf prog won't be doing more than 4 map_update_elem from
+ * irq disabled region if unit size is less than or equal to 256.
+ * For all other cases, let us just do one allocation.
*/
- alloc_bulk(c, c->unit_size <= 256 ? 4 : 1, cpu_to_node(cpu), false);
+ if (!c->percpu_size && c->unit_size <= 256)
+ cnt = 4;
+ alloc_bulk(c, cnt, cpu_to_node(cpu), false);
}
/* When size != 0 bpf_mem_cache for each cpu.