mm: page_alloc: ignore init_on_free=1 for debug_pagealloc=1
On !ARCH_SUPPORTS_DEBUG_PAGEALLOC (like ia64) debug_pagealloc=1 implies
page_poison=on:
if (page_poisoning_enabled() ||
(!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
debug_pagealloc_enabled()))
static_branch_enable(&_page_poisoning_enabled);
page_poison=on needs to override init_on_free=1.
Before the change it did not work as expected for the following case:
- have PAGE_POISONING=y
- have page_poison unset
- have !ARCH_SUPPORTS_DEBUG_PAGEALLOC arch (like ia64)
- have init_on_free=1
- have debug_pagealloc=1
That way we get both keys enabled:
- static_branch_enable(&init_on_free);
- static_branch_enable(&_page_poisoning_enabled);
which leads to poisoned pages returned for __GFP_ZERO pages.
After the change we execute only:
- static_branch_enable(&_page_poisoning_enabled);
and ignore init_on_free=1.
Link: https://lkml.kernel.org/r/20210329222555.3077928-1-slyfox@gentoo.org Link: https://lkml.org/lkml/2021/3/26/443 Fixes: 016c9a64fda9 ("mm, page_poison: use static key more efficiently") Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
net: page_pool: use alloc_pages_bulk in refill code path
There are cases where the page_pool need to refill with pages from the
page allocator. Some workloads cause the page_pool to release pages
instead of recycling these pages.
For these workload it can improve performance to bulk alloc pages from the
page-allocator to refill the alloc cache.
For XDP-redirect workload with 100G mlx5 driver (that use page_pool)
redirecting xdp_frame packets into a veth, that does XDP_PASS to create an
SKB from the xdp_frame, which then cannot return the page to the
page_pool.
Performance results under GitHub xdp-project[1]:
[1] https://github.com/xdp-project/xdp-project/blob/master/areas/mem/page_pool06_alloc_pages_bulk.org
Mel: The patch "net: page_pool: convert to use alloc_pages_bulk_array
variant" was squashed with this patch. From the test page, the array
variant was superior with one of the test results as follows.
Kernel XDP stats CPU pps Delta
Baseline XDP-RX CPU total 3,771,046 n/a
List XDP-RX CPU total 3,940,242 +4.49%
Array XDP-RX CPU total 4,249,224 +12.68%
Link: https://lkml.kernel.org/r/20210325114228.27719-10-mgorman@techsingularity.net Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: David Miller <davem@davemloft.net> Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Chuck Lever [Fri, 30 Apr 2021 06:02:01 +0000 (23:02 -0700)]
SUNRPC: refresh rq_pages using a bulk page allocator
Reduce the rate at which nfsd threads hammer on the page allocator. This
improves throughput scalability by enabling the threads to run more
independently of each other.
[mgorman: Update interpretation of alloc_pages_bulk return value]
Link: https://lkml.kernel.org/r/20210325114228.27719-8-mgorman@techsingularity.net Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Miller <davem@davemloft.net> Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The patches change SUNRPC to invoke the array-based bulk allocator
instead of alloc_page().
The micro-benchmark results are promising. I ran a mixture of 256KB
reads and writes over NFSv3. The server's kernel is built with KASAN
enabled, so the comparison is exaggerated but I believe it is still
valid.
I instrumented svc_recv() to measure the latency of each call to
svc_alloc_arg() and report it via a trace point. The following results
are averages across the trace events.
Single page: 25.007 us per call over 532,571 calls
Bulk list: 6.258 us per call over 517,034 calls
Bulk array: 4.590 us per call over 517,442 calls
This patch (of 2)
Refactor:
I'm about to use the loop variable @i for something else.
As far as the "i++" is concerned, that is a post-increment. The
value of @i is not used subsequently, so the increment operator
is unnecessary and can be removed.
Also note that nfsd_read_actor() was renamed nfsd_splice_actor()
by commit e2dcdb477d84 ("sendfile: convert nfsd to
splice_direct_to_actor()").
Link: https://lkml.kernel.org/r/20210325114228.27719-7-mgorman@techsingularity.net Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Miller <davem@davemloft.net> Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc: optimize code layout for __alloc_pages_bulk
Looking at perf-report and ASM-code for __alloc_pages_bulk() it is clear
that the code activated is suboptimal. The compiler guesses wrong and
places unlikely code at the beginning. Due to the use of WARN_ON_ONCE()
macro the UD2 asm instruction is added to the code, which confuse the
I-cache prefetcher in the CPU.
[mgorman@techsingularity.net: minor changes and rebasing]
Link: https://lkml.kernel.org/r/20210325114228.27719-5-mgorman@techsingularity.net Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Acked-By: Vlastimil Babka <vbabka@suse.cz> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: David Miller <davem@davemloft.net> Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc: add an array-based interface to the bulk page allocator
The proposed callers for the bulk allocator store pages from the bulk
allocator in an array. This patch adds an array-based interface to the
API to avoid multiple list iterations. The page list interface is
preserved to avoid requiring all users of the bulk API to allocate and
manage enough storage to store the pages.
[akpm@linux-foundation.org: remove now unused local `allocated']
Link: https://lkml.kernel.org/r/20210325114228.27719-4-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: David Miller <davem@davemloft.net> Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds a new page allocator interface via alloc_pages_bulk, and
__alloc_pages_bulk_nodemask. A caller requests a number of pages to be
allocated and added to a list.
The API is not guaranteed to return the requested number of pages and
may fail if the preferred allocation zone has limited free memory, the
cpuset changes during the allocation or page debugging decides to fail
an allocation. It's up to the caller to request more pages in batch if
necessary.
Note that this implementation is not very efficient and could be
improved but it would require refactoring. The intent is to make it
available early to determine what semantics are required by different
callers. Once the full semantics are nailed down, it can be refactored.
[mgorman@techsingularity.net: fix alloc_pages_bulk() return type, per Matthew] Link: https://lkml.kernel.org/r/20210325123713.GQ3697@techsingularity.net
[mgorman@techsingularity.net: fix uninit var warning] Link: https://lkml.kernel.org/r/20210330114847.GX3697@techsingularity.net
[mgorman@techsingularity.net: fix comment, per Vlastimil] Link: https://lkml.kernel.org/r/20210412110255.GV3697@techsingularity.net Link: https://lkml.kernel.org/r/20210325114228.27719-3-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Tested-by: Colin Ian King <colin.king@canonical.com> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: David Miller <davem@davemloft.net> Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Introduce a bulk order-0 page allocator with two in-tree users", v6.
This series introduces a bulk order-0 page allocator with sunrpc and the
network page pool being the first users. The implementation is not
efficient as semantics needed to be ironed out first. If no other
semantic changes are needed, it can be made more efficient. Despite that,
this is a performance-related for users that require multiple pages for an
operation without multiple round-trips to the page allocator. Quoting the
last patch for the high-speed networking use-case
Kernel XDP stats CPU pps Delta
Baseline XDP-RX CPU total 3,771,046 n/a
List XDP-RX CPU total 3,940,242 +4.49%
Array XDP-RX CPU total 4,249,224 +12.68%
Via the SUNRPC traces of svc_alloc_arg()
Single page: 25.007 us per call over 532,571 calls
Bulk list: 6.258 us per call over 517,034 calls
Bulk array: 4.590 us per call over 517,442 calls
Both potential users in this series are corner cases (NFS and high-speed
networks) so it is unlikely that most users will see any benefit in the
short term. Other potential other users are batch allocations for page
cache readahead, fault around and SLUB allocations when high-order pages
are unavailable. It's unknown how much benefit would be seen by
converting multiple page allocation calls to a single batch or what
difference it may make to headline performance.
Light testing of my own running dbench over NFS passed. Chuck and Jesper
conducted their own tests and details are included in the changelogs.
Patch 1 renames a variable name that is particularly unpopular
Patch 2 adds a bulk page allocator
Patch 3 adds an array-based version of the bulk allocator
Patches 4-5 adds micro-optimisations to the implementation
Patches 6-7 SUNRPC user
Patches 8-9 Network page_pool user
This patch (of 9):
Review feedback of the bulk allocator twice found problems with "alloced"
being a counter for pages allocated. The naming was based on the API name
"alloc" and was based on the idea that verbal communication about malloc
tends to use the fake word "malloced" instead of the fake word mallocated.
To be consistent, this preparation patch renames alloced to allocated in
rmqueue_bulk so the bulk allocator and per-cpu allocator use similar names
when the bulk allocator is introduced.
Link: https://lkml.kernel.org/r/20210325114228.27719-1-mgorman@techsingularity.net Link: https://lkml.kernel.org/r/20210325114228.27719-2-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kefeng Wang [Fri, 30 Apr 2021 06:01:36 +0000 (23:01 -0700)]
mm, page_alloc: avoid page_to_pfn() in move_freepages()
The start_pfn and end_pfn are already available in move_freepages_block(),
there is no need to go back and forth between page and pfn in
move_freepages and move_freepages_block, and pfn_valid_within() should
validate pfn first before touching the page.
Link: https://lkml.kernel.org/r/20210323131215.934472-1-liushixin2@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Liu Shixin <liushixin2@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 448d2250adbd0701 ("ia64: make SPARSEMEM default and disable
DISCONTIGMEM") removed the last enabler of ARCH_DISCONTIGMEM_DEFAULT,
hence the memory model can no longer default to DISCONTIGMEM_MANUAL.
Link: https://lkml.kernel.org/r/20210312141208.3465520-1-geert@linux-m68k.org Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Minchan Kim [Fri, 30 Apr 2021 06:01:30 +0000 (23:01 -0700)]
mm: page_alloc: dump migrate-failed pages
Currently, debugging CMA allocation failures is quite limited. The most
common source of these failures seems to be page migration which doesn't
provide any useful information on the reason of the failure by itself.
alloc_contig_range can report those failures as it holds a list of
migrate-failed pages.
The information logged by dump_page() has already proven helpful for
debugging allocation issues, like identifying long-term pinnings on
ZONE_MOVABLE or MIGRATE_CMA.
Let's use the dynamic debugging infrastructure, such that we avoid
flooding the logs and creating a lot of noise on frequent
alloc_contig_range() calls. This information is helpful for debugging
only.
There are two ifdefery conditions to support common dyndbg options:
- CONFIG_DYNAMIC_DEBUG_CORE && DYNAMIC_DEBUG_MODULE
It aims for supporting the feature with only specific file with
adding ccflags.
- CONFIG_DYNAMIC_DEBUG
It aims for supporting the feature with system wide globally.
A simple example to enable the feature:
Admin could enable the dump like this(by default, disabled)
A concern is utility functions in dump_page use inconsistent
loglevels. In the future, we might want to make the loglevels
used inside dump_page() consistent and eventually rework the way
we log the information here. See [1].
Link: https://lkml.kernel.org/r/20210311194042.825152-1-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: John Dias <joaodias@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jason Baron <jbaron@akamai.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sphinx interprets the Return section as a list and complains about it.
Turn it into a sentence and move it to the end of the kernel-doc to fit
the kernel-doc style.
Link: https://lkml.kernel.org/r/20210225150642.2582252-8-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc: combine __alloc_pages and __alloc_pages_nodemask
There are only two callers of __alloc_pages() so prune the thicket of
alloc_page variants by combining the two functions together. Current
callers of __alloc_pages() simply add an extra 'NULL' parameter and
current callers of __alloc_pages_nodemask() call __alloc_pages() instead.
Link: https://lkml.kernel.org/r/20210225150642.2582252-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Rationalise __alloc_pages wrappers", v3.
I was poking around the __alloc_pages variants trying to understand why
they each exist, and couldn't really find a good justification for keeping
__alloc_pages and __alloc_pages_nodemask as separate functions. That led
to getting rid of alloc_pages_current() and then I noticed the
documentation was bad, and then I noticed the mempolicy documentation
wasn't included.
Anyway, this is all cleanups & doc fixes.
This patch (of 7):
We have two masks involved -- the nodemask and the gfp mask, so alloc_mask
is an unclear name.
Link: https://lkml.kernel.org/r/20210225150642.2582252-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The naming convention used in include/linux/page-flags-layout.h:
*_SHIFT: the number of bits trying to allocate
*_WIDTH: the number of bits successfully allocated
So when it comes to LAST_CPUPID_WIDTH, we need to check whether all
previous *_WIDTH and LAST_CPUPID_SHIFT can fit into page flags. This
means we need to use NODES_WIDTH, not NODES_SHIFT.
Link: https://lkml.kernel.org/r/20210303071609.797782-1-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Minchan Kim [Fri, 30 Apr 2021 06:01:01 +0000 (23:01 -0700)]
mm: remove lru_add_drain_all in alloc_contig_range
__alloc_contig_migrate_range already has lru_add_drain_all call via
migrate_prep. It's necessary to move LRU taget pages into LRU list to be
able to isolated. However, lru_add_drain_all call after
__alloc_contig_migrate_range is pointless since it has changed source page
freeing from putback_lru_pages to put_page[1].
This patch removes it.
[1] 6a24a175e594, ("mm: use put_page() to free page instead of putback_lru_page()"
Link: https://lkml.kernel.org/r/20210303204512.2863087-1-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc: drop pr_info_ratelimited() in alloc_contig_range()
The information that some PFNs are busy is:
a) not helpful for ordinary users: we don't even know *who* called
alloc_contig_range(). This is certainly not worth a pr_info.*().
b) not really helpful for debugging: we don't have any details *why*
these PFNs are busy, and that is what we usually care about.
c) not complete: there are other cases where we fail alloc_contig_range()
using different paths that are not getting recorded.
For example, we reach this path once we succeeded in isolating pageblocks,
but failed to migrate some pages - which can happen easily on ZONE_NORMAL
(i.e., has_unmovable_pages() is racy) but also on ZONE_MOVABLE i.e., we
would have to retry longer to migrate).
For example via virtio-mem when unplugging memory, we can create quite
some noise (especially with ZONE_NORMAL) that is not of interest to users
- it's expected that some allocations may fail as memory is busy.
Let's just drop that pr_info_ratelimit() and rather implement a dynamic
debugging mechanism in the future that can give us a better reason why
alloc_contig_range() failed on specific pages.
Link: https://lkml.kernel.org/r/20210301150945.77012-1-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add the irq_work_queue() call stack into the KASAN auxiliary stack in
order to improve KASAN reports. this will let us know where the irq work
be queued.
Currently, KASAN-KUnit tests can check that a particular annotated part of
code causes a KASAN report. However, they do not check that no unwanted
reports happen between the annotated parts.
This patch implements these checks.
It is done by setting report_data.report_found to false in
kasan_test_init() and at the end of KUNIT_EXPECT_KASAN_FAIL() and then
checking that it remains false at the beginning of
KUNIT_EXPECT_KASAN_FAIL() and in kasan_test_exit().
kunit_add_named_resource() call is moved to kasan_test_init(), and the
value of fail_data.report_expected is kept as false in between
KUNIT_EXPECT_KASAN_FAIL() annotations for consistency.
Link: https://lkml.kernel.org/r/48079c52cc329fbc52f4386996598d58022fb872.1617207873.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Walter Wu [Fri, 30 Apr 2021 06:00:45 +0000 (23:00 -0700)]
kasan: record task_work_add() call stack
Why record task_work_add() call stack? Syzbot reports many use-after-free
issues for task_work, see [1]. After seeing the free stack and the
current auxiliary stack, we think they are useless, we don't know where
the work was registered. This work may be the free call stack, so we miss
the root cause and don't solve the use-after-free.
Add the task_work_add() call stack into the KASAN auxiliary stack in order
to improve KASAN reports. It helps programmers solve use-after-free
issues.
kasan, mm: integrate slab init_on_free with HW_TAGS
This change uses the previously added memory initialization feature of
HW_TAGS KASAN routines for slab memory when init_on_free is enabled.
With this change, memory initialization memset() is no longer called when
both HW_TAGS KASAN and init_on_free are enabled. Instead, memory is
initialized in KASAN runtime.
For SLUB, the memory initialization memset() is moved into
slab_free_hook() that currently directly follows the initialization loop.
A new argument is added to slab_free_hook() that indicates whether to
initialize the memory or not.
To avoid discrepancies with which memory gets initialized that can be
caused by future changes, both KASAN hook and initialization memset() are
put together and a warning comment is added.
Combining setting allocation tags with memory initialization improves
HW_TAGS KASAN performance when init_on_free is enabled.
Link: https://lkml.kernel.org/r/190fd15c1886654afdec0d19ebebd5ade665b601.1615296150.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kasan, mm: integrate slab init_on_alloc with HW_TAGS
This change uses the previously added memory initialization feature of
HW_TAGS KASAN routines for slab memory when init_on_alloc is enabled.
With this change, memory initialization memset() is no longer called when
both HW_TAGS KASAN and init_on_alloc are enabled. Instead, memory is
initialized in KASAN runtime.
The memory initialization memset() is moved into slab_post_alloc_hook()
that currently directly follows the initialization loop. A new argument
is added to slab_post_alloc_hook() that indicates whether to initialize
the memory or not.
To avoid discrepancies with which memory gets initialized that can be
caused by future changes, both KASAN hook and initialization memset() are
put together and a warning comment is added.
Combining setting allocation tags with memory initialization improves
HW_TAGS KASAN performance when init_on_alloc is enabled.
Link: https://lkml.kernel.org/r/c1292aeb5d519da221ec74a0684a949b027d7720.1615296150.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change uses the previously added memory initialization feature of
HW_TAGS KASAN routines for page_alloc memory when init_on_alloc/free is
enabled.
With this change, kernel_init_free_pages() is no longer called when both
HW_TAGS KASAN and init_on_alloc/free are enabled. Instead, memory is
initialized in KASAN runtime.
To avoid discrepancies with which memory gets initialized that can be
caused by future changes, both KASAN and kernel_init_free_pages() hooks
are put together and a warning comment is added.
This patch changes the order in which memory initialization and page
poisoning hooks are called. This doesn't lead to any side-effects, as
whenever page poisoning is enabled, memory initialization gets disabled.
Combining setting allocation tags with memory initialization improves
HW_TAGS KASAN performance when init_on_alloc/free is enabled.
[andreyknvl@google.com: fix for "integrate page_alloc init with HW_TAGS"] Link: https://lkml.kernel.org/r/65b6028dea2e9a6e8e2cb779b5115c09457363fc.1617122211.git.andreyknvl@google.com Link: https://lkml.kernel.org/r/e77f0d5b1b20658ef0b8288625c74c2b3690e725.1615296150.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Tested-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Sergei Trofimovich <slyfox@gentoo.org> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arm64: kasan: allow to init memory when setting tags
Patch series "kasan: integrate with init_on_alloc/free", v3.
This patch series integrates HW_TAGS KASAN with init_on_alloc/free by
initializing memory via the same arm64 instruction that sets memory tags.
This is expected to improve HW_TAGS KASAN performance when
init_on_alloc/free is enabled. The exact perfomance numbers are unknown
as MTE-enabled hardware doesn't exist yet.
This patch (of 5):
This change adds an argument to mte_set_mem_tag_range() that allows to
enable memory initialization when settinh the allocation tags. The
implementation uses stzg instruction instead of stg when this argument
indicates to initialize memory.
Combining setting allocation tags with memory initialization will improve
HW_TAGS KASAN performance when init_on_alloc/free is enabled.
This change doesn't integrate memory initialization with KASAN, this is
done is subsequent patches in this series.
Link: https://lkml.kernel.org/r/cover.1615296150.git.andreyknvl@google.com Link: https://lkml.kernel.org/r/d04ae90cc36be3fe246ea8025e5085495681c3d7.1615296150.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Marco Elver <elver@google.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> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm, kasan: don't poison boot memory with tag-based modes
During boot, all non-reserved memblock memory is exposed to page_alloc via
memblock_free_pages->__free_pages_core(). This results in
kasan_free_pages() being called, which poisons that memory.
Poisoning all that memory lengthens boot time. The most noticeable effect
is observed with the HW_TAGS mode. A boot-time impact may potentially
also affect systems with large amount of RAM.
This patch changes the tag-based modes to not poison the memory during the
memblock->page_alloc transition.
An exception is made for KASAN_GENERIC. Since it marks all new memory as
accessible, not poisoning the memory released from memblock will lead to
KASAN missing invalid boot-time accesses to that memory.
With KASAN_SW_TAGS, as it uses the invalid 0xFE tag as the default tag for
all memory, it won't miss bad boot-time accesses even if the poisoning of
memblock memory is removed.
With KASAN_HW_TAGS, the default memory tags values are unspecified.
Therefore, if memblock poisoning is removed, this KASAN mode will miss the
mentioned type of boot-time bugs with a 1/16 probability. This is taken
as an acceptable trafe-off.
Internally, the poisoning is removed as follows. __free_pages_core() is
used when exposing fresh memory during system boot and when onlining
memory during hotplug. This patch adds a new FPI_SKIP_KASAN_POISON flag
and passes it to __free_pages_ok() through free_pages_prepare() from
__free_pages_core(). If FPI_SKIP_KASAN_POISON is set, kasan_free_pages()
is not called.
All memory allocated normally when the boot is over keeps getting poisoned
as usual.
Link: https://lkml.kernel.org/r/a0570dc1e3a8f39a55aa343a1fc08cd5c2d4cad6.1613692950.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Marco Elver <elver@google.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kasan: initialize shadow to TAG_INVALID for SW_TAGS
Currently, KASAN_SW_TAGS uses 0xFF as the default tag value for
unallocated memory. The underlying idea is that since that memory hasn't
been allocated yet, it's only supposed to be dereferenced through a
pointer with the native 0xFF tag.
While this is a good idea in terms on consistency, practically it doesn't
bring any benefit. Since the 0xFF pointer tag is a match-all tag, it
doesn't matter what tag the accessed memory has. No accesses through
0xFF-tagged pointers are considered buggy by KASAN.
This patch changes the default tag value for unallocated memory to 0xFE,
which is the tag KASAN uses for inaccessible memory. This doesn't affect
accesses through 0xFF-tagged pointer to this memory, but this allows KASAN
to detect wild and large out-of-bounds invalid memory accesses through
otherwise-tagged pointers.
This is a prepatory patch for the next one, which changes the tag-based
KASAN modes to not poison the boot memory.
Link: https://lkml.kernel.org/r/c8e93571c18b3528aac5eb33ade213bf133d10ad.1613692950.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Marco Elver <elver@google.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kasan: fix kasan_byte_accessible() to be consistent with actual checks
We can sometimes end up with kasan_byte_accessible() being called on
non-slab memory. For example ksize() and krealloc() may end up calling it
on KFENCE allocated memory. In this case the memory will be tagged with
KASAN_SHADOW_INIT, which a subsequent patch ("kasan: initialize shadow to
TAG_INVALID for SW_TAGS") will set to the same value as KASAN_TAG_INVALID,
causing kasan_byte_accessible() to fail when called on non-slab memory.
This highlighted the fact that the check in kasan_byte_accessible() was
inconsistent with checks as implemented for loads and stores
(kasan_check_range() in SW tags mode and hardware-implemented checks in HW
tags mode). kasan_check_range() does not have a check for
KASAN_TAG_INVALID, and instead has a comparison against
KASAN_SHADOW_START. In HW tags mode, we do not have either, but we do set
TCR_EL1.TCMA which corresponds with the comparison against
KASAN_TAG_KERNEL.
Therefore, update kasan_byte_accessible() for both SW and HW tags modes to
correspond with the respective checks on loads and stores.
Link: https://linux-review.googlesource.com/id/Ic6d40803c57dcc6331bd97fbb9a60b0d38a65a36 Link: https://lkml.kernel.org/r/20210405220647.1965262-1-pcc@google.com Signed-off-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Zhiyuan Dai [Fri, 30 Apr 2021 05:59:43 +0000 (22:59 -0700)]
mm/kasan: switch from strlcpy to strscpy
strlcpy is marked as deprecated in Documentation/process/deprecated.rst,
and there is no functional difference when the caller expects truncation
(when not checking the return value). strscpy is relatively better as it
also avoids scanning the whole source string.
Link: https://lkml.kernel.org/r/1613970647-23272-1-git-send-email-daizhiyuan@phytium.com.cn Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn> Acked-by: Alexander Potapenko <glider@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The script './scripts/kernel-doc -none ./include/linux/pagewalk.h' reports:
include/linux/pagewalk.h:37: warning: cannot understand function prototype: 'struct mm_walk_ops '
include/linux/pagewalk.h:85: warning: cannot understand function prototype: 'struct mm_walk '
A kernel-doc description for a structure requires to prefix the struct
name with the keyword 'struct'. So, do that such that no further
kernel-doc warnings are reported for this file.
Link: https://lkml.kernel.org/r/20210322122542.15072-3-lukas.bulwahn@gmail.com Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ralf Ramsauer <ralf.ramsauer@oth-regensburg.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MAINTAINERS: assign pagewalk.h to MEMORY MANAGEMENT
Patch series "kernel-doc and MAINTAINERS clean-up".
Roughly 900 warnings of about 21.000 kernel-doc warnings in the kernel
tree warn with 'cannot understand function prototype:', i.e., the
kernel-doc parser cannot parse the function's signature. The majority,
about 600 cases of those, are just struct definitions following the
kernel-doc description. Further, spot-check investigations suggest that
the authors of the specific kernel-doc descriptions simply were not
aware that the general format for a kernel-doc description for a
structure requires to prefix the struct name with the keyword 'struct',
as in 'struct struct_name - Brief description.'. Details on kernel-doc
are at the Link below.
Without the struct keyword, kernel-doc does not check if the kernel-doc
description fits to the actual struct definition in the source code.
Fortunately, in roughly a quarter of these cases, the kernel-doc
description is actually complete wrt. its corresponding struct
definition. So, the trivial change adding the struct keyword will allow
us to keep the kernel-doc descriptions more consistent for future
changes, by checking for new kernel-doc warnings.
Also, some of the files in ./include/ are not assigned to a specific
MAINTAINERS section and hence have no dedicated maintainer. So, if
needed, the files in ./include/ are also assigned to the fitting
MAINTAINERS section, as I need to identify whom to send the clean-up
patch anyway.
Here is the change from this kernel-doc janitorial work in the
./include/ directory for MEMORY MANAGEMENT.
This patch (of 2):
Commit 7de01c5d6089 ("mm: split out a new pagewalk.h header from mm.h")
adds a new file in ./include/linux, but misses to update MAINTAINERS
accordingly. Hence,
Instead of keeping open-coded style, move the code related to preloading
into a separate function. Therefore introduce the preload_this_cpu_lock()
routine that prelaods a current CPU with one extra vmap_area object.
There is no functional change as a result of this patch.
Link: https://lkml.kernel.org/r/20210402202237.20334-4-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vm/test_vmalloc.sh: adapt for updated driver interface
A 'single_cpu_test' parameter is odd and it does not exist anymore.
Instead there was introduced a 'nr_threads' one. If it is not set it
behaves as the former parameter.
That is why update a "stress mode" according to this change specifying
number of workers which are equal to number of CPUs. Also update an
output of help message based on a new interface.
Link: https://lkml.kernel.org/r/20210402202237.20334-3-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Hillf Danton <hdanton@sina.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/test_vmalloc.c: add a new 'nr_threads' parameter
By using this parameter we can specify how many workers are created to
perform vmalloc tests. By default it is one CPU. The maximum value is
set to 1024.
As a result of this change a 'single_cpu_test' one becomes obsolete,
therefore it is no longer needed.
[urezki@gmail.com: extend max value of nr_threads parameter] Link: https://lkml.kernel.org/r/20210406124536.19658-1-urezki@gmail.com Link: https://lkml.kernel.org/r/20210402202237.20334-2-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove two test cases related to kvfree_rcu() and SLAB. Those are
considered as redundant now, because similar test functionality has
recently been introduced in the "rcuscale" RCU test-suite.
Link: https://lkml.kernel.org/r/20210402202237.20334-1-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here Process 1 is in purge path and it does list_del_rcu on vmap_block and
later frees the vmap_area, since Process 2 was holding the rcu lock at
this time vmap_block will still be present in and Process 2 accesse it and
thereby it tries to access vmap_area of that vmap_block which was already
freed by Process 1 and this results in use after free.
Fix this by adding a check for vb->dirty before accessing vmap_area
structure since vb->dirty will be set to VMAP_BBMAP_BITS in purge path
checking for this will prevent the use after free.
There are several reasons why a vmalloc can fail, virtual space exhausted,
page array allocation failure, page allocation failure, and kernel page
table allocation failure.
Add distinct warning messages for the main causes of failure, with some
added information like page order or allocation size where applicable.
Nicholas Piggin [Fri, 30 Apr 2021 05:58:49 +0000 (22:58 -0700)]
mm/vmalloc: hugepage vmalloc mappings
Support huge page vmalloc mappings. Config option HAVE_ARCH_HUGE_VMALLOC
enables support on architectures that define HAVE_ARCH_HUGE_VMAP and
supports PMD sized vmap mappings.
vmalloc will attempt to allocate PMD-sized pages if allocating PMD size or
larger, and fall back to small pages if that was unsuccessful.
Architectures must ensure that any arch specific vmalloc allocations that
require PAGE_SIZE mappings (e.g., module allocations vs strict module rwx)
use the VM_NOHUGE flag to inhibit larger mappings.
This can result in more internal fragmentation and memory overhead for a
given allocation, an option nohugevmalloc is added to disable at boot.
[colin.king@canonical.com: fix read of uninitialized pointer area] Link: https://lkml.kernel.org/r/20210318155955.18220-1-colin.king@canonical.com Link: https://lkml.kernel.org/r/20210317062402.533919-14-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ding Tianhong <dingtianhong@huawei.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nicholas Piggin [Fri, 30 Apr 2021 05:58:46 +0000 (22:58 -0700)]
mm/vmalloc: add vmap_range_noflush variant
As a side-effect, the order of flush_cache_vmap() and
arch_sync_kernel_mappings() calls are switched, but that now matches the
other callers in this file.
Link: https://lkml.kernel.org/r/20210317062402.533919-13-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ding Tianhong <dingtianhong@huawei.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nicholas Piggin [Fri, 30 Apr 2021 05:58:26 +0000 (22:58 -0700)]
mm: HUGE_VMAP arch support cleanup
This changes the awkward approach where architectures provide init
functions to determine which levels they can provide large mappings for,
to one where the arch is queried for each call.
This removes code and indirection, and allows constant-folding of dead
code for unsupported levels.
This also adds a prot argument to the arch query. This is unused
currently but could help with some architectures (e.g., some powerpc
processors can't map uncacheable memory with large pages).
Link: https://lkml.kernel.org/r/20210317062402.533919-7-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Ding Tianhong <dingtianhong@huawei.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Cc: Will Deacon <will@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Russell King <linux@armlinux.org.uk> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nicholas Piggin [Fri, 30 Apr 2021 05:58:16 +0000 (22:58 -0700)]
mm: apply_to_pte_range warn and fail if a large pte is encountered
apply_to_pte_range might mistake a large pte for bad, or treat it as a
page table, resulting in a crash or corruption. Add a test to warn and
return error if large entries are found.
Link: https://lkml.kernel.org/r/20210317062402.533919-4-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ding Tianhong <dingtianhong@huawei.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nicholas Piggin [Fri, 30 Apr 2021 05:58:13 +0000 (22:58 -0700)]
mm/vmalloc: fix HUGE_VMAP regression by enabling huge pages in vmalloc_to_page
vmalloc_to_page returns NULL for addresses mapped by larger pages[*].
Whether or not a vmap is huge depends on the architecture details,
alignments, boot options, etc., which the caller can not be expected to
know. Therefore HUGE_VMAP is a regression for vmalloc_to_page.
This change teaches vmalloc_to_page about larger pages, and returns the
struct page that corresponds to the offset within the large page. This
makes the API agnostic to mapping implementation details.
[*] As explained by commit 75e6da1859a5f ("mm/vmalloc.c: huge-vmap:
fail gracefully on unexpected huge vmap mappings")
[npiggin@gmail.com: sparc32: add stub pud_page define for walking huge vmalloc page tables] Link: https://lkml.kernel.org/r/20210324232825.1157363-1-npiggin@gmail.com Link: https://lkml.kernel.org/r/20210317062402.533919-3-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ding Tianhong <dingtianhong@huawei.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nicholas Piggin [Fri, 30 Apr 2021 05:58:10 +0000 (22:58 -0700)]
ARM: mm: add missing pud_page define to 2-level page tables
Patch series "huge vmalloc mappings", v13.
The kernel virtual mapping layer grew support for mapping memory with >
PAGE_SIZE ptes with commit a8ff1e199667 ("lib/ioremap.c: add huge I/O
map capability interfaces"), and implemented support for using those
huge page mappings with ioremap.
According to the submission, the use-case is mapping very large
non-volatile memory devices, which could be GB or TB:
The benefit is said to be in the overhead of maintaining the mapping,
perhaps both in memory overhead and setup / teardown time. Memory
overhead for the mapping with a 4kB page and 8 byte page table is 2GB
per TB of mapping, down to 4MB / TB with 2MB pages.
The same huge page vmap infrastructure can be quite easily adapted and
used for mapping vmalloc memory pages without more complexity for arch
or core vmap code. However unlike ioremap, vmalloc page table overhead
is not a real problem, so the advantage to justify this is performance.
Several of the most structures in the kernel (e.g., vfs and network hash
tables) are allocated with vmalloc on NUMA machines, in order to
distribute access bandwidth over the machine. Mapping these with larger
pages can improve TLB usage significantly, for example this reduces TLB
misses by nearly 30x on a `git diff` workload on a 2-node POWER9 (59,800
-> 2,100) and reduces CPU cycles by 0.54%, due to vfs hashes being
allocated with 2MB pages.
[ Other numbers?
- The difference is even larger in a guest due to more costly TLB
misses.
- Eric Dumazet was keen on the network hash performance possibilities.
- Other archs? Ding was doing x86 testing. ]
The kernel module allocator also uses vmalloc to map module images even on
non-NUMA, which can result in high iTLB pressure on highly modular distro
type of kernels. This series does not implement huge mappings for modules
yet, but it's a step along the way. Rick Edgecombe was looking at that
IIRC.
The per-cpu allocator similarly might be able to take advantage of this.
Also on the todo list.
The disadvantages of this I can see are:
* Memory fragmentation can waste some physical memory because it will
attempt to allocate larger pages to fit the required size, rounding up
(once the requested size is >= 2MB).
- I don't see it being a big problem in practice unless some user
crops up that allocates thousands of 2.5MB ranges. We can tewak
heuristics a bit there if needed to reduce peak waste.
* Less granular mappings can make the NUMA distribution less balanced.
- Similar to the above.
- Could also allocate all major system hashes with one allocation
up-front and spread them all across the one block, which should help
overall NUMA distribution and reduce fragmentation waste.
* Callers might expect something about the underlying allocated pages.
- Tried to keep the apperance of base PAGE_SIZE pages throughout the
APIs and exposed data structures.
- Added a VM_NO_HUGE_VMAP flag to hammer troublesome cases with.
- Finally, added a nohugevmalloc boot option to turn it off (independent
of nohugeiomap).
This patch (of 14):
ARM uses its own PMD folding scheme which is missing pud_page which should
just pass through to pmd_page. Move this from the 3-level page table to
common header.
Link: https://lkml.kernel.org/r/20210317062402.533919-2-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Ding Tianhong <dingtianhong@huawei.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/vmalloc: use rb_tree instead of list for vread() lookups
vread() has been linearly searching vmap_area_list for looking up vmalloc
areas to read from. These same areas are also tracked by a rb_tree
(vmap_area_root) which offers logarithmic lookup.
This patch modifies vread() to use the rb_tree structure instead of the
list and the speedup for heavy /proc/kcore readers can be pretty
significant. Below are the wall clock measurements of a Python
application that leverages the drgn debugging library to read and
interpret data read from /proc/kcore.
Before the patch:
-----
$ time sudo sdb -e 'dbuf | head 3000 | wc'
(unsigned long)3000
real 0m22.446s
user 0m2.321s
sys 0m20.690s
-----
With the patch:
-----
$ time sudo sdb -e 'dbuf | head 3000 | wc'
(unsigned long)3000
Wang Wensheng [Fri, 30 Apr 2021 05:57:58 +0000 (22:57 -0700)]
mm/sparse: add the missing sparse_buffer_fini() in error branch
sparse_buffer_init() and sparse_buffer_fini() should appear in pair, or a
WARN issue would be through the next time sparse_buffer_init() runs.
Add the missing sparse_buffer_fini() in error branch.
Link: https://lkml.kernel.org/r/20210325113155.118574-1-wangwensheng4@huawei.com Fixes: 462a0690709c ("mm/sparse: add new sparse_init_nid() and sparse_init()") Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Zhiyuan Dai [Fri, 30 Apr 2021 05:57:55 +0000 (22:57 -0700)]
mm/dmapool: switch from strlcpy to strscpy
strlcpy is marked as deprecated in Documentation/process/deprecated.rst,
and there is no functional difference when the caller expects truncation
(when not checking the return value). strscpy is relatively better as it
also avoids scanning the whole source string.
As discussed in [1] this commit was a no-op because the mapping type was
checked in vma_to_resize before move_vma is ever called. This meant that
vm_ops->mremap() would never be called on such mappings. Furthermore,
we've since expanded support of MREMAP_DONTUNMAP to non-anonymous
mappings, and these special mappings are still protected by the existing
check of !VM_DONTEXPAND and !VM_PFNMAP which will result in a -EINVAL.
1. https://lkml.org/lkml/2020/12/28/2340
Link: https://lkml.kernel.org/r/20210323182520.2712101-2-bgeffon@google.com Signed-off-by: Brian Geffon <bgeffon@google.com> Acked-by: Hugh Dickins <hughd@google.com> Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Alejandro Colomar <alx.manpages@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: "Michael S . Tsirkin" <mst@redhat.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Sonny Rao <sonnyrao@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>
Brian Geffon [Fri, 30 Apr 2021 05:57:45 +0000 (22:57 -0700)]
mm: extend MREMAP_DONTUNMAP to non-anonymous mappings
Patch series "mm: Extend MREMAP_DONTUNMAP to non-anonymous mappings", v5.
This patch (of 3):
Currently MREMAP_DONTUNMAP only accepts private anonymous mappings. This
restriction was placed initially for simplicity and not because there
exists a technical reason to do so.
This change will widen the support to include any mappings which are not
VM_DONTEXPAND or VM_PFNMAP. The primary use case is to support
MREMAP_DONTUNMAP on mappings which may have been created from a memfd.
This change will result in mremap(MREMAP_DONTUNMAP) returning -EINVAL if
VM_DONTEXPAND or VM_PFNMAP mappings are specified.
Lokesh Gidra who works on the Android JVM, provided an explanation of how
such a feature will improve Android JVM garbage collection: "Android is
developing a new garbage collector (GC), based on userfaultfd. The
garbage collector will use userfaultfd (uffd) on the java heap during
compaction. On accessing any uncompacted page, the application threads
will find it missing, at which point the thread will create the compacted
page and then use UFFDIO_COPY ioctl to get it mapped and then resume
execution. Before starting this compaction, in a stop-the-world pause the
heap will be mremap(MREMAP_DONTUNMAP) so that the java heap is ready to
receive UFFD_EVENT_PAGEFAULT events after resuming execution.
To speedup mremap operations, pagetable movement was optimized by moving
PUD entries instead of PTE entries [1]. It was necessary as mremap of
even modest sized memory ranges also took several milliseconds, and
stopping the application for that long isn't acceptable in response-time
sensitive cases.
With UFFDIO_CONTINUE feature [2], it will be even more efficient to
implement this GC, particularly the 'non-moveable' portions of the heap.
It will also help in reducing the need to copy (UFFDIO_COPY) the pages.
However, for this to work, the java heap has to be on a 'shared' vma.
Currently MREMAP_DONTUNMAP only supports private anonymous mappings, this
patch will enable using UFFDIO_CONTINUE for the new userfaultfd-based heap
compaction."
NUMA balancing: reduce TLB flush via delaying mapping on hint page fault
With NUMA balancing, in hint page fault handler, the faulting page will be
migrated to the accessing node if necessary. During the migration, TLB
will be shot down on all CPUs that the process has run on recently.
Because in the hint page fault handler, the PTE will be made accessible
before the migration is tried. The overhead of TLB shooting down can be
high, so it's better to be avoided if possible. In fact, if we delay
mapping the page until migration, that can be avoided. This is what this
patch doing.
For the multiple threads applications, it's possible that a page is
accessed by multiple threads almost at the same time. In the original
implementation, because the first thread will install the accessible PTE
before migrating the page, the other threads may access the page directly
before the page is made inaccessible again during migration. While with
the patch, the second thread will go through the page fault handler too.
And because of the PageLRU() checking in the following code path,
the migrate_misplaced_page() will return 0, and the PTE will be made
accessible in the second thread.
This will introduce a little more overhead. But we think the possibility
for a page to be accessed by the multiple threads at the same time is low,
and the overhead difference isn't too large. If this becomes a problem in
some workloads, we need to consider how to reduce the overhead.
To test the patch, we run a test case as follows on a 2-socket Intel
server (1 NUMA node per socket) with 128GB DRAM (64GB per socket).
1. Run a memory eater on NUMA node 1 to use 40GB memory before running
pmbench.
2. Run pmbench (normal accessing pattern) with 8 processes, and 8
threads per process, so there are 64 threads in total. The
working-set size of each process is 8960MB, so the total working-set
size is 8 * 8960MB = 70GB. The CPU of all pmbench processes is bound
to node 1. The pmbench processes will access some DRAM on node 0.
3. After the pmbench processes run for 10 seconds, kill the memory
eater. Now, some pages will be migrated from node 0 to node 1 via
NUMA balancing.
Test results show that, with the patch, the pmbench throughput (page
accesses/s) increases 5.5%. The number of the TLB shootdowns interrupts
reduces 98% (from ~4.7e7 to ~9.7e5) with about 9.2e6 pages (35.8GB)
migrated. From the perf profile, it can be found that the CPU cycles
spent by try_to_unmap() and its callees reduces from 6.02% to 0.47%. That
is, the CPU cycles spent by TLB shooting down decreases greatly.
Link: https://lkml.kernel.org/r/20210408132236.1175607-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: "Matthew Wilcox" <willy@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Michel Lespinasse <walken@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
remap_io_sg claims that the pgprot is pre-verified using an io_mapping,
but actually does not get passed an io_mapping and just uses the pgprot in
the VMA. Remove the apply_to_page_range abuse and just loop over
remap_pfn_range for each segment.
Note: this could use io_mapping_map_user by passing an iomap to
remap_io_sg if the maintainers can verify that the pgprot in the iomap in
the only caller is indeed the desired one here.
Link: https://lkml.kernel.org/r/20210326055505.1424432-5-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a helper that calls remap_pfn_range for an struct io_mapping, relying
on the pgprot pre-validation done when creating the mapping instead of
doing it at runtime.
Link: https://lkml.kernel.org/r/20210326055505.1424432-3-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "add remap_pfn_range_notrack instead of reinventing it in i915", v2.
i915 has some reason to want to avoid the track_pfn_remap overhead in
remap_pfn_range. Add a function to the core VM to do just that rather
than reinventing the functionality poorly in the driver.
Note that the remap_io_sg path does get exercises when using Xorg on my
Thinkpad X1, so this should be considered lightly tested, I've not managed
to hit the remap_io_mapping path at all.
This patch (of 4):
Add a version of remap_pfn_range that does not call track_pfn_range. This
will be used to fix horrible abuses of VM internals in the i915 driver.
Link: https://lkml.kernel.org/r/20210326055505.1424432-1-hch@lst.de Link: https://lkml.kernel.org/r/20210326055505.1424432-2-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adjust the rss_stat tracepoint to print the name of the resident page type
that got updated (e.g. MM_ANONPAGES/MM_FILEPAGES), rather than the numeric
index corresponding to it (the __entry->member value):
Use TRACE_DEFINE_ENUM()/__print_symbolic() logic to map the enum values to
the strings they represent, so that userspace tools can also parse the raw
data correctly.
Link: https://lkml.kernel.org/r/20210310162305.4862-1-ovidiu.panait@windriver.com Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com> Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oscar Salvador [Fri, 30 Apr 2021 05:57:22 +0000 (22:57 -0700)]
x86/vmemmap: optimize for consecutive sections in partial populated PMDs
We can optimize in the case we are adding consecutive sections, so no
memset(PAGE_UNUSED) is needed.
In that case, let us keep track where the unused range of the previous
memory range begins, so we can compare it with start of the range to be
added. If they are equal, we know sections are added consecutively.
For that purpose, let us introduce 'unused_pmd_start', which always holds
the beginning of the unused memory range.
In the case a section does not contiguously follow the previous one, we
know we can memset [unused_pmd_start, PMD_BOUNDARY) with PAGE_UNUSE.
This patch is based on a similar patch by David Hildenbrand:
Link: https://lkml.kernel.org/r/20210309214050.4674-5-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oscar Salvador [Fri, 30 Apr 2021 05:57:19 +0000 (22:57 -0700)]
x86/vmemmap: handle unpopulated sub-pmd ranges
When sizeof(struct page) is not a power of 2, sections do not span a PMD
anymore and so when populating them some parts of the PMD will remain
unused.
Because of this, PMDs will be left behind when depopulating sections since
remove_pmd_table() thinks that those unused parts are still in use.
Fix this by marking the unused parts with PAGE_UNUSED, so memchr_inv()
will do the right thing and will let us free the PMD when the last user of
it is gone.
This patch is based on a similar patch by David Hildenbrand:
[osalvador@suse.de: go back to the ifdef version] Link: https://lkml.kernel.org/r/YGy++mSft7K4u+88@localhost.localdomain Link: https://lkml.kernel.org/r/20210309214050.4674-4-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oscar Salvador [Fri, 30 Apr 2021 05:57:16 +0000 (22:57 -0700)]
x86/vmemmap: drop handling of 1GB vmemmap ranges
There is no code to allocate 1GB pages when mapping the vmemmap range as
this might waste some memory and requires more complexity which is not
really worth.
Drop the dead code both for the aligned and unaligned cases and leave only
the direct map handling.
Link: https://lkml.kernel.org/r/20210309214050.4674-3-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Suggested-by: David Hildenbrand <david@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oscar Salvador [Fri, 30 Apr 2021 05:57:12 +0000 (22:57 -0700)]
x86/vmemmap: drop handling of 4K unaligned vmemmap range
Patch series "Cleanup and fixups for vmemmap handling", v6.
This series contains cleanups to remove dead code that handles unaligned
cases for 4K and 1GB pages (patch#1 and patch#2) when removing the vemmmap
range, and a fix (patch#3) to handle the case when two vmemmap ranges
intersect the same PMD.
This patch (of 4):
remove_pte_table() is prepared to handle the case where either the start
or the end of the range is not PAGE aligned. This cannot actually happen:
__populate_section_memmap enforces the range to be PMD aligned, so as long
as the size of the struct page remains multiple of 8, the vmemmap range
will be aligned to PAGE_SIZE.
Drop the dead code and place a VM_BUG_ON in vmemmap_{populate,free} to
catch nasty cases. Note that the VM_BUG_ON is placed in there because
vmemmap_{populate,free= } is the gate of all removing and freeing page
tables logic.
Link: https://lkml.kernel.org/r/20210309214050.4674-1-osalvador@suse.de Link: https://lkml.kernel.org/r/20210309214050.4674-2-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Suggested-by: David Hildenbrand <david@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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