diff mbox series

[v4,22/22] lib/stackdepot: adjust DEPOT_POOLS_CAP for KMSAN

Message ID 301a115cf7ce8ddb42ef6de9151c2bb76ba728fc.1700502145.git.andreyknvl@google.com (mailing list archive)
State New
Headers show
Series stackdepot: allow evicting stack traces | expand

Commit Message

andrey.konovalov@linux.dev Nov. 20, 2023, 5:47 p.m. UTC 
From: Andrey Konovalov <andreyknvl@google.com>

KMSAN is frequently used in fuzzing scenarios and thus saves a lot of
stack traces. As KMSAN does not support evicting stack traces from the
stack depot, the stack depot capacity might be reached quickly with large
stack records.

Adjust the maximum number of stack depot pools for this case.

The average size of a stack trace saved into the stack depot is ~16
frames. Thus, adjust the maximum pools number accordingly to keep the
maximum number of stack traces that can be saved into the stack depot
similar to the one that was allowed before the stack trace eviction
changes.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/stackdepot.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index c1b31160f4b4..870cce2f4cbd 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -41,7 +41,17 @@ 
 #define DEPOT_OFFSET_BITS (DEPOT_POOL_ORDER + PAGE_SHIFT - DEPOT_STACK_ALIGN)
 #define DEPOT_POOL_INDEX_BITS (DEPOT_HANDLE_BITS - DEPOT_OFFSET_BITS - \
 			       STACK_DEPOT_EXTRA_BITS)
+#if IS_ENABLED(CONFIG_KMSAN) && CONFIG_STACKDEPOT_MAX_FRAMES >= 32
+/*
+ * KMSAN is frequently used in fuzzing scenarios and thus saves a lot of stack
+ * traces. As KMSAN does not support evicting stack traces from the stack
+ * depot, the stack depot capacity might be reached quickly with large stack
+ * records. Adjust the maximum number of stack depot pools for this case.
+ */
+#define DEPOT_POOLS_CAP (8192 * (CONFIG_STACKDEPOT_MAX_FRAMES / 16))
+#else
 #define DEPOT_POOLS_CAP 8192
+#endif
 #define DEPOT_MAX_POOLS \
 	(((1LL << (DEPOT_POOL_INDEX_BITS)) < DEPOT_POOLS_CAP) ? \
 	 (1LL << (DEPOT_POOL_INDEX_BITS)) : DEPOT_POOLS_CAP)