On Thu, Dec 26, 2024 at 5:09 PM Suren Baghdasaryan surenb@google.com wrote:
On Thu, Dec 26, 2024 at 5:07 PM Suren Baghdasaryan surenb@google.com wrote:
On Thu, Dec 26, 2024 at 4:43 PM Kent Overstreet kent.overstreet@linux.dev wrote:
On Thu, Dec 26, 2024 at 01:16:38PM -0800, Suren Baghdasaryan wrote:
When memory allocation profiling is disabled there is no need to update current->alloc_tag and these manipulations add unnecessary overhead. Fix the overhead by skipping these extra updates.
I did it the other way because I was concerned about the overhead of adding a huge number of static keys. But on further thought a static key probably isn't any bigger than an alloc tag, no?
Hmm but a call
Sorry, I pressed enter before finishing typing.
Is a call to static_branch_maybe() generate a new static key? I thought mem_alloc_profiling_key would be used everywhere but maybe I'm missing something?
Or maybe you meant the NoOp/Jump generated for a static_branch ?
Fixes: b951aaff5035 ("mm: enable page allocation tagging") Signed-off-by: Suren Baghdasaryan surenb@google.com Cc: stable@vger.kernel.org
include/linux/alloc_tag.h | 11 ++++++++--- lib/alloc_tag.c | 2 ++ 2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index 0bbbe537c5f9..a946e0203e6d 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -224,9 +224,14 @@ static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes) {}
#define alloc_hooks_tag(_tag, _do_alloc) \ ({ \
struct alloc_tag * __maybe_unused _old = alloc_tag_save(_tag); \typeof(_do_alloc) _res = _do_alloc; \alloc_tag_restore(_tag, _old); \
typeof(_do_alloc) _res; \if (mem_alloc_profiling_enabled()) { \struct alloc_tag * __maybe_unused _old; \_old = alloc_tag_save(_tag); \_res = _do_alloc; \alloc_tag_restore(_tag, _old); \} else \_res = _do_alloc; \ _res; \})
diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c index 7dcebf118a3e..4c373f444eb1 100644 --- a/lib/alloc_tag.c +++ b/lib/alloc_tag.c @@ -29,6 +29,8 @@ EXPORT_SYMBOL(_shared_alloc_tag);
DEFINE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT, mem_alloc_profiling_key); +EXPORT_SYMBOL(mem_alloc_profiling_key);
DEFINE_STATIC_KEY_FALSE(mem_profiling_compressed);
struct alloc_tag_kernel_section kernel_tags = { NULL, 0 };
base-commit: 431614f1580a03c1a653340c55ea76bd12a9403f
2.47.1.613.gc27f4b7a9f-goog