Commit 5b95e638 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov

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: default avatarHou Tao <houtao1@huawei.com>
Signed-off-by: default avatarYonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20231222031750.1289290-1-yonghong.song@linux.devSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c39aa3b2
...@@ -485,11 +485,16 @@ static void init_refill_work(struct bpf_mem_cache *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) static void prefill_mem_cache(struct bpf_mem_cache *c, int cpu)
{ {
/* To avoid consuming memory assume that 1st run of bpf int cnt = 1;
* prog won't be doing more than 4 map_update_elem from
* irq disabled region /* 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. /* When size != 0 bpf_mem_cache for each cpu.
......
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