Patch series "Refactor of vma_merge and new merge call", v4.
I am currently working on my master's thesis trying to increase number of
merges of VMAs currently failing because of page offset incompatibility
and difference in their anon_vmas. The following refactor and added merge
call included in this series is just two smaller upgrades I created along
the way.
This patch (of 2):
Refactor vma_merge() to make it shorter and more understandable. Main
change is the elimination of code duplicity in the case of merge next
check. This is done by first doing checks and caching the results before
executing the merge itself. The variable 'area' is divided into 'mid' and
'res' as previously it was used for two purposes, as the middle VMA
between prev and next and also as the result of the merge itself. Exit
paths are also unified.
Link: https://lkml.kernel.org/r/20220603145719.1012094-1-matenajakub@gmail.com
Link: https://lkml.kernel.org/r/20220603145719.1012094-2-matenajakub@gmail.com
Signed-off-by: Jakub Matěna <matenajakub@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Rik van Riel <riel@surriel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With the last usage of MMF_OOM_VICTIM in exit_mmap gone, this flag is now
unused and can be removed.
[akpm@linux-foundation.org: remove comment about now-removed mm_is_oom_victim()]
Link: https://lkml.kernel.org/r/20220531223100.510392-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christian Brauner (Microsoft) <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The primary reason to invoke the oom reaper from the exit_mmap path used
to be a prevention of an excessive oom killing if the oom victim exit
races with the oom reaper (see [1] for more details). The invocation has
moved around since then because of the interaction with the munlock logic
but the underlying reason has remained the same (see [2]).
Munlock code is no longer a problem since [3] and there shouldn't be any
blocking operation before the memory is unmapped by exit_mmap so the oom
reaper invocation can be dropped. The unmapping part can be done with the
non-exclusive mmap_sem and the exclusive one is only required when page
tables are freed.
Remove the oom_reaper from exit_mmap which will make the code easier to
read. This is really unlikely to make any observable difference although
some microbenchmarks could benefit from one less branch that needs to be
evaluated even though it almost never is true.
[1] 2129258024 ("mm: oom: let oom_reap_task and exit_mmap run concurrently")
[2] 27ae357fa8 ("mm, oom: fix concurrent munlock and oom reaper unmap, v3")
[3] a213e5cf71 ("mm/munlock: delete munlock_vma_pages_all(), allow oomreap")
[akpm@linux-foundation.org: restore Suren's mmap_read_lock() optimization]
Link: https://lkml.kernel.org/r/20220531223100.510392-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christian Brauner (Microsoft) <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
__vma_link_file() resolves the mapping from the file, if there is one.
Pass through the mapping and check the vm_file externally since most
places already have the required information and check of vm_file.
Link: https://lkml.kernel.org/r/20220906194824.2110408-71-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
Since there is no longer a linked list, the range_has_overlap() function
is identical to the find_vma_intersection() function.
Link: https://lkml.kernel.org/r/20220906194824.2110408-70-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace any vm_next use with vma_find().
Update free_pgtables(), unmap_vmas(), and zap_page_range() to use the
maple tree.
Use the new free_pgtables() and unmap_vmas() in do_mas_align_munmap(). At
the same time, alter the loop to be more compact.
Now that free_pgtables() and unmap_vmas() take a maple tree as an
argument, rearrange do_mas_align_munmap() to use the new tree to hold the
vmas to remove.
Remove __vma_link_list() and __vma_unlink_list() as they are exclusively
used to update the linked list.
Drop linked list update from __insert_vm_struct().
Rework validation of tree as it was depending on the linked list.
[yang.lee@linux.alibaba.com: fix one kernel-doc comment]
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=1949
Link: https://lkml.kernel.org/r/20220824021918.94116-1-yang.lee@linux.alibaba.comLink: https://lkml.kernel.org/r/20220906194824.2110408-69-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
Don't use the mm_struct linked list or the vma->vm_next in prep for
removal.
Link: https://lkml.kernel.org/r/20220906194824.2110408-45-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
do_brk_munmap() has already aligned the address and has a maple tree state
to be used. Use the new do_mas_align_munmap() to avoid unnecessary
alignment and error checks.
Link: https://lkml.kernel.org/r/20220906194824.2110408-30-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
Remove __do_munmap() in favour of do_munmap(), do_mas_munmap(), and
do_mas_align_munmap().
do_munmap() is a wrapper to create a maple state for any callers that have
not been converted to the maple tree.
do_mas_munmap() takes a maple state to mumap a range. This is just a
small function which checks for error conditions and aligns the end of the
range.
do_mas_align_munmap() uses the aligned range to mumap a range.
do_mas_align_munmap() starts with the first VMA in the range, then finds
the last VMA in the range. Both start and end are split if necessary.
Then the VMAs are removed from the linked list and the mm mlock count is
updated at the same time. Followed by a single tree operation of
overwriting the area in with a NULL. Finally, the detached list is
unmapped and freed.
By reorganizing the munmap calls as outlined, it is now possible to avoid
extra work of aligning pre-aligned callers which are known to be safe,
avoid extra VMA lookups or tree walks for modifications.
detach_vmas_to_be_unmapped() is no longer used, so drop this code.
vm_brk_flags() can just call the do_mas_munmap() as it checks for
intersecting VMAs directly.
Link: https://lkml.kernel.org/r/20220906194824.2110408-29-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
Relocation of code for the next commit. There should be no changes here.
Link: https://lkml.kernel.org/r/20220906194824.2110408-28-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
By using the maple tree and the maple tree state, the vmacache is no
longer beneficial and is complicating the VMA code. Remove the vmacache
to reduce the work in keeping it up to date and code complexity.
Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Changing mmap_region() to use the maple tree state and the advanced maple
tree interface allows for a lot less tree walking.
This change removes the last caller of munmap_vma_range(), so drop this
unused function.
Add vma_expand() to expand a VMA if possible by doing the necessary
hugepage check, uprobe_munmap of files, dcache flush, modifications then
undoing the detaches, etc.
Link: https://lkml.kernel.org/r/20220906194824.2110408-25-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
Move find_vma_intersection() to mmap.c and change implementation to maple
tree.
When searching for a vma within a range, it is easier to use the maple
tree interface.
Exported find_vma_intersection() for kvm module.
Link: https://lkml.kernel.org/r/20220906194824.2110408-24-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
Avoid allocating a new VMA when it a vma modification can occur. When a
brk() can expand or contract a VMA, then the single store operation will
only modify one index of the maple tree instead of causing a node to split
or coalesce. This avoids unnecessary allocations/frees of maple tree
nodes and VMAs.
Move some limit & flag verifications out of the do_brk_flags() function to
use only relevant checks in the code path of bkr() and vm_brk_flags().
Set the vma to check if it can expand in vm_brk_flags() if extra criteria
are met.
Drop userfaultfd from do_brk_flags() path and only use it in
vm_brk_flags() path since that is the only place a munmap will happen.
Add a wraper for munmap for the brk case called do_brk_munmap().
Link: https://lkml.kernel.org/r/20220906194824.2110408-23-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
Only write to the maple tree if we are not inserting or the insert isn't
going to overwrite the area to clear. This avoids spanning writes and
node coealescing when unnecessary.
The change requires a custom search for the linked list addition to find
the correct VMA for the prev link.
Link: https://lkml.kernel.org/r/20220906194824.2110408-19-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
Remove the RB tree and start using the maple tree for vm_area_struct
tracking.
Drop validate_mm() calls in expand_upwards() and expand_downwards() as the
lock is not held.
Link: https://lkml.kernel.org/r/20220906194824.2110408-18-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
The maple tree code was added to find the unmapped area in a previous
commit and was checked against what the rbtree returned, but the actual
result was never used. Start using the maple tree implementation and
remove the rbtree code.
Add kernel documentation comment for these functions.
Link: https://lkml.kernel.org/r/20220906194824.2110408-14-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
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>
Use the maple tree's advanced API and a maple state to walk the tree for
the entry at the address of the next vma, then use the maple state to walk
back one entry to find the previous entry.
Add kernel documentation comments for this API.
Link: https://lkml.kernel.org/r/20220906194824.2110408-13-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.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: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Using the maple tree interface mt_find() will handle the RCU locking and
will start searching at the address up to the limit, ULONG_MAX in this
case.
Add kernel documentation to this API.
Link: https://lkml.kernel.org/r/20220906194824.2110408-12-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This simplifies the implementation and is faster than using the linked
list.
Link: https://lkml.kernel.org/r/20220906194824.2110408-11-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This thin layer of abstraction over the maple tree state is for iterating
over VMAs. You can go forwards, go backwards or ask where the iterator
is. Rename the existing vma_next() to __vma_next() -- it will be removed
by the end of this series.
Link: https://lkml.kernel.org/r/20220906194824.2110408-10-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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>
Align larger anonymous memory mappings on THP boundaries by going through
thp_get_unmapped_area if THPs are enabled for the current process.
With this patch, larger anonymous mappings are now THP aligned. When a
malloc library allocates a 2MB or larger arena, that arena can now be
mapped with THPs right from the start, which can result in better TLB hit
rates and execution time.
Link: https://lkml.kernel.org/r/20220809142457.4751229f@imladris.surriel.com
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/hugetlb: fix write-fault handling for shared mappings", v2.
I observed that hugetlb does not support/expect write-faults in shared
mappings that would have to map the R/O-mapped page writable -- and I
found two case where we could currently get such faults and would
erroneously map an anon page into a shared mapping.
Reproducers part of the patches.
I propose to backport both fixes to stable trees. The first fix needs a
small adjustment.
This patch (of 2):
Staring at hugetlb_wp(), one might wonder where all the logic for shared
mappings is when stumbling over a write-protected page in a shared
mapping. In fact, there is none, and so far we thought we could get away
with that because e.g., mprotect() should always do the right thing and
map all pages directly writable.
Looks like we were wrong:
--------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
#define HUGETLB_SIZE (2 * 1024 * 1024u)
static void clear_softdirty(void)
{
int fd = open("/proc/self/clear_refs", O_WRONLY);
const char *ctrl = "4";
int ret;
if (fd < 0) {
fprintf(stderr, "open(clear_refs) failed\n");
exit(1);
}
ret = write(fd, ctrl, strlen(ctrl));
if (ret != strlen(ctrl)) {
fprintf(stderr, "write(clear_refs) failed\n");
exit(1);
}
close(fd);
}
int main(int argc, char **argv)
{
char *map;
int fd;
fd = open("/dev/hugepages/tmp", O_RDWR | O_CREAT);
if (!fd) {
fprintf(stderr, "open() failed\n");
return -errno;
}
if (ftruncate(fd, HUGETLB_SIZE)) {
fprintf(stderr, "ftruncate() failed\n");
return -errno;
}
map = mmap(NULL, HUGETLB_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (map == MAP_FAILED) {
fprintf(stderr, "mmap() failed\n");
return -errno;
}
*map = 0;
if (mprotect(map, HUGETLB_SIZE, PROT_READ)) {
fprintf(stderr, "mmprotect() failed\n");
return -errno;
}
clear_softdirty();
if (mprotect(map, HUGETLB_SIZE, PROT_READ|PROT_WRITE)) {
fprintf(stderr, "mmprotect() failed\n");
return -errno;
}
*map = 0;
return 0;
}
--------------------------------------------------------------------------
Above test fails with SIGBUS when there is only a single free hugetlb page.
# echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
# ./test
Bus error (core dumped)
And worse, with sufficient free hugetlb pages it will map an anonymous page
into a shared mapping, for example, messing up accounting during unmap
and breaking MAP_SHARED semantics:
# echo 2 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
# ./test
# cat /proc/meminfo | grep HugePages_
HugePages_Total: 2
HugePages_Free: 1
HugePages_Rsvd: 18446744073709551615
HugePages_Surp: 0
Reason in this particular case is that vma_wants_writenotify() will
return "true", removing VM_SHARED in vma_set_page_prot() to map pages
write-protected. Let's teach vma_wants_writenotify() that hugetlb does not
support softdirty tracking.
Link: https://lkml.kernel.org/r/20220811103435.188481-1-david@redhat.com
Link: https://lkml.kernel.org/r/20220811103435.188481-2-david@redhat.com
Fixes: 64e455079e ("mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org> [3.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/mprotect: Fix soft-dirty checks", v4.
This patch (of 3):
The check wanted to make sure when soft-dirty tracking is enabled we won't
grant write bit by accident, as a page fault is needed for dirty tracking.
The intention is correct but we didn't check it right because
VM_SOFTDIRTY set actually means soft-dirty tracking disabled. Fix it.
There's another thing tricky about soft-dirty is that, we can't check the
vma flag !(vma_flags & VM_SOFTDIRTY) directly but only check it after we
checked CONFIG_MEM_SOFT_DIRTY because otherwise VM_SOFTDIRTY will be
defined as zero, and !(vma_flags & VM_SOFTDIRTY) will constantly return
true. To avoid misuse, introduce a helper for checking whether vma has
soft-dirty tracking enabled.
We can easily verify this with any exclusive anonymous page, like program
below:
=======8<======
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <inttypes.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdbool.h>
#define BIT_ULL(nr) (1ULL << (nr))
#define PM_SOFT_DIRTY BIT_ULL(55)
unsigned int psize;
char *page;
uint64_t pagemap_read_vaddr(int fd, void *vaddr)
{
uint64_t value;
int ret;
ret = pread(fd, &value, sizeof(uint64_t),
((uint64_t)vaddr >> 12) * sizeof(uint64_t));
assert(ret == sizeof(uint64_t));
return value;
}
void clear_refs_write(void)
{
int fd = open("/proc/self/clear_refs", O_RDWR);
assert(fd >= 0);
write(fd, "4", 2);
close(fd);
}
#define check_soft_dirty(str, expect) do { \
bool dirty = pagemap_read_vaddr(fd, page) & PM_SOFT_DIRTY; \
if (dirty != expect) { \
printf("ERROR: %s, soft-dirty=%d (expect: %d)
", str, dirty, expect); \
exit(-1); \
} \
} while (0)
int main(void)
{
int fd = open("/proc/self/pagemap", O_RDONLY);
assert(fd >= 0);
psize = getpagesize();
page = mmap(NULL, psize, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
assert(page != MAP_FAILED);
*page = 1;
check_soft_dirty("Just faulted in page", 1);
clear_refs_write();
check_soft_dirty("Clear_refs written", 0);
mprotect(page, psize, PROT_READ);
check_soft_dirty("Marked RO", 0);
mprotect(page, psize, PROT_READ|PROT_WRITE);
check_soft_dirty("Marked RW", 0);
*page = 2;
check_soft_dirty("Wrote page again", 1);
munmap(page, psize);
close(fd);
printf("Test passed.
");
return 0;
}
=======8<======
Here we attach a Fixes to commit 64fe24a3e0 only for easy tracking, as
this patch won't apply to a tree before that point. However the commit
wasn't the source of problem, but instead 64e455079e. It's just that
after 64fe24a3e0 anonymous memory will also suffer from this problem
with mprotect().
Link: https://lkml.kernel.org/r/20220725142048.30450-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20220725142048.30450-2-peterx@redhat.com
Fixes: 64e455079e ("mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared")
Fixes: 64fe24a3e0 ("mm/mprotect: try avoiding write faults for exclusive anonymous pages when changing protection")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since the beginning, charged is set to 0 to avoid calling vm_unacct_memory
twice because vm_unacct_memory will be called by above unmap_region. But
since commit 4f74d2c8e8 ("vm: remove 'nr_accounted' calculations from
the unmap_vmas() interfaces"), unmap_region doesn't call vm_unacct_memory
anymore. So charged shouldn't be set to 0 now otherwise the calling to
paired vm_unacct_memory will be missed and leads to imbalanced account.
Link: https://lkml.kernel.org/r/20220618082027.43391-1-linmiaohe@huawei.com
Fixes: 4f74d2c8e8 ("vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mmget_still_valid() has already been removed via commit 4d45e75a99 ("mm:
remove the now-unnecessary mmget_still_valid() hack"). Update the
corresponding comment.
Link: https://lkml.kernel.org/r/20220709092527.47778-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Now all the platforms enable ARCH_HAS_GET_PAGE_PROT. They define and
export own vm_get_page_prot() whether custom or standard
DECLARE_VM_GET_PAGE_PROT. Hence there is no need for default generic
fallback for vm_get_page_prot(). Just drop this fallback and also
ARCH_HAS_GET_PAGE_PROT mechanism.
Link: https://lkml.kernel.org/r/20220711070600.2378316-27-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This just converts the generic vm_get_page_prot() implementation into a
new macro i.e DECLARE_VM_GET_PAGE_PROT which later can be used across
platforms when enabling them with ARCH_HAS_VM_GET_PAGE_PROT. This does
not create any functional change.
Link: https://lkml.kernel.org/r/20220711070600.2378316-3-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/mmap: Drop __SXXX/__PXXX macros from across platforms",
v7.
__SXXX/__PXXX macros are unnecessary abstraction layer in creating the
generic protection_map[] array which is used for vm_get_page_prot(). This
abstraction layer can be avoided, if the platforms just define the array
protection_map[] for all possible vm_flags access permission combinations
and also export vm_get_page_prot() implementation.
This series drops __SXXX/__PXXX macros from across platforms in the tree.
First it build protects generic protection_map[] array with '#ifdef
__P000' and moves it inside platforms which enable
ARCH_HAS_VM_GET_PAGE_PROT. Later this build protects same array with
'#ifdef ARCH_HAS_VM_GET_PAGE_PROT' and moves inside remaining platforms
while enabling ARCH_HAS_VM_GET_PAGE_PROT. This adds a new macro
DECLARE_VM_GET_PAGE_PROT defining the current generic vm_get_page_prot(),
in order for it to be reused on platforms that do not require custom
implementation. Finally, ARCH_HAS_VM_GET_PAGE_PROT can just be dropped,
as all platforms now define and export vm_get_page_prot(), via looking up
a private and static protection_map[] array. protection_map[] data type
has been changed as 'static const' on all platforms that do not change it
during boot.
This patch (of 26):
Build protect generic protection_map[] array with __P000, so that it can
be moved inside all the platforms one after the other. Otherwise there
will be build failures during this process.
CONFIG_ARCH_HAS_VM_GET_PAGE_PROT cannot be used for this purpose as only
certain platforms enable this config now.
Link: https://lkml.kernel.org/r/20220711070600.2378316-1-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/20220711070600.2378316-2-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
so it will be consistent with code mm directory and with
Documentation/admin-guide/mm and won't be confused with virtual machines.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Wu XiangCheng <bobwxc@email.cn>
- Convert to the generic mmap support (ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT).
- Add support for outline-only KASAN with 64-bit Radix MMU (P9 or later).
- Increase SIGSTKSZ and MINSIGSTKSZ and add support for AT_MINSIGSTKSZ.
- Enable the DAWR (Data Address Watchpoint) on POWER9 DD2.3 or later.
- Drop support for system call instruction emulation.
- Many other small features and fixes.
Thanks to: Alexey Kardashevskiy, Alistair Popple, Andy Shevchenko, Bagas Sanjaya, Bjorn
Helgaas, Bo Liu, Chen Huang, Christophe Leroy, Colin Ian King, Daniel Axtens, Dwaipayan
Ray, Fabiano Rosas, Finn Thain, Frank Rowand, Fuqian Huang, Guilherme G. Piccoli, Hangyu
Hua, Haowen Bai, Haren Myneni, Hari Bathini, He Ying, Jason Wang, Jiapeng Chong, Jing
Yangyang, Joel Stanley, Julia Lawall, Kajol Jain, Kevin Hao, Krzysztof Kozlowski, Laurent
Dufour, Lv Ruyi, Madhavan Srinivasan, Magali Lemes, Miaoqian Lin, Minghao Chi, Nathan
Chancellor, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Oscar Salvador, Pali Rohár,
Paul Mackerras, Peng Wu, Qing Wang, Randy Dunlap, Reza Arbab, Russell Currey, Sohaib
Mohamed, Vaibhav Jain, Vasant Hegde, Wang Qing, Wang Wensheng, Xiang wangx, Xiaomeng Tong,
Xu Wang, Yang Guang, Yang Li, Ye Bin, YueHaibing, Yu Kuai, Zheng Bin, Zou Wei, Zucheng
Zheng.
-----BEGIN PGP SIGNATURE-----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=15oQ
-----END PGP SIGNATURE-----
Merge tag 'powerpc-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Convert to the generic mmap support (ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
- Add support for outline-only KASAN with 64-bit Radix MMU (P9 or later)
- Increase SIGSTKSZ and MINSIGSTKSZ and add support for AT_MINSIGSTKSZ
- Enable the DAWR (Data Address Watchpoint) on POWER9 DD2.3 or later
- Drop support for system call instruction emulation
- Many other small features and fixes
Thanks to Alexey Kardashevskiy, Alistair Popple, Andy Shevchenko, Bagas
Sanjaya, Bjorn Helgaas, Bo Liu, Chen Huang, Christophe Leroy, Colin Ian
King, Daniel Axtens, Dwaipayan Ray, Fabiano Rosas, Finn Thain, Frank
Rowand, Fuqian Huang, Guilherme G. Piccoli, Hangyu Hua, Haowen Bai,
Haren Myneni, Hari Bathini, He Ying, Jason Wang, Jiapeng Chong, Jing
Yangyang, Joel Stanley, Julia Lawall, Kajol Jain, Kevin Hao, Krzysztof
Kozlowski, Laurent Dufour, Lv Ruyi, Madhavan Srinivasan, Magali Lemes,
Miaoqian Lin, Minghao Chi, Nathan Chancellor, Naveen N. Rao, Nicholas
Piggin, Oliver O'Halloran, Oscar Salvador, Pali Rohár, Paul Mackerras,
Peng Wu, Qing Wang, Randy Dunlap, Reza Arbab, Russell Currey, Sohaib
Mohamed, Vaibhav Jain, Vasant Hegde, Wang Qing, Wang Wensheng, Xiang
wangx, Xiaomeng Tong, Xu Wang, Yang Guang, Yang Li, Ye Bin, YueHaibing,
Yu Kuai, Zheng Bin, Zou Wei, and Zucheng Zheng.
* tag 'powerpc-5.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (200 commits)
powerpc/64: Include cache.h directly in paca.h
powerpc/64s: Only set HAVE_ARCH_UNMAPPED_AREA when CONFIG_PPC_64S_HASH_MMU is set
powerpc/xics: Include missing header
powerpc/powernv/pci: Drop VF MPS fixup
powerpc/fsl_book3e: Don't set rodata RO too early
powerpc/microwatt: Add mmu bits to device tree
powerpc/powernv/flash: Check OPAL flash calls exist before using
powerpc/powermac: constify device_node in of_irq_parse_oldworld()
powerpc/powermac: add missing g5_phy_disable_cpu1() declaration
selftests/powerpc/pmu: fix spelling mistake "mis-match" -> "mismatch"
powerpc: Enable the DAWR on POWER9 DD2.3 and above
powerpc/64s: Add CPU_FTRS_POWER10 to ALWAYS mask
powerpc/64s: Add CPU_FTRS_POWER9_DD2_2 to CPU_FTRS_ALWAYS mask
powerpc: Fix all occurences of "the the"
selftests/powerpc/pmu/ebb: remove fixed_instruction.S
powerpc/platforms/83xx: Use of_device_get_match_data()
powerpc/eeh: Drop redundant spinlock initialization
powerpc/iommu: Add missing of_node_put in iommu_init_early_dart
powerpc/pseries/vas: Call misc_deregister if sysfs init fails
powerpc/papr_scm: Fix leaking nvdimm_events_map elements
...
The readonly FS THP relies on khugepaged to collapse THP for suitable
vmas. But the behavior is inconsistent for "always" mode
(https://lore.kernel.org/linux-mm/00f195d4-d039-3cf2-d3a1-a2c88de397a0@suse.cz/).
The "always" mode means THP allocation should be tried all the time and
khugepaged should try to collapse THP all the time. Of course the
allocation and collapse may fail due to other factors and conditions.
Currently file THP may not be collapsed by khugepaged even though all the
conditions are met. That does break the semantics of "always" mode.
So make sure readonly FS vmas are registered to khugepaged to fix the
break.
Register suitable vmas in common mmap path, that could cover both readonly
FS vmas and shmem vmas, so remove the khugepaged calls in shmem.c.
Still need to keep the khugepaged call in vma_merge() since vma_merge() is
called in a lot of places, for example, madvise, mprotect, etc.
Link: https://lkml.kernel.org/r/20220510203222.24246-9-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastmil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Song Liu <song@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The khugepaged_enter_vma_merge() actually does as the same thing as the
khugepaged_enter() section called by shmem_mmap(), so consolidate them
into one helper and rename it to khugepaged_enter_vma().
Link: https://lkml.kernel.org/r/20220510203222.24246-8-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastmil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <song@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit c1e8d7c6a7 ("mmap locking API: convert mmap_sem comments") missed
replacing some references of mmap_sem by mmap_lock due to misspelling
(mm_sem instead of mmap_sem).
Link: https://lkml.kernel.org/r/20220503113333.214124-1-mail@florommel.de
Signed-off-by: Florian Rommel <mail@florommel.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Powerpc needs flags and len to make decision on arch_get_mmap_end().
So add them as parameters to arch_get_mmap_end().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b556daabe7d2bdb2361c4d6130280da7c1ba2c14.1649523076.git.christophe.leroy@csgroup.eu
Unlike most architectures, powerpc can only define at runtime
if it is going to use the generic arch_get_unmapped_area() or not.
Today, powerpc has a copy of the generic arch_get_unmapped_area()
because when selection HAVE_ARCH_UNMAPPED_AREA the generic
arch_get_unmapped_area() is not available.
Rename it generic_get_unmapped_area() and make it independent of
HAVE_ARCH_UNMAPPED_AREA.
Do the same for arch_get_unmapped_area_topdown() versus
HAVE_ARCH_UNMAPPED_AREA_TOPDOWN.
Do the same for hugetlb_get_unmapped_area() versus
HAVE_ARCH_HUGETLB_UNMAPPED_AREA.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/77f9d3e592f1c8511df9381aa1c4e754651da4d1.1649523076.git.christophe.leroy@csgroup.eu
There are no platforms left which use arch_vm_get_page_prot(). Just drop
generic arch_vm_get_page_prot().
Link: https://lkml.kernel.org/r/20220414062125.609297-8-anshuman.khandual@arm.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There are no platforms left which subscribe ARCH_HAS_FILTER_PGPROT. Hence
drop generic arch_filter_pgprot() and also config ARCH_HAS_FILTER_PGPROT.
Link: https://lkml.kernel.org/r/20220414062125.609297-7-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/mmap: Drop arch_vm_get_page_prot() and arch_filter_pgprot()", v7.
protection_map[] is an array based construct that translates given
vm_flags combination. This array contains page protection map, which is
populated by the platform via [__S000 .. __S111] and [__P000 .. __P111]
exported macros. Primary usage for protection_map[] is for
vm_get_page_prot(), which is used to determine page protection value for a
given vm_flags. vm_get_page_prot() implementation, could again call
platform overrides arch_vm_get_page_prot() and arch_filter_pgprot(). Some
platforms override protection_map[] that was originally built with
__SXXX/__PXXX with different runtime values.
Currently there are multiple layers of abstraction i.e __SXXX/__PXXX
macros , protection_map[], arch_vm_get_page_prot() and
arch_filter_pgprot() built between the platform and generic MM, finally
defining vm_get_page_prot().
Hence this series proposes to drop later two abstraction levels and
instead just move the responsibility of defining vm_get_page_prot() to the
platform (still utilizing generic protection_map[] array) itself making it
clean and simple.
This first introduces ARCH_HAS_VM_GET_PAGE_PROT which enables the
platforms to define custom vm_get_page_prot(). This starts converting
platforms that define the overrides arch_filter_pgprot() or
arch_vm_get_page_prot() which enables for those constructs to be dropped
off completely.
The series has been inspired from an earlier discuss with Christoph Hellwig
https://lore.kernel.org/all/1632712920-8171-1-git-send-email-anshuman.khandual@arm.com/
This patch (of 7):
Add a new config ARCH_HAS_VM_GET_PAGE_PROT, which when subscribed enables
a given platform to define its own vm_get_page_prot() but still utilizing
the generic protection_map[] array.
Link: https://lkml.kernel.org/r/20220414062125.609297-1-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/20220414062125.609297-2-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use helper mlock_future_check() to check whether it's safe to enlarge the
locked_vm to simplify the code. Minor readability improvement.
Link: https://lkml.kernel.org/r/20220402032231.64974-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
protection_map[] maps vm_flags access combinations into page protection
value as defined by the platform via __PXXX and __SXXX macros. The array
indices in protection_map[], represents vm_flags access combinations but
it's not very intuitive to derive. This makes it clear and explicit.
Link: https://lkml.kernel.org/r/20220404031840.588321-3-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In case the lock is actually not held at this point.
Link: https://lkml.kernel.org/r/5827758.TJ1SttVevJ@mobilepool36.emlix.com
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This is a fix for commit f6795053da ("mm: mmap: Allow for "high"
userspace addresses") for hugetlb.
This patch adds support for "high" userspace addresses that are
optionally supported on the system and have to be requested via a hint
mechanism ("high" addr parameter to mmap).
Architectures such as powerpc and x86 achieve this by making changes to
their architectural versions of hugetlb_get_unmapped_area() function.
However, arm64 uses the generic version of that function.
So take into account arch_get_mmap_base() and arch_get_mmap_end() in
hugetlb_get_unmapped_area(). To allow that, move those two macros out
of mm/mmap.c into include/linux/sched/mm.h
If these macros are not defined in architectural code then they default
to (TASK_SIZE) and (base) so should not introduce any behavioural
changes to architectures that do not define them.
For the time being, only ARM64 is affected by this change.
Catalin (ARM64) said
"We should have fixed hugetlb_get_unmapped_area() as well when we added
support for 52-bit VA. The reason for commit f6795053da was to
prevent normal mmap() from returning addresses above 48-bit by default
as some user-space had hard assumptions about this.
It's a slight ABI change if you do this for hugetlb_get_unmapped_area()
but I doubt anyone would notice. It's more likely that the current
behaviour would cause issues, so I'd rather have them consistent.
Basically when arm64 gained support for 52-bit addresses we did not
want user-space calling mmap() to suddenly get such high addresses,
otherwise we could have inadvertently broken some programs (similar
behaviour to x86 here). Hence we added commit f6795053da. But we
missed hugetlbfs which could still get such high mmap() addresses. So
in theory that's a potential regression that should have bee addressed
at the same time as commit f6795053da (and before arm64 enabled
52-bit addresses)"
Link: https://lkml.kernel.org/r/ab847b6edb197bffdfe189e70fb4ac76bfe79e0d.1650033747.git.christophe.leroy@csgroup.eu
Fixes: f6795053da ("mm: mmap: Allow for "high" userspace addresses")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org> [5.0.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Rewrite how munlock works to massively reduce the contention
on i_mmap_rwsem (Hugh Dickins):
https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
- Sort out the page refcount mess for ZONE_DEVICE pages (Christoph Hellwig):
https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
- Convert GUP to use folios and make pincount available for order-1
pages. (Matthew Wilcox)
- Convert a few more truncation functions to use folios (Matthew Wilcox)
- Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew Wilcox)
- Convert rmap_walk to use folios (Matthew Wilcox)
- Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
- Add support for creating large folios in readahead (Matthew Wilcox)
-----BEGIN PGP SIGNATURE-----
iQEzBAABCgAdFiEEejHryeLBw/spnjHrDpNsjXcpgj4FAmI4ucgACgkQDpNsjXcp
gj69Wgf6AwqwmO5Tmy+fLScDPqWxmXJofbocae1kyoGHf7Ui91OK4U2j6IpvAr+g
P/vLIK+JAAcTQcrSCjymuEkf4HkGZOR03QQn7maPIEe4eLrZRQDEsmHC1L9gpeJp
s/GMvDWiGE0Tnxu0EOzfVi/yT+qjIl/S8VvqtCoJv1HdzxitZ7+1RDuqImaMC5MM
Qi3uHag78vLmCltLXpIOdpgZhdZexCdL2Y/1npf+b6FVkAJRRNUnA0gRbS7YpoVp
CbxEJcmAl9cpJLuj5i5kIfS9trr+/QcvbUlzRxh4ggC58iqnmF2V09l2MJ7YU3XL
v1O/Elq4lRhXninZFQEm9zjrri7LDQ==
=n9Ad
-----END PGP SIGNATURE-----
Merge tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache
Pull folio updates from Matthew Wilcox:
- Rewrite how munlock works to massively reduce the contention on
i_mmap_rwsem (Hugh Dickins):
https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
- Sort out the page refcount mess for ZONE_DEVICE pages (Christoph
Hellwig):
https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
- Convert GUP to use folios and make pincount available for order-1
pages. (Matthew Wilcox)
- Convert a few more truncation functions to use folios (Matthew
Wilcox)
- Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew
Wilcox)
- Convert rmap_walk to use folios (Matthew Wilcox)
- Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
- Add support for creating large folios in readahead (Matthew Wilcox)
* tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits)
mm/damon: minor cleanup for damon_pa_young
selftests/vm/transhuge-stress: Support file-backed PMD folios
mm/filemap: Support VM_HUGEPAGE for file mappings
mm/readahead: Switch to page_cache_ra_order
mm/readahead: Align file mappings for non-DAX
mm/readahead: Add large folio readahead
mm: Support arbitrary THP sizes
mm: Make large folios depend on THP
mm: Fix READ_ONLY_THP warning
mm/filemap: Allow large folios to be added to the page cache
mm: Turn can_split_huge_page() into can_split_folio()
mm/vmscan: Convert pageout() to take a folio
mm/vmscan: Turn page_check_references() into folio_check_references()
mm/vmscan: Account large folios correctly
mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios
mm/vmscan: Free non-shmem folios without splitting them
mm/rmap: Constify the rmap_walk_control argument
mm/rmap: Convert rmap_walk() to take a folio
mm: Turn page_anon_vma() into folio_anon_vma()
mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read()
...
RLIMIT_MEMLOCK is already reimplemented on top of ucounts now. And
since commit 83c1fd763b ("mm,hugetlb: remove mlock ulimit for
SHM_HUGETLB"), mlock ulimit for SHM_HUGETLB is further removed.
So we should remove this obsolete comment.
Link: https://lkml.kernel.org/r/20220309090623.13036-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
_install_special_mapping() adds the VM_SPECIAL bit VM_DONTEXPAND (and
never attempts to update locked_vm), so it ought to be consistent with
mmap_region() and mlock_fixup(), making sure not to add VM_LOCKED or
VM_LOCKONFAULT. I doubt that this fixes any problem in practice: just
do it for consistency.
Link: https://lkml.kernel.org/r/a85315a9-21d1-6133-c5fc-c89863dfb25b@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__setup() handlers should return 1 if the command line option is handled
and 0 if not (or maybe never return 0; it just pollutes init's
environment). This prevents:
Unknown kernel command line parameters \
"BOOT_IMAGE=/boot/bzImage-517rc5 stack_guard_gap=100", will be \
passed to user space.
Run /sbin/init as init process
with arguments:
/sbin/init
with environment:
HOME=/
TERM=linux
BOOT_IMAGE=/boot/bzImage-517rc5
stack_guard_gap=100
Return 1 to indicate that the boot option has been handled.
Note that there is no warning message if someone enters:
stack_guard_gap=anything_invalid
and 'val' and stack_guard_gap are both set to 0 due to the use of
simple_strtoul(). This could be improved by using kstrtoxxx() and
checking for an error.
It appears that having stack_guard_gap == 0 is valid (if unexpected) since
using "stack_guard_gap=0" on the kernel command line does that.
Link: https://lkml.kernel.org/r/20220222005817.11087-1-rdunlap@infradead.org
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Fixes: 1be7107fbe ("mm: larger stack guard gap, between vmas")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
