From c5665868183fec689dbab9fb8505188b2c4f0757 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Mon, 23 Sep 2019 15:34:05 -0700 Subject: mm: kmemleak: use the memory pool for early allocations Currently kmemleak uses a static early_log buffer to trace all memory allocation/freeing before the slab allocator is initialised. Such early log is replayed during kmemleak_init() to properly initialise the kmemleak metadata for objects allocated up that point. With a memory pool that does not rely on the slab allocator, it is possible to skip this early log entirely. In order to remove the early logging, consider kmemleak_enabled == 1 by default while the kmem_cache availability is checked directly on the object_cache and scan_area_cache variables. The RCU callback is only invoked after object_cache has been initialised as we wouldn't have any concurrent list traversal before this. In order to reduce the number of callbacks before kmemleak is fully initialised, move the kmemleak_init() call to mm_init(). [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: remove WARN_ON(), per Catalin] Link: http://lkml.kernel.org/r/20190812160642.52134-4-catalin.marinas@arm.com Signed-off-by: Catalin Marinas Cc: Matthew Wilcox Cc: Michal Hocko Cc: Qian Cai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig.debug | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 3c88e54da86c..c6975cded461 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -576,17 +576,18 @@ config DEBUG_KMEMLEAK In order to access the kmemleak file, debugfs needs to be mounted (usually at /sys/kernel/debug). -config DEBUG_KMEMLEAK_EARLY_LOG_SIZE - int "Maximum kmemleak early log entries" +config DEBUG_KMEMLEAK_MEM_POOL_SIZE + int "Kmemleak memory pool size" depends on DEBUG_KMEMLEAK range 200 40000 default 16000 help Kmemleak must track all the memory allocations to avoid reporting false positives. Since memory may be allocated or - freed before kmemleak is initialised, an early log buffer is - used to store these actions. If kmemleak reports "early log - buffer exceeded", please increase this value. + freed before kmemleak is fully initialised, use a static pool + of metadata objects to track such callbacks. After kmemleak is + fully initialised, this memory pool acts as an emergency one + if slab allocations fail. config DEBUG_KMEMLEAK_TEST tristate "Simple test for the kernel memory leak detector" -- cgit v1.2.3-58-ga151