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10eaec2f63
14367 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Roman Gushchin
|
10eaec2f63 |
mm: kmem: cleanup (__)memcg_kmem_charge_memcg() arguments
Patch series "mm: memcg: kmem API cleanup", v2. This patchset aims to clean up the kernel memory charging API. It doesn't bring any functional changes, just removes unused arguments, renames some functions and fixes some comments. Currently it's not obvious which functions are most basic (memcg_kmem_(un)charge_memcg()) and which are based on them (memcg_kmem_(un)charge()). The patchset renames these functions and removes unused arguments: TL;DR: was: memcg_kmem_charge_memcg(page, gfp, order, memcg) memcg_kmem_uncharge_memcg(memcg, nr_pages) memcg_kmem_charge(page, gfp, order) memcg_kmem_uncharge(page, order) now: memcg_kmem_charge(memcg, gfp, nr_pages) memcg_kmem_uncharge(memcg, nr_pages) memcg_kmem_charge_page(page, gfp, order) memcg_kmem_uncharge_page(page, order) This patch (of 6): The first argument of memcg_kmem_charge_memcg() and __memcg_kmem_charge_memcg() is the page pointer and it's not used. Let's drop it. Memcg pointer is passed as the last argument. Move it to the first place for consistency with other memcg functions, e.g. __memcg_kmem_uncharge_memcg() or try_charge(). Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Link: http://lkml.kernel.org/r/20200109202659.752357-2-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Roman Gushchin
|
4f103c6363 |
mm: memcg/slab: use mem_cgroup_from_obj()
Sometimes we need to get a memcg pointer from a charged kernel object. The right way to get it depends on whether it's a proper slab object or it's backed by raw pages (e.g. it's a vmalloc alloction). In the first case the kmem_cache->memcg_params.memcg indirection should be used; in other cases it's just page->mem_cgroup. To simplify this task and hide the implementation details let's use the mem_cgroup_from_obj() helper, which takes a pointer to any kernel object and returns a valid memcg pointer or NULL. Passing a kernel address rather than a pointer to a page will allow to use this helper for per-object (rather than per-page) tracked objects in the future. The caller is still responsible to ensure that the returned memcg isn't going away underneath: take the rcu read lock, cgroup mutex etc; depending on the context. mem_cgroup_from_kmem() defined in mm/list_lru.c is now obsolete and can be removed. Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Yafang Shao <laoar.shao@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Link: http://lkml.kernel.org/r/20200117203609.3146239-1-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill Tkhai
|
86daf94efb |
mm/memcontrol.c: allocate shrinker_map on appropriate NUMA node
The shrinker_map may be touched from any cpu (e.g., a bit there may be set by a task running everywhere) but kswapd is always bound to specific node. So allocate shrinker_map from the related NUMA node to respect its NUMA locality. Also, this follows generic way we use for allocation of memcg's per-node data. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Link: http://lkml.kernel.org/r/fff0e636-4c36-ed10-281c-8cdb0687c839@virtuozzo.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Yafang Shao
|
a87425a36f |
mm, memcg: fix build error around the usage of kmem_caches
When I manually set default n to MEMCG_KMEM in init/Kconfig, bellow error
occurs,
mm/slab_common.c: In function 'memcg_slab_start':
mm/slab_common.c:1530:30: error: 'struct mem_cgroup' has no member named
'kmem_caches'
return seq_list_start(&memcg->kmem_caches, *pos);
^
mm/slab_common.c: In function 'memcg_slab_next':
mm/slab_common.c:1537:32: error: 'struct mem_cgroup' has no member named
'kmem_caches'
return seq_list_next(p, &memcg->kmem_caches, pos);
^
mm/slab_common.c: In function 'memcg_slab_show':
mm/slab_common.c:1551:16: error: 'struct mem_cgroup' has no member named
'kmem_caches'
if (p == memcg->kmem_caches.next)
^
CC arch/x86/xen/smp.o
mm/slab_common.c: In function 'memcg_slab_start':
mm/slab_common.c:1531:1: warning: control reaches end of non-void function
[-Wreturn-type]
}
^
mm/slab_common.c: In function 'memcg_slab_next':
mm/slab_common.c:1538:1: warning: control reaches end of non-void function
[-Wreturn-type]
}
^
That's because kmem_caches is defined only when CONFIG_MEMCG_KMEM is set,
while memcg_slab_start() will use it no matter CONFIG_MEMCG_KMEM is defined
or not.
By the way, the reason I mannuly undefined CONFIG_MEMCG_KMEM is to verify
whether my some other code change is still stable when CONFIG_MEMCG_KMEM is
not set. Unfortunately, the existing code has been already unstable since
v4.11.
Fixes:
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Wei Yang
|
cb77445132 |
mm/swap_state.c: use the same way to count page in [add_to|delete_from]_swap_cache
add_to_swap_cache() and delete_from_swap_cache() are counterparts, while currently they use different ways to count pages. It doesn't break anything because we only have two sizes for PageAnon, but this is confusing and not good practice. This patch corrects it by making both functions use hpage_nr_pages(). Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Link: http://lkml.kernel.org/r/20200315012920.2687-1-richard.weiyang@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Yang Shi
|
9a9b6cce63 |
mm: swap: use smp_mb__after_atomic() to order LRU bit set
Memory barrier is needed after setting LRU bit, but smp_mb() is too
strong. Some architectures, i.e. x86, imply memory barrier with atomic
operations, so replacing it with smp_mb__after_atomic() sounds better,
which is nop on strong ordered machines, and full memory barriers on
others. With this change the vm-scalability cases would perform better on
x86, I saw total 6% improvement with this patch and previous inline fix.
The test data (lru-file-readtwice throughput) against v5.6-rc4:
mainline w/ inline fix w/ both (adding this)
150MB 154MB 159MB
Fixes:
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Yang Shi
|
1eb6234e52 |
mm: swap: make page_evictable() inline
When backporting commit |
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Wei Yang
|
2406b76fe8 |
mm/swap_slots.c: assign|reset cache slot by value directly
Currently we use a tmp pointer, pentry, to transfer and reset swap cache slot, which is a little redundant. Swap cache slot stores the entry value directly, assign and reset it by value would be straight forward. Also this patch merges the else and if, since this is the only case we refill and repeat swap cache. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/20200311055352.50574-1-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Qian Cai
|
218209487c |
mm/swapfile: fix data races in try_to_unuse()
si->inuse_pages could be accessed concurrently as noticed by KCSAN, write to 0xffff98b00ebd04dc of 4 bytes by task 82262 on cpu 92: swap_range_free+0xbe/0x230 swap_range_free at mm/swapfile.c:719 swapcache_free_entries+0x1be/0x250 free_swap_slot+0x1c8/0x220 __swap_entry_free.constprop.19+0xa3/0xb0 free_swap_and_cache+0x53/0xa0 unmap_page_range+0x7e0/0x1ce0 unmap_single_vma+0xcd/0x170 unmap_vmas+0x18b/0x220 exit_mmap+0xee/0x220 mmput+0xe7/0x240 do_exit+0x598/0xfd0 do_group_exit+0x8b/0x180 get_signal+0x293/0x13d0 do_signal+0x37/0x5d0 prepare_exit_to_usermode+0x1b7/0x2c0 ret_from_intr+0x32/0x42 read to 0xffff98b00ebd04dc of 4 bytes by task 82499 on cpu 46: try_to_unuse+0x86b/0xc80 try_to_unuse at mm/swapfile.c:2185 __x64_sys_swapoff+0x372/0xd40 do_syscall_64+0x91/0xb05 entry_SYSCALL_64_after_hwframe+0x49/0xbe The plain reads in try_to_unuse() are outside si->lock critical section which result in data races that could be dangerous to be used in a loop. Fix them by adding READ_ONCE(). Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Hugh Dickins <hughd@google.com> Link: http://lkml.kernel.org/r/1582578903-29294-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Wei Yang
|
bde07cfc65 |
mm/swap.c: not necessary to export __pagevec_lru_add()
__pagevec_lru_add() is only used in mm directory now. Remove the export symbol. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200126011436.22979-1-richardw.yang@linux.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Chen Wandun
|
3eeba1356d |
mm/swapfile.c: fix comments for swapcache_prepare
The -EEXIST returned by __swap_duplicate means there is a swap cache instead -EBUSY Signed-off-by: Chen Wandun <chenwandun@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200212145754.27123-1-chenwandun@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Pingfan Liu
|
df3a0a21b6 |
mm/gup: fix omission of check on FOLL_LONGTERM in gup fast path
FOLL_LONGTERM is a special case of FOLL_PIN. It suggests a pin which is going to be given to hardware and can't move. It would truncate CMA permanently and should be excluded. In gup slow path, where __gup_longterm_locked->check_and_migrate_cma_pages() handles FOLL_LONGTERM, but in fast path, there lacks such a check, which means a possible leak of CMA page to longterm pinned. Place a check in try_grab_compound_head() in the fast path to fix the leak, and if FOLL_LONGTERM happens on CMA, it will fall back to slow path to migrate the page. Some note about the check: Huge page's subpages have the same migrate type due to either allocation from a free_list[] or alloc_contig_range() with param MIGRATE_MOVABLE. So it is enough to check on a single subpage by is_migrate_cma_page(subpage) Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Link: http://lkml.kernel.org/r/1584876733-17405-3-git-send-email-kernelfans@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Pingfan Liu
|
4628b063d2 |
mm/gup: rename nr as nr_pinned in get_user_pages_fast()
To better reflect the held state of pages and make code self-explaining, rename nr as nr_pinned. Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Link: http://lkml.kernel.org/r/1584876733-17405-2-git-send-email-kernelfans@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Claudio Imbrenda
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f28d43636d |
mm/gup/writeback: add callbacks for inaccessible pages
With the introduction of protected KVM guests on s390 there is now a concept of inaccessible pages. These pages need to be made accessible before the host can access them. While cpu accesses will trigger a fault that can be resolved, I/O accesses will just fail. We need to add a callback into architecture code for places that will do I/O, namely when writeback is started or when a page reference is taken. This is not only to enable paging, file backing etc, it is also necessary to protect the host against a malicious user space. For example a bad QEMU could simply start direct I/O on such protected memory. We do not want userspace to be able to trigger I/O errors and thus the logic is "whenever somebody accesses that page (gup) or does I/O, make sure that this page can be accessed". When the guest tries to access that page we will wait in the page fault handler for writeback to have finished and for the page_ref to be the expected value. On s390x the function is not supposed to fail, so it is ok to use a WARN_ON on failure. If we ever need some more finegrained handling we can tackle this when we know the details. Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Will Deacon <will@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200306132537.783769-3-imbrenda@linux.ibm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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John Hubbard
|
dc8fb2f282 |
mm: dump_page(): additional diagnostics for huge pinned pages
As part of pin_user_pages() and related API calls, pages are "dma-pinned". For the case of compound pages of order > 1, the per-page accounting of dma pins is accomplished via the 3rd struct page in the compound page. In order to support debugging of any pin_user_pages()- related problems, enhance dump_page() so as to report the pin count in that case. Documentation/core-api/pin_user_pages.rst is also updated accordingly. Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200211001536.1027652-13-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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6197ab984b |
mm: improve dump_page() for compound pages
There was no protection against a corrupted struct page having an implausible compound_head(). Sanity check that a compound page has a head within reach of the maximum allocatable page (this will need to be adjusted if one of the plans to allocate 1GB pages comes to fruition). In addition, - Print the mapping pointer using %p insted of %px. The actual value of the pointer can be read out of the raw page dump and using %p gives a chance to correlate it with an earlier printk of the mapping pointer - Print the mapping pointer from the head page, not the tail page (the tail ->mapping pointer may be in use for other purposes, eg part of a list_head) - Print the order of the page for compound pages - Dump the raw head page as well as the raw page - Print the refcount from the head page, not the tail page Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Co-developed-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200211001536.1027652-12-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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John Hubbard
|
41c45d37b9 |
mm/gup_benchmark: support pin_user_pages() and related calls
Up until now, gup_benchmark supported testing of the following kernel
functions:
* get_user_pages(): via the '-U' command line option
* get_user_pages_longterm(): via the '-L' command line option
* get_user_pages_fast(): as the default (no options required)
Add test coverage for the new corresponding pin_*() functions:
* pin_user_pages_fast(): via the '-a' command line option
* pin_user_pages(): via the '-b' command line option
Also, add an option for clarity: '-u' for what is now (still) the default
choice: get_user_pages_fast().
Also, for the commands that set FOLL_PIN, verify that the pages really are
dma-pinned, via the new is_dma_pinned() routine. Those commands are:
PIN_FAST_BENCHMARK : calls pin_user_pages_fast()
PIN_BENCHMARK : calls pin_user_pages()
In between the calls to pin_*() and unpin_user_pages(), check each page:
if page_maybe_dma_pinned() returns false, then WARN and return.
Do this outside of the benchmark timestamps, so that it doesn't affect
reported times.
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200211001536.1027652-10-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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John Hubbard
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1970dc6f52 |
mm/gup: /proc/vmstat: pin_user_pages (FOLL_PIN) reporting
Now that pages are "DMA-pinned" via pin_user_page*(), and unpinned via
unpin_user_pages*(), we need some visibility into whether all of this is
working correctly.
Add two new fields to /proc/vmstat:
nr_foll_pin_acquired
nr_foll_pin_released
These are documented in Documentation/core-api/pin_user_pages.rst. They
represent the number of pages (since boot time) that have been pinned
("nr_foll_pin_acquired") and unpinned ("nr_foll_pin_released"), via
pin_user_pages*() and unpin_user_pages*().
In the absence of long-running DMA or RDMA operations that hold pages
pinned, the above two fields will normally be equal to each other.
Also: update Documentation/core-api/pin_user_pages.rst, to remove an
earlier (now confirmed untrue) claim about a performance problem with
/proc/vmstat.
Also: update Documentation/core-api/pin_user_pages.rst to rename the new
/proc/vmstat entries, to the names listed here.
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200211001536.1027652-9-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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John Hubbard
|
47e29d32af |
mm/gup: page->hpage_pinned_refcount: exact pin counts for huge pages
For huge pages (and in fact, any compound page), the GUP_PIN_COUNTING_BIAS scheme tends to overflow too easily, each tail page increments the head page->_refcount by GUP_PIN_COUNTING_BIAS (1024). That limits the number of huge pages that can be pinned. This patch removes that limitation, by using an exact form of pin counting for compound pages of order > 1. The "order > 1" is required because this approach uses the 3rd struct page in the compound page, and order 1 compound pages only have two pages, so that won't work there. A new struct page field, hpage_pinned_refcount, has been added, replacing a padding field in the union (so no new space is used). This enhancement also has a useful side effect: huge pages and compound pages (of order > 1) do not suffer from the "potential false positives" problem that is discussed in the page_dma_pinned() comment block. That is because these compound pages have extra space for tracking things, so they get exact pin counts instead of overloading page->_refcount. Documentation/core-api/pin_user_pages.rst is updated accordingly. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200211001536.1027652-8-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
John Hubbard
|
3faa52c03f |
mm/gup: track FOLL_PIN pages
Add tracking of pages that were pinned via FOLL_PIN. This tracking is
implemented via overloading of page->_refcount: pins are added by adding
GUP_PIN_COUNTING_BIAS (1024) to the refcount. This provides a fuzzy
indication of pinning, and it can have false positives (and that's OK).
Please see the pre-existing Documentation/core-api/pin_user_pages.rst for
details.
As mentioned in pin_user_pages.rst, callers who effectively set FOLL_PIN
(typically via pin_user_pages*()) are required to ultimately free such
pages via unpin_user_page().
Please also note the limitation, discussed in pin_user_pages.rst under the
"TODO: for 1GB and larger huge pages" section. (That limitation will be
removed in a following patch.)
The effect of a FOLL_PIN flag is similar to that of FOLL_GET, and may be
thought of as "FOLL_GET for DIO and/or RDMA use".
Pages that have been pinned via FOLL_PIN are identifiable via a new
function call:
bool page_maybe_dma_pinned(struct page *page);
What to do in response to encountering such a page, is left to later
patchsets. There is discussion about this in [1], [2], [3], and [4].
This also changes a BUG_ON(), to a WARN_ON(), in follow_page_mask().
[1] Some slow progress on get_user_pages() (Apr 2, 2019):
https://lwn.net/Articles/784574/
[2] DMA and get_user_pages() (LPC: Dec 12, 2018):
https://lwn.net/Articles/774411/
[3] The trouble with get_user_pages() (Apr 30, 2018):
https://lwn.net/Articles/753027/
[4] LWN kernel index: get_user_pages():
https://lwn.net/Kernel/Index/#Memory_management-get_user_pages
[jhubbard@nvidia.com: add kerneldoc]
Link: http://lkml.kernel.org/r/20200307021157.235726-1-jhubbard@nvidia.com
[imbrenda@linux.ibm.com: if pin fails, we need to unpin, a simple put_page will not be enough]
Link: http://lkml.kernel.org/r/20200306132537.783769-2-imbrenda@linux.ibm.com
[akpm@linux-foundation.org: fix put_compound_head defined but not used]
Suggested-by: Jan Kara <jack@suse.cz>
Suggested-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200211001536.1027652-7-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
|
John Hubbard
|
94202f126f |
mm/gup: require FOLL_GET for get_user_pages_fast()
Internal to mm/gup.c, require that get_user_pages_fast() and __get_user_pages_fast() identify themselves, by setting FOLL_GET. This is required in order to be able to make decisions based on "FOLL_PIN, or FOLL_GET, or both or neither are set", in upcoming patches. Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200211001536.1027652-6-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
John Hubbard
|
3b78d8347d |
mm/gup: pass gup flags to two more routines
In preparation for an upcoming patch, send gup flags args to two more routines: put_compound_head(), and undo_dev_pagemap(). Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200211001536.1027652-5-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
John Hubbard
|
86dfbed49f |
mm/gup: pass a flags arg to __gup_device_* functions
A subsequent patch requires access to gup flags, so pass the flags argument through to the __gup_device_* functions. Also placate checkpatch.pl by shortening a nearby line. Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200211001536.1027652-3-jhubbard@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
John Hubbard
|
22bf29b67d |
mm/gup: split get_user_pages_remote() into two routines
Patch series "mm/gup: track FOLL_PIN pages", v6.
This activates tracking of FOLL_PIN pages. This is in support of fixing
the get_user_pages()+DMA problem described in [1]-[4].
FOLL_PIN support is now in the main linux tree. However, the patch to use
FOLL_PIN to track pages was *not* submitted, because Leon saw an RDMA test
suite failure that involved (I think) page refcount overflows when huge
pages were used.
This patch definitively solves that kind of overflow problem, by adding an
exact pincount, for compound pages (of order > 1), in the 3rd struct page
of a compound page. If available, that form of pincounting is used,
instead of the GUP_PIN_COUNTING_BIAS approach. Thanks again to Jan Kara
for that idea.
Other interesting changes:
* dump_page(): added one, or two new things to report for compound
pages: head refcount (for all compound pages), and map_pincount (for
compound pages of order > 1).
* Documentation/core-api/pin_user_pages.rst: removed the "TODO" for the
huge page refcount upper limit problems, and added notes about how it
works now. Also added a note about the dump_page() enhancements.
* Added some comments in gup.c and mm.h, to explain that there are two
ways to count pinned pages: exact (for compound pages of order > 1) and
fuzzy (GUP_PIN_COUNTING_BIAS: for all other pages).
============================================================
General notes about the tracking patch:
This is a prerequisite to solving the problem of proper interactions
between file-backed pages, and [R]DMA activities, as discussed in [1],
[2], [3], [4] and in a remarkable number of email threads since about
2017. :)
In contrast to earlier approaches, the page tracking can be incrementally
applied to the kernel call sites that, until now, have been simply calling
get_user_pages() ("gup"). In other words, opt-in by changing from this:
get_user_pages() (sets FOLL_GET)
put_page()
to this:
pin_user_pages() (sets FOLL_PIN)
unpin_user_page()
============================================================
Future steps:
* Convert more subsystems from get_user_pages() to pin_user_pages().
The first probably needs to be bio/biovecs, because any filesystem
testing is too difficult without those in place.
* Change VFS and filesystems to respond appropriately when encountering
dma-pinned pages.
* Work with Ira and others to connect this all up with file system
leases.
[1] Some slow progress on get_user_pages() (Apr 2, 2019):
https://lwn.net/Articles/784574/
[2] DMA and get_user_pages() (LPC: Dec 12, 2018):
https://lwn.net/Articles/774411/
[3] The trouble with get_user_pages() (Apr 30, 2018):
https://lwn.net/Articles/753027/
[4] LWN kernel index: get_user_pages()
https://lwn.net/Kernel/Index/#Memory_management-get_user_pages
This patch (of 12):
An upcoming patch requires reusing the implementation of
get_user_pages_remote(). Split up get_user_pages_remote() into an outer
routine that checks flags, and an implementation routine that will be
reused. This makes subsequent changes much easier to understand.
There should be no change in behavior due to this patch.
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200211001536.1027652-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
|
Matthew Wilcox (Oracle)
|
2294b32e06 |
mm/filemap.c: rewrite pagecache_get_page documentation
- These were never called PCG flags; they've been called FGP flags since their introduction in 2014. - The FGP_FOR_MMAP flag was misleadingly documented as if it was an alternative to FGP_CREAT instead of an option to it. - Rename the 'offset' parameter to 'index'. - Capitalisation, formatting, rewording. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Link: http://lkml.kernel.org/r/20200318140253.6141-9-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
83daf83788 |
mm/filemap.c: unexport find_get_entry
No in-tree users (proc, madvise, memcg, mincore) can be built as a module. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Link: http://lkml.kernel.org/r/20200318140253.6141-8-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
184b4fef58 |
mm/page-writeback.c: use VM_BUG_ON_PAGE in clear_page_dirty_for_io
Dumping the page information in this circumstance helps for debugging. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Link: http://lkml.kernel.org/r/20200318140253.6141-7-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
e520e932dc |
mm/filemap.c: use vm_fault error code directly
Use VM_FAULT_OOM instead of indirecting through vmf_error(-ENOMEM). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Link: http://lkml.kernel.org/r/20200318140253.6141-2-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Souptick Joarder
|
0f8e2db4ea |
mm/filemap.c: remove unused argument from shrink_readahead_size_eio()
The first argument of shrink_readahead_size_eio() is not used. Hence remove it from the function definition and from all the callers. Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1583868093-24342-1-git-send-email-jrdr.linux@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Xianting Tian
|
faffdfa04f |
mm/filemap.c: clear page error before actual read
Mount failure issue happens under the scenario: Application forked dozens
of threads to mount the same number of cramfs images separately in docker,
but several mounts failed with high probability. Mount failed due to the
checking result of the page(read from the superblock of loop dev) is not
uptodate after wait_on_page_locked(page) returned in function cramfs_read:
wait_on_page_locked(page);
if (!PageUptodate(page)) {
...
}
The reason of the checking result of the page not uptodate: systemd-udevd
read the loopX dev before mount, because the status of loopX is Lo_unbound
at this time, so loop_make_request directly trigger the calling of io_end
handler end_buffer_async_read, which called SetPageError(page). So It
caused the page can't be set to uptodate in function
end_buffer_async_read:
if(page_uptodate && !PageError(page)) {
SetPageUptodate(page);
}
Then mount operation is performed, it used the same page which is just
accessed by systemd-udevd above, Because this page is not uptodate, it
will launch a actual read via submit_bh, then wait on this page by calling
wait_on_page_locked(page). When the I/O of the page done, io_end handler
end_buffer_async_read is called, because no one cleared the page
error(during the whole read path of mount), which is caused by
systemd-udevd reading, so this page is still in "PageError" status, which
can't be set to uptodate in function end_buffer_async_read, then caused
mount failure.
But sometimes mount succeed even through systemd-udeved read loopX dev
just before, The reason is systemd-udevd launched other loopX read just
between step 3.1 and 3.2, the steps as below:
1, loopX dev default status is Lo_unbound;
2, systemd-udved read loopX dev (page is set to PageError);
3, mount operation
1) set loopX status to Lo_bound;
==>systemd-udevd read loopX dev<==
2) read loopX dev(page has no error)
3) mount succeed
As the loopX dev status is set to Lo_bound after step 3.1, so the other
loopX dev read by systemd-udevd will go through the whole I/O stack, part
of the call trace as below:
SYS_read
vfs_read
do_sync_read
blkdev_aio_read
generic_file_aio_read
do_generic_file_read:
ClearPageError(page);
mapping->a_ops->readpage(filp, page);
here, mapping->a_ops->readpage() is blkdev_readpage. In latest kernel,
some function name changed, the call trace as below:
blkdev_read_iter
generic_file_read_iter
generic_file_buffered_read:
/*
* A previous I/O error may have been due to temporary
* failures, eg. mutipath errors.
* Pg_error will be set again if readpage fails.
*/
ClearPageError(page);
/* Start the actual read. The read will unlock the page*/
error=mapping->a_ops->readpage(flip, page);
We can see ClearPageError(page) is called before the actual read,
then the read in step 3.2 succeed.
This patch is to add the calling of ClearPageError just before the actual
read of read path of cramfs mount. Without the patch, the call trace as
below when performing cramfs mount:
do_mount
cramfs_read
cramfs_blkdev_read
read_cache_page
do_read_cache_page:
filler(data, page);
or
mapping->a_ops->readpage(data, page);
With the patch, the call trace as below when performing mount:
do_mount
cramfs_read
cramfs_blkdev_read
read_cache_page:
do_read_cache_page:
ClearPageError(page); <== new add
filler(data, page);
or
mapping->a_ops->readpage(data, page);
With the patch, mount operation trigger the calling of
ClearPageError(page) before the actual read, the page has no error if no
additional page error happen when I/O done.
Signed-off-by: Xianting Tian <xianting_tian@126.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: <yubin@h3c.com>
Link: http://lkml.kernel.org/r/1583318844-22971-1-git-send-email-xianting_tian@126.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
|
Mauricio Faria de Oliveira
|
cc7b8f6245 |
mm/page-writeback.c: write_cache_pages(): deduplicate identical checks
There used to be a 'retry' label in between the two (identical) checks when first introduced in commit |
||
|
Jan Kara
|
5c72feee3e |
mm/filemap.c: don't bother dropping mmap_sem for zero size readahead
When handling a page fault, we drop mmap_sem to start async readahead so
that we don't block on IO submission with mmap_sem held. However there's
no point to drop mmap_sem in case readahead is disabled. Handle that case
to avoid pointless dropping of mmap_sem and retrying the fault. This was
actually reported to block mlockall(MCL_CURRENT) indefinitely.
Fixes:
|
||
|
Qian Cai
|
5f2d5026be |
mm/Makefile: disable KCSAN for kmemleak
Kmemleak could scan task stacks while plain writes happens to those stack variables which could results in data races. For example, in sys_rt_sigaction and do_sigaction(), it could have plain writes in a 32-byte size. Since the kmemleak does not care about the actual values of a non-pointer and all do_sigaction() call sites only copy to stack variables, just disable KCSAN for kmemleak to avoid annotating anything outside Kmemleak just because Kmemleak scans everything. Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Marco Elver <elver@google.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: http://lkml.kernel.org/r/1583263716-25150-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Nathan Chancellor
|
b0d14fc43d |
mm/kmemleak.c: use address-of operator on section symbols
Clang warns:
mm/kmemleak.c:1955:28: warning: array comparison always evaluates to a constant [-Wtautological-compare]
if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
^
mm/kmemleak.c:1955:60: warning: array comparison always evaluates to a constant [-Wtautological-compare]
if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
These are not true arrays, they are linker defined symbols, which are just
addresses. Using the address of operator silences the warning and does
not change the resulting assembly with either clang/ld.lld or gcc/ld
(tested with diff + objdump -Dr).
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/895
Link: http://lkml.kernel.org/r/20200220051551.44000-1-natechancellor@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
|
Vlastimil Babka
|
667c790169 |
revert "topology: add support for node_to_mem_node() to determine the fallback node"
This reverts commit |
||
|
Kees Cook
|
3202fa62fb |
slub: relocate freelist pointer to middle of object
In a recent discussion[1] with Vitaly Nikolenko and Silvio Cesare, it became clear that moving the freelist pointer away from the edge of allocations would likely improve the overall defensive posture of the inline freelist pointer. My benchmarks show no meaningful change to performance (they seem to show it being faster), so this looks like a reasonable change to make. Instead of having the freelist pointer at the very beginning of an allocation (offset 0) or at the very end of an allocation (effectively offset -sizeof(void *) from the next allocation), move it away from the edges of the allocation and into the middle. This provides some protection against small-sized neighboring overflows (or underflows), for which the freelist pointer is commonly the target. (Large or well controlled overwrites are much more likely to attack live object contents, instead of attempting freelist corruption.) The vaunted kernel build benchmark, across 5 runs. Before: Mean: 250.05 Std Dev: 1.85 and after, which appears mysteriously faster: Mean: 247.13 Std Dev: 0.76 Attempts at running "sysbench --test=memory" show the change to be well in the noise (sysbench seems to be pretty unstable here -- it's not really measuring allocation). Hackbench is more allocation-heavy, and while the std dev is above the difference, it looks like may manifest as an improvement as well: 20 runs of "hackbench -g 20 -l 1000", before: Mean: 36.322 Std Dev: 0.577 and after: Mean: 36.056 Std Dev: 0.598 [1] https://twitter.com/vnik5287/status/1235113523098685440 Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Christoph Lameter <cl@linux.com> Cc: Vitaly Nikolenko <vnik@duasynt.com> Cc: Silvio Cesare <silvio.cesare@gmail.com> Cc: Christoph Lameter <cl@linux.com>Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Link: http://lkml.kernel.org/r/202003051624.AAAC9AECC@keescook Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Kees Cook
|
1ad53d9fa3 |
slub: improve bit diffusion for freelist ptr obfuscation
Under CONFIG_SLAB_FREELIST_HARDENED=y, the obfuscation was relatively weak
in that the ptr and ptr address were usually so close that the first XOR
would result in an almost entirely 0-byte value[1], leaving most of the
"secret" number ultimately being stored after the third XOR. A single
blind memory content exposure of the freelist was generally sufficient to
learn the secret.
Add a swab() call to mix bits a little more. This is a cheap way (1
cycle) to make attacks need more than a single exposure to learn the
secret (or to know _where_ the exposure is in memory).
kmalloc-32 freelist walk, before:
ptr ptr_addr stored value secret
ffff90c22e019020@ffff90c22e019000 is 86528eb656b3b5bd (86528eb656b3b59d)
ffff90c22e019040@ffff90c22e019020 is 86528eb656b3b5fd (86528eb656b3b59d)
ffff90c22e019060@ffff90c22e019040 is 86528eb656b3b5bd (86528eb656b3b59d)
ffff90c22e019080@ffff90c22e019060 is 86528eb656b3b57d (86528eb656b3b59d)
ffff90c22e0190a0@ffff90c22e019080 is 86528eb656b3b5bd (86528eb656b3b59d)
...
after:
ptr ptr_addr stored value secret
ffff9eed6e019020@ffff9eed6e019000 is 793d1135d52cda42 (86528eb656b3b59d)
ffff9eed6e019040@ffff9eed6e019020 is 593d1135d52cda22 (86528eb656b3b59d)
ffff9eed6e019060@ffff9eed6e019040 is 393d1135d52cda02 (86528eb656b3b59d)
ffff9eed6e019080@ffff9eed6e019060 is 193d1135d52cdae2 (86528eb656b3b59d)
ffff9eed6e0190a0@ffff9eed6e019080 is f93d1135d52cdac2 (86528eb656b3b59d)
[1] https://blog.infosectcbr.com.au/2020/03/weaknesses-in-linux-kernel-heap.html
Fixes:
|
||
|
chenqiwu
|
bbd4e305e3 |
mm/slub.c: replace kmem_cache->cpu_partial with wrapped APIs
There are slub_cpu_partial() and slub_set_cpu_partial() APIs to wrap kmem_cache->cpu_partial. This patch will use the two APIs to replace kmem_cache->cpu_partial in slub code. Signed-off-by: chenqiwu <chenqiwu@xiaomi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Link: http://lkml.kernel.org/r/1582079562-17980-1-git-send-email-qiwuchen55@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
chenqiwu
|
4c7ba22e4c |
mm/slub.c: replace cpu_slab->partial with wrapped APIs
There are slub_percpu_partial() and slub_set_percpu_partial() APIs to wrap kmem_cache->cpu_partial. This patch will use the two to replace cpu_slab->partial in slub code. Signed-off-by: chenqiwu <chenqiwu@xiaomi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Link: http://lkml.kernel.org/r/1581951895-3038-1-git-send-email-qiwuchen55@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Linus Torvalds
|
3cd86a58f7 |
arm64 updates for 5.7:
- In-kernel Pointer Authentication support (previously only offered to
user space).
- ARM Activity Monitors (AMU) extension support allowing better CPU
utilisation numbers for the scheduler (frequency invariance).
- Memory hot-remove support for arm64.
- Lots of asm annotations (SYM_*) in preparation for the in-kernel
Branch Target Identification (BTI) support.
- arm64 perf updates: ARMv8.5-PMU 64-bit counters, refactoring the PMU
init callbacks, support for new DT compatibles.
- IPv6 header checksum optimisation.
- Fixes: SDEI (software delegated exception interface) double-lock on
hibernate with shared events.
- Minor clean-ups and refactoring: cpu_ops accessor, cpu_do_switch_mm()
converted to C, cpufeature finalisation helper.
- sys_mremap() comment explaining the asymmetric address untagging
behaviour.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
"The bulk is in-kernel pointer authentication, activity monitors and
lots of asm symbol annotations. I also queued the sys_mremap() patch
commenting the asymmetry in the address untagging.
Summary:
- In-kernel Pointer Authentication support (previously only offered
to user space).
- ARM Activity Monitors (AMU) extension support allowing better CPU
utilisation numbers for the scheduler (frequency invariance).
- Memory hot-remove support for arm64.
- Lots of asm annotations (SYM_*) in preparation for the in-kernel
Branch Target Identification (BTI) support.
- arm64 perf updates: ARMv8.5-PMU 64-bit counters, refactoring the
PMU init callbacks, support for new DT compatibles.
- IPv6 header checksum optimisation.
- Fixes: SDEI (software delegated exception interface) double-lock on
hibernate with shared events.
- Minor clean-ups and refactoring: cpu_ops accessor,
cpu_do_switch_mm() converted to C, cpufeature finalisation helper.
- sys_mremap() comment explaining the asymmetric address untagging
behaviour"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (81 commits)
mm/mremap: Add comment explaining the untagging behaviour of mremap()
arm64: head: Convert install_el2_stub to SYM_INNER_LABEL
arm64: Introduce get_cpu_ops() helper function
arm64: Rename cpu_read_ops() to init_cpu_ops()
arm64: Declare ACPI parking protocol CPU operation if needed
arm64: move kimage_vaddr to .rodata
arm64: use mov_q instead of literal ldr
arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH
lkdtm: arm64: test kernel pointer authentication
arm64: compile the kernel with ptrauth return address signing
kconfig: Add support for 'as-option'
arm64: suspend: restore the kernel ptrauth keys
arm64: __show_regs: strip PAC from lr in printk
arm64: unwind: strip PAC from kernel addresses
arm64: mask PAC bits of __builtin_return_address
arm64: initialize ptrauth keys for kernel booting task
arm64: initialize and switch ptrauth kernel keys
arm64: enable ptrauth earlier
arm64: cpufeature: handle conflicts based on capability
arm64: cpufeature: Move cpu capability helpers inside C file
...
|
||
|
Aneesh Kumar K.V
|
b943f045a9 |
mm/sparse: fix kernel crash with pfn_section_valid check
Fix the crash like this:
BUG: Kernel NULL pointer dereference on read at 0x00000000
Faulting instruction address: 0xc000000000c3447c
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
CPU: 11 PID: 7519 Comm: lt-ndctl Not tainted 5.6.0-rc7-autotest #1
...
NIP [c000000000c3447c] vmemmap_populated+0x98/0xc0
LR [c000000000088354] vmemmap_free+0x144/0x320
Call Trace:
section_deactivate+0x220/0x240
__remove_pages+0x118/0x170
arch_remove_memory+0x3c/0x150
memunmap_pages+0x1cc/0x2f0
devm_action_release+0x30/0x50
release_nodes+0x2f8/0x3e0
device_release_driver_internal+0x168/0x270
unbind_store+0x130/0x170
drv_attr_store+0x44/0x60
sysfs_kf_write+0x68/0x80
kernfs_fop_write+0x100/0x290
__vfs_write+0x3c/0x70
vfs_write+0xcc/0x240
ksys_write+0x7c/0x140
system_call+0x5c/0x68
The crash is due to NULL dereference at
test_bit(idx, ms->usage->subsection_map);
due to ms->usage = NULL in pfn_section_valid()
With commit
|
||
|
Roman Gushchin
|
8380ce4790 |
mm: fork: fix kernel_stack memcg stats for various stack implementations
Depending on CONFIG_VMAP_STACK and the THREAD_SIZE / PAGE_SIZE ratio the
space for task stacks can be allocated using __vmalloc_node_range(),
alloc_pages_node() and kmem_cache_alloc_node().
In the first and the second cases page->mem_cgroup pointer is set, but
in the third it's not: memcg membership of a slab page should be
determined using the memcg_from_slab_page() function, which looks at
page->slab_cache->memcg_params.memcg . In this case, using
mod_memcg_page_state() (as in account_kernel_stack()) is incorrect:
page->mem_cgroup pointer is NULL even for pages charged to a non-root
memory cgroup.
It can lead to kernel_stack per-memcg counters permanently showing 0 on
some architectures (depending on the configuration).
In order to fix it, let's introduce a mod_memcg_obj_state() helper,
which takes a pointer to a kernel object as a first argument, uses
mem_cgroup_from_obj() to get a RCU-protected memcg pointer and calls
mod_memcg_state(). It allows to handle all possible configurations
(CONFIG_VMAP_STACK and various THREAD_SIZE/PAGE_SIZE values) without
spilling any memcg/kmem specifics into fork.c .
Note: This is a special version of the patch created for stable
backports. It contains code from the following two patches:
- mm: memcg/slab: introduce mem_cgroup_from_obj()
- mm: fork: fix kernel_stack memcg stats for various stack implementations
[guro@fb.com: introduce mem_cgroup_from_obj()]
Link: http://lkml.kernel.org/r/20200324004221.GA36662@carbon.dhcp.thefacebook.com
Fixes:
|
||
|
Mina Almasry
|
726b7bbeaf |
hugetlb_cgroup: fix illegal access to memory
This appears to be a mistake in commit |
||
|
Naohiro Aota
|
d795a90e2b |
mm/swapfile.c: move inode_lock out of claim_swapfile
claim_swapfile() currently keeps the inode locked when it is successful,
or the file is already swapfile (with -EBUSY). And, on the other error
cases, it does not lock the inode.
This inconsistency of the lock state and return value is quite confusing
and actually causing a bad unlock balance as below in the "bad_swap"
section of __do_sys_swapon().
This commit fixes this issue by moving the inode_lock() and IS_SWAPFILE
check out of claim_swapfile(). The inode is unlocked in
"bad_swap_unlock_inode" section, so that the inode is ensured to be
unlocked at "bad_swap". Thus, error handling codes after the locking now
jumps to "bad_swap_unlock_inode" instead of "bad_swap".
=====================================
WARNING: bad unlock balance detected!
5.5.0-rc7+ #176 Not tainted
-------------------------------------
swapon/4294 is trying to release lock (&sb->s_type->i_mutex_key) at: __do_sys_swapon+0x94b/0x3550
but there are no more locks to release!
other info that might help us debug this:
no locks held by swapon/4294.
stack backtrace:
CPU: 5 PID: 4294 Comm: swapon Not tainted 5.5.0-rc7-BTRFS-ZNS+ #176
Hardware name: ASUS All Series/H87-PRO, BIOS 2102 07/29/2014
Call Trace:
dump_stack+0xa1/0xea
print_unlock_imbalance_bug.cold+0x114/0x123
lock_release+0x562/0xed0
up_write+0x2d/0x490
__do_sys_swapon+0x94b/0x3550
__x64_sys_swapon+0x54/0x80
do_syscall_64+0xa4/0x4b0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f15da0a0dc7
Fixes:
|
||
|
Will Deacon
|
b2a84de2a2 |
mm/mremap: Add comment explaining the untagging behaviour of mremap()
Commit
|
||
|
Joerg Roedel
|
763802b53a |
x86/mm: split vmalloc_sync_all()
Commit |
||
|
Vlastimil Babka
|
0715e6c516 |
mm, slub: prevent kmalloc_node crashes and memory leaks
Sachin reports [1] a crash in SLUB __slab_alloc(): BUG: Kernel NULL pointer dereference on read at 0x000073b0 Faulting instruction address: 0xc0000000003d55f4 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 19 PID: 1 Comm: systemd Not tainted 5.6.0-rc2-next-20200218-autotest #1 NIP: c0000000003d55f4 LR: c0000000003d5b94 CTR: 0000000000000000 REGS: c0000008b37836d0 TRAP: 0300 Not tainted (5.6.0-rc2-next-20200218-autotest) MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 24004844 XER: 00000000 CFAR: c00000000000dec4 DAR: 00000000000073b0 DSISR: 40000000 IRQMASK: 1 GPR00: c0000000003d5b94 c0000008b3783960 c00000000155d400 c0000008b301f500 GPR04: 0000000000000dc0 0000000000000002 c0000000003443d8 c0000008bb398620 GPR08: 00000008ba2f0000 0000000000000001 0000000000000000 0000000000000000 GPR12: 0000000024004844 c00000001ec52a00 0000000000000000 0000000000000000 GPR16: c0000008a1b20048 c000000001595898 c000000001750c18 0000000000000002 GPR20: c000000001750c28 c000000001624470 0000000fffffffe0 5deadbeef0000122 GPR24: 0000000000000001 0000000000000dc0 0000000000000002 c0000000003443d8 GPR28: c0000008b301f500 c0000008bb398620 0000000000000000 c00c000002287180 NIP ___slab_alloc+0x1f4/0x760 LR __slab_alloc+0x34/0x60 Call Trace: ___slab_alloc+0x334/0x760 (unreliable) __slab_alloc+0x34/0x60 __kmalloc_node+0x110/0x490 kvmalloc_node+0x58/0x110 mem_cgroup_css_online+0x108/0x270 online_css+0x48/0xd0 cgroup_apply_control_enable+0x2ec/0x4d0 cgroup_mkdir+0x228/0x5f0 kernfs_iop_mkdir+0x90/0xf0 vfs_mkdir+0x110/0x230 do_mkdirat+0xb0/0x1a0 system_call+0x5c/0x68 This is a PowerPC platform with following NUMA topology: available: 2 nodes (0-1) node 0 cpus: node 0 size: 0 MB node 0 free: 0 MB node 1 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 node 1 size: 35247 MB node 1 free: 30907 MB node distances: node 0 1 0: 10 40 1: 40 10 possible numa nodes: 0-31 This only happens with a mmotm patch "mm/memcontrol.c: allocate shrinker_map on appropriate NUMA node" [2] which effectively calls kmalloc_node for each possible node. SLUB however only allocates kmem_cache_node on online N_NORMAL_MEMORY nodes, and relies on node_to_mem_node to return such valid node for other nodes since commit |
||
|
Qian Cai
|
63886bad90 |
mm/mmu_notifier: silence PROVE_RCU_LIST warnings
It is safe to traverse mm->notifier_subscriptions->list either under SRCU read lock or mm->notifier_subscriptions->lock using hlist_for_each_entry_rcu(). Silence the PROVE_RCU_LIST false positives, for example, WARNING: suspicious RCU usage ----------------------------- mm/mmu_notifier.c:484 RCU-list traversed in non-reader section!! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 3 locks held by libvirtd/802: #0: ffff9321e3f58148 (&mm->mmap_sem#2){++++}, at: do_mprotect_pkey+0xe1/0x3e0 #1: ffffffff91ae6160 (mmu_notifier_invalidate_range_start){+.+.}, at: change_p4d_range+0x5fa/0x800 #2: ffffffff91ae6e08 (srcu){....}, at: __mmu_notifier_invalidate_range_start+0x178/0x460 stack backtrace: CPU: 7 PID: 802 Comm: libvirtd Tainted: G I 5.6.0-rc6-next-20200317+ #2 Hardware name: HP ProLiant BL460c Gen8, BIOS I31 11/02/2014 Call Trace: dump_stack+0xa4/0xfe lockdep_rcu_suspicious+0xeb/0xf5 __mmu_notifier_invalidate_range_start+0x3ff/0x460 change_p4d_range+0x746/0x800 change_protection+0x1df/0x300 mprotect_fixup+0x245/0x3e0 do_mprotect_pkey+0x23b/0x3e0 __x64_sys_mprotect+0x51/0x70 do_syscall_64+0x91/0xae8 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Link: http://lkml.kernel.org/r/20200317175640.2047-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Michal Hocko
|
12e967fd8e |
mm: do not allow MADV_PAGEOUT for CoW pages
Jann has brought up a very interesting point [1]. While shared pages
are excluded from MADV_PAGEOUT normally, CoW pages can be easily
reclaimed that way. This can lead to all sorts of hard to debug
problems. E.g. performance problems outlined by Daniel [2].
There are runtime environments where there is a substantial memory
shared among security domains via CoW memory and a easy to reclaim way
of that memory, which MADV_{COLD,PAGEOUT} offers, can lead to either
performance degradation in for the parent process which might be more
privileged or even open side channel attacks.
The feasibility of the latter is not really clear to me TBH but there is
no real reason for exposure at this stage. It seems there is no real
use case to depend on reclaiming CoW memory via madvise at this stage so
it is much easier to simply disallow it and this is what this patch
does. Put it simply MADV_{PAGEOUT,COLD} can operate only on the
exclusively owned memory which is a straightforward semantic.
[1] http://lkml.kernel.org/r/CAG48ez0G3JkMq61gUmyQAaCq=_TwHbi1XKzWRooxZkv08PQKuw@mail.gmail.com
[2] http://lkml.kernel.org/r/CAKOZueua_v8jHCpmEtTB6f3i9e2YnmX4mqdYVWhV4E=Z-n+zRQ@mail.gmail.com
Fixes:
|
||
|
Chris Down
|
e26733e0d0 |
mm, memcg: throttle allocators based on ancestral memory.high
Prior to this commit, we only directly check the affected cgroup's
memory.high against its usage. However, it's possible that we are being
reclaimed as a result of hitting an ancestor memory.high and should be
penalised based on that, instead.
This patch changes memory.high overage throttling to use the largest
overage in its ancestors when considering how many penalty jiffies to
charge. This makes sure that we penalise poorly behaving cgroups in the
same way regardless of at what level of the hierarchy memory.high was
breached.
Fixes:
|