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| author | Liam R. Howlett <Liam.Howlett@Oracle.com> | 2022-09-06 19:48:45 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-09-26 19:46:14 -0700 |
| commit | d4af56c5c7c6781ca6ca8075e2cf5bc119ed33d1 (patch) | |
| tree | e3c5b2600a2a9231ab6bbb85ede7b2be92f637f9 /mm/init-mm.c | |
| parent | e15e06a8392321a19d8ebdbdd7643b7fa8874c17 (diff) | |
| download | lwn-d4af56c5c7c6781ca6ca8075e2cf5bc119ed33d1.tar.gz lwn-d4af56c5c7c6781ca6ca8075e2cf5bc119ed33d1.zip | |
mm: start tracking VMAs with maple tree
Start tracking the VMAs with the new maple tree structure in parallel with
the rb_tree. Add debug and trace events for maple tree operations and
duplicate the rb_tree that is created on forks into the maple tree.
The maple tree is added to the mm_struct including the mm_init struct,
added support in required mm/mmap functions, added tracking in kernel/fork
for process forking, and used to find the unmapped_area and checked
against what the rbtree finds.
This also moves the mmap_lock() in exit_mmap() since the oom reaper call
does walk the VMAs. Otherwise lockdep will be unhappy if oom happens.
When splitting a vma fails due to allocations of the maple tree nodes,
the error path in __split_vma() calls new->vm_ops->close(new). The page
accounting for hugetlb is actually in the close() operation, so it
accounts for the removal of 1/2 of the VMA which was not adjusted. This
results in a negative exit value. To avoid the negative charge, set
vm_start = vm_end and vm_pgoff = 0.
There is also a potential accounting issue in special mappings from
insert_vm_struct() failing to allocate, so reverse the charge there in
the failure scenario.
Link: https://lkml.kernel.org/r/20220906194824.2110408-9-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/init-mm.c')
| -rw-r--r-- | mm/init-mm.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/init-mm.c b/mm/init-mm.c index fbe7844d0912..b912b0f2eced 100644 --- a/mm/init-mm.c +++ b/mm/init-mm.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 #include <linux/mm_types.h> #include <linux/rbtree.h> +#include <linux/maple_tree.h> #include <linux/rwsem.h> #include <linux/spinlock.h> #include <linux/list.h> @@ -29,6 +30,7 @@ */ struct mm_struct init_mm = { .mm_rb = RB_ROOT, + .mm_mt = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, init_mm.mmap_lock), .pgd = swapper_pg_dir, .mm_users = ATOMIC_INIT(2), .mm_count = ATOMIC_INIT(1), |