The patch titled
Subject: maple_tree: add mas_for_each_rev() helper
has been added to the -mm mm-unstable branch. Its filename is
maple_tree-add-mas_for_each_rev-helper.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/maple_tree-add-mas_for_each_rev-helper.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: maple_tree: add mas_for_each_rev() helper
Date: Wed, 23 Oct 2024 10:07:54 -0700
Patch series "page allocation tag compression", v4.
This patchset implements several improvements:
1. Gracefully handles module unloading while there are used
allocations allocated from that module;
2. Provides an option to store page allocation tag references in the
page flags, removing dependency on page extensions and eliminating the
memory overhead from storing page allocation references (~0.2% of total
system memory). This also improves page allocation performance when
CONFIG_MEM_ALLOC_PROFILING is enabled by eliminating page extension
lookup. Page allocation performance overhead is reduced from 41% to
5.5%.
Patch #1 introduces mas_for_each_rev() helper function.
Patch #2 introduces shutdown_mem_profiling() helper function to be used
when disabling memory allocation profiling.
Patch #3 copies module tags into virtually contiguous memory which
serves two purposes:
- Lets us deal with the situation when module is unloaded while there
are still live allocations from that module. Since we are using a copy
version of the tags we can safely unload the module. Space and gaps in
this contiguous memory are managed using a maple tree.
- Enables simple indexing of the tags in the later patches.
Patch #4 changes the way we allocate virtually contiguous memory for
module tags to reserve only vitrual area and populate physical pages only
as needed at module load time.
Patch #5 abstracts page allocation tag reference to simplify later
changes.
Patch #6 adds compression option to the sysctl.vm.mem_profiling boot
parameter for storing page allocation tag references inside page flags if
they fit. If the number of available page flag bits is insufficient to
address all kernel allocations, memory allocation profiling gets disabled
with an appropriate warning.
This patch (of 6):
Add mas_for_each_rev() function to iterate maple tree nodes in reverse
order.
Link: https://lkml.kernel.org/r/20241023170759.999909-1-surenb@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20241023170759.999909-2-surenb@xxxxxxxxxx
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Suggested-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Daniel Gomez <da.gomez@xxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Petr Pavlu <petr.pavlu@xxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Cc: Sourav Panda <souravpanda@xxxxxxxxxx>
Cc: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Thomas Huth <thuth@xxxxxxxxxx>
Cc: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Xiongwei Song <xiongwei.song@xxxxxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/maple_tree.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
--- a/include/linux/maple_tree.h~maple_tree-add-mas_for_each_rev-helper
+++ a/include/linux/maple_tree.h
@@ -592,6 +592,20 @@ static __always_inline void mas_reset(st
#define mas_for_each(__mas, __entry, __max) \
while (((__entry) = mas_find((__mas), (__max))) != NULL)
+/**
+ * mas_for_each_rev() - Iterate over a range of the maple tree in reverse order.
+ * @__mas: Maple Tree operation state (maple_state)
+ * @__entry: Entry retrieved from the tree
+ * @__min: minimum index to retrieve from the tree
+ *
+ * When returned, mas->index and mas->last will hold the entire range for the
+ * entry.
+ *
+ * Note: may return the zero entry.
+ */
+#define mas_for_each_rev(__mas, __entry, __min) \
+ while (((__entry) = mas_find_rev((__mas), (__min))) != NULL)
+
#ifdef CONFIG_DEBUG_MAPLE_TREE
enum mt_dump_format {
mt_dump_dec,
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
maple_tree-add-mas_for_each_rev-helper.patch
alloc_tag-introduce-shutdown_mem_profiling-helper-function.patch
alloc_tag-load-module-tags-into-separate-contiguous-memory.patch
alloc_tag-populate-memory-for-module-tags-as-needed.patch
alloc_tag-introduce-pgtag_ref_handle-to-abstract-page-tag-references.patch
alloc_tag-support-for-page-allocation-tag-compression.patch
