From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,surenb@google.com,hao.ge@linux.dev,abhishekbapat@google.com,akpm@linux-foundation.org
Subject: [merged mm-stable] alloc_tag-expose-boot-time-compression-configuration.patch removed from -mm tree
Date: Mon, 24 Aug 2026 18:54:04 -0700 [thread overview]
Message-ID: <20260825015405.025501F00A3A@smtp.kernel.org> (raw)
The quilt patch titled
Subject: alloc_tag: expose boot-time compression configuration
has been removed from the -mm tree. Its filename was
alloc_tag-expose-boot-time-compression-configuration.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Abhishek Bapat <abhishekbapat@google.com>
Subject: alloc_tag: expose boot-time compression configuration
Date: Wed, 5 Aug 2026 17:29:52 +0000
Currently, userspace has limited visibility into the exact active runtime
state of memory allocation profiling and its page extension compression
('sysctl.vm.mem_profiling={0|1|never}[,compressed]').
While reading the sysctl provides basic on/off status, it is currently
impossible for userspace to natively determine whether page-tag
compression was successfully enabled without scraping dmesg boot logs.
Add a new read-only sysctl representing how compression was configured
at boot time.
Link: https://lore.kernel.org/c795f8089f82841e8a6e00d7ca286da2b23aeb7b.1785950530.git.abhishekbapat@google.com
Signed-off-by: Abhishek Bapat <abhishekbapat@google.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Hao Ge <hao.ge@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
Documentation/mm/allocation-profiling.rst | 11 +++++++++++
mm/alloc_tag.c | 6 ++++++
2 files changed, 17 insertions(+)
--- a/Documentation/mm/allocation-profiling.rst~alloc_tag-expose-boot-time-compression-configuration
+++ a/Documentation/mm/allocation-profiling.rst
@@ -43,6 +43,17 @@ sysctl:
warnings produced by allocations made while profiling is disabled and freed
when it's enabled.
+ /proc/sys/vm/mem_profiling_compressed
+
+ 1: Page alloc tag compression is enabled.
+
+ 0: Page alloc tag compression is disabled.
+
+ This reflects a static boot-time configuration of how page allocation tags are
+ stored (in page flags when compression is enabled and in page_ext when disabled).
+ Toggling ``mem_profiling`` at runtime does not change the state of
+ ``mem_profiling_compressed``.
+
Runtime info:
/proc/allocinfo
--- a/mm/alloc_tag.c~alloc_tag-expose-boot-time-compression-configuration
+++ a/mm/alloc_tag.c
@@ -961,6 +961,12 @@ static const struct ctl_table memory_all
.mode = 0644,
.proc_handler = proc_mem_profiling_handler,
},
+ {
+ .procname = "mem_profiling_compressed",
+ .data = &mem_profiling_compressed,
+ .mode = 0444,
+ .proc_handler = proc_do_static_key,
+ },
};
static void __init sysctl_init(void)
_
Patches currently in -mm which might be from abhishekbapat@google.com are
reply other threads:[~2026-08-25 1:54 UTC|newest]
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