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| author | Marco Elver <elver@google.com> | 2024-01-29 11:07:01 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-02-23 17:27:12 -0800 |
| commit | 31639fd6cebd4fc3687cceda14814f140c9fd95b (patch) | |
| tree | 0d10f6a73f68ebe025722e17d134566bc554a864 /include/linux/poison.h | |
| parent | 2597c9947b0174fcc71bdd7ab6cb49c2b4291e95 (diff) | |
| download | linux-31639fd6cebd4fc3687cceda14814f140c9fd95b.tar.gz linux-31639fd6cebd4fc3687cceda14814f140c9fd95b.tar.bz2 linux-31639fd6cebd4fc3687cceda14814f140c9fd95b.zip | |
stackdepot: use variable size records for non-evictable entries
With the introduction of stack depot evictions, each stack record is now
fixed size, so that future reuse after an eviction can safely store
differently sized stack traces. In all cases that do not make use of
evictions, this wastes lots of space.
Fix it by re-introducing variable size stack records (up to the max
allowed size) for entries that will never be evicted. We know if an entry
will never be evicted if the flag STACK_DEPOT_FLAG_GET is not provided,
since a later stack_depot_put() attempt is undefined behavior.
With my current kernel config that enables KASAN and also SLUB owner
tracking, I observe (after a kernel boot) a whopping reduction of 296
stack depot pools, which translates into 4736 KiB saved. The savings here
are from SLUB owner tracking only, because KASAN generic mode still uses
refcounting.
Before:
pools: 893
allocations: 29841
frees: 6524
in_use: 23317
freelist_size: 3454
After:
pools: 597
refcounted_allocations: 17547
refcounted_frees: 6477
refcounted_in_use: 11070
freelist_size: 3497
persistent_count: 12163
persistent_bytes: 1717008
[elver@google.com: fix -Wstringop-overflow warning]
Link: https://lore.kernel.org/all/20240201135747.18eca98e@canb.auug.org.au/
Link: https://lkml.kernel.org/r/20240201090434.1762340-1-elver@google.com
Link: https://lore.kernel.org/all/CABXGCsOzpRPZGg23QqJAzKnqkZPKzvieeg=W7sgjgi3q0pBo0g@mail.gmail.com/
Link: https://lkml.kernel.org/r/20240129100708.39460-1-elver@google.com
Link: https://lore.kernel.org/all/CABXGCsOzpRPZGg23QqJAzKnqkZPKzvieeg=W7sgjgi3q0pBo0g@mail.gmail.com/
Fixes: 108be8def46e ("lib/stackdepot: allow users to evict stack traces")
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/poison.h')
| -rw-r--r-- | include/linux/poison.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/poison.h b/include/linux/poison.h index 27a7dad17eef..1f0ee2459f2a 100644 --- a/include/linux/poison.h +++ b/include/linux/poison.h @@ -92,4 +92,7 @@ /********** VFS **********/ #define VFS_PTR_POISON ((void *)(0xF5 + POISON_POINTER_DELTA)) +/********** lib/stackdepot.c **********/ +#define STACK_DEPOT_POISON ((void *)(0xD390 + POISON_POINTER_DELTA)) + #endif |