diff mbox series

[bpf,2/4] bpf: Don't prefill for unused bpf_mem_cache

Message ID 20230908133923.2675053-3-houtao@huaweicloud.com (mailing list archive)
State Accepted
Commit b1d53958b69312e43c118d4093d8f93d3f6f80af
Delegated to: BPF
Headers show
Series Fix the unmatched unit_size of bpf_mem_cache | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1345 this patch: 1345
netdev/cc_maintainers success CCed 12 of 12 maintainers
netdev/build_clang success Errors and warnings before: 1364 this patch: 1364
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1368 this patch: 1368
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 41 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-PR success PR summary
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Commit Message

Hou Tao Sept. 8, 2023, 1:39 p.m. UTC 
From: Hou Tao <houtao1@huawei.com>

When the unit_size of a bpf_mem_cache is unmatched with the object_size
of the underlying slab cache, the bpf_mem_cache will not be used, and
the allocation will be redirected to a bpf_mem_cache with a bigger
unit_size instead, so there is no need to prefill for these
unused bpf_mem_caches.

Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 kernel/bpf/memalloc.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index 98d9e96fba3c..90c1ed8210a2 100644
--- a/kernel/bpf/memalloc.c
+++ b/kernel/bpf/memalloc.c
@@ -459,8 +459,7 @@  static void notrace irq_work_raise(struct bpf_mem_cache *c)
  * Typical case will be between 11K and 116K closer to 11K.
  * bpf progs can and should share bpf_mem_cache when possible.
  */
-
-static void prefill_mem_cache(struct bpf_mem_cache *c, int cpu)
+static void init_refill_work(struct bpf_mem_cache *c)
 {
 	init_irq_work(&c->refill_work, bpf_mem_refill);
 	if (c->unit_size <= 256) {
@@ -476,7 +475,10 @@  static void prefill_mem_cache(struct bpf_mem_cache *c, int cpu)
 		c->high_watermark = max(96 * 256 / c->unit_size, 3);
 	}
 	c->batch = max((c->high_watermark - c->low_watermark) / 4 * 3, 1);
+}
 
+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
@@ -521,6 +523,7 @@  int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu)
 			c->objcg = objcg;
 			c->percpu_size = percpu_size;
 			c->tgt = c;
+			init_refill_work(c);
 			prefill_mem_cache(c, cpu);
 		}
 		ma->cache = pc;
@@ -544,6 +547,15 @@  int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu)
 			c->unit_size = sizes[i];
 			c->objcg = objcg;
 			c->tgt = c;
+
+			init_refill_work(c);
+			/* Another bpf_mem_cache will be used when allocating
+			 * c->unit_size in bpf_mem_alloc(), so doesn't prefill
+			 * for the bpf_mem_cache because these free objects will
+			 * never be used.
+			 */
+			if (i != bpf_mem_cache_idx(c->unit_size))
+				continue;
 			prefill_mem_cache(c, cpu);
 		}
 	}