| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
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."
[1] https://lore.kernel.org/linux-mm/20201215030730.NC3CU98e4%25akpm@linux-foundation.org/
[2] https://lore.kernel.org/linux-mm/20210302000133.272579-1-axelrasmussen@google.com/
Link: https://lkml.kernel.org/r/20210323182520.2712101-1-bgeffon@google.com
Signed-off-by: Brian Geffon <bgeffon@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Tested-by: Lokesh Gidra <lokeshgidra@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: "Kirill A . Shutemov" <kirill@shutemov.name>
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>
|
|
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,
migrate_misplaced_page()
numamigrate_isolate_page()
isolate_lru_page()
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>
|
|
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>
|
|
Add a comment explaining the value of the ISSTATIC parameter, Inform the
reader that this is not a coding style issue.
Link: https://lkml.kernel.org/r/1613964695-17614-1-git-send-email-daizhiyuan@phytium.com.cn
Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Smatch gives the warning:
do_numa_page() warn: assigning (-11) to unsigned variable 'migrated'
Link: https://lkml.kernel.org/r/1614603421-2681-1-git-send-email-wangqing@vivo.com
Signed-off-by: Wang Qing <wangqing@vivo.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When the unsigned page_counter underflows, even just by a few pages, a
cgroup will not be able to run anything afterwards and trigger the OOM
killer in a loop.
Underflows shouldn't happen, but when they do in practice, we may just be
off by a small amount that doesn't interfere with the normal operation -
consequences don't need to be that dire.
Reset the page_counter to 0 upon underflow. We'll issue a warning that
the accounting will be off and then try to keep limping along.
[ We used to do this with the original res_counter, where it was a
more straight-forward correction inside the spinlock section. I
didn't carry it forward into the lockless page counters for
simplicity, but it turns out this is quite useful in practice. ]
Link: https://lkml.kernel.org/r/20210408143155.2679744-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
obj_cgroup_{un}charge_pages()
There is only one user of __memcg_kmem_charge(), so manually inline
__memcg_kmem_charge() to obj_cgroup_charge_pages(). Similarly manually
inline __memcg_kmem_uncharge() into obj_cgroup_uncharge_pages() and call
obj_cgroup_uncharge_pages() in obj_cgroup_release().
This is just code cleanup without any functionality changes.
Link: https://lkml.kernel.org/r/20210319163821.20704-7-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Since Roman's series "The new cgroup slab memory controller" applied.
All slab objects are charged via the new APIs of obj_cgroup. The new
APIs introduce a struct obj_cgroup to charge slab objects. It prevents
long-living objects from pinning the original memory cgroup in the
memory. But there are still some corner objects (e.g. allocations
larger than order-1 page on SLUB) which are not charged via the new
APIs. Those objects (include the pages which are allocated from buddy
allocator directly) are charged as kmem pages which still hold a
reference to the memory cgroup.
We want to reuse the obj_cgroup APIs to charge the kmem pages. If we do
that, we should store an object cgroup pointer to page->memcg_data for
the kmem pages.
Finally, page->memcg_data will have 3 different meanings.
1) For the slab pages, page->memcg_data points to an object cgroups
vector.
2) For the kmem pages (exclude the slab pages), page->memcg_data
points to an object cgroup.
3) For the user pages (e.g. the LRU pages), page->memcg_data points
to a memory cgroup.
We do not change the behavior of page_memcg() and page_memcg_rcu(). They
are also suitable for LRU pages and kmem pages. Why?
Because memory allocations pinning memcgs for a long time - it exists at a
larger scale and is causing recurring problems in the real world: page
cache doesn't get reclaimed for a long time, or is used by the second,
third, fourth, ... instance of the same job that was restarted into a new
cgroup every time. Unreclaimable dying cgroups pile up, waste memory, and
make page reclaim very inefficient.
We can convert LRU pages and most other raw memcg pins to the objcg
direction to fix this problem, and then the page->memcg will always point
to an object cgroup pointer. At that time, LRU pages and kmem pages will
be treated the same. The implementation of page_memcg() will remove the
kmem page check.
This patch aims to charge the kmem pages by using the new APIs of
obj_cgroup. Finally, the page->memcg_data of the kmem page points to an
object cgroup. We can use the __page_objcg() to get the object cgroup
associated with a kmem page. Or we can use page_memcg() to get the memory
cgroup associated with a kmem page, but caller must ensure that the
returned memcg won't be released (e.g. acquire the rcu_read_lock or
css_set_lock).
Link: https://lkml.kernel.org/r/20210401030141.37061-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210319163821.20704-6-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
[songmuchun@bytedance.com: fix forget to obtain the ref to objcg in split_page_memcg]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Just like assignment to ug->memcg, we only need to update ug->dummy_page
if memcg changed. So move it to there. This is a very small
optimization.
Link: https://lkml.kernel.org/r/20210319163821.20704-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
page_memcg() is not suitable for use by page_expected_state() and
page_bad_reason(). Because it can BUG_ON() for the slab pages when
CONFIG_DEBUG_VM is enabled. As neither lru, nor kmem, nor slab page
should have anything left in there by the time the page is freed, what
we care about is whether the value of page->memcg_data is 0. So just
directly access page->memcg_data here.
Link: https://lkml.kernel.org/r/20210319163821.20704-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
We know that the unit of slab object charging is bytes, the unit of kmem
page charging is PAGE_SIZE. If we want to reuse obj_cgroup APIs to
charge the kmem pages, we should pass PAGE_SIZE (as third parameter) to
obj_cgroup_charge(). Because the size is already PAGE_SIZE, we can skip
touch the objcg stock. And obj_cgroup_{un}charge_pages() are introduced
to charge in units of page level.
In the latter patch, we also can reuse those two helpers to charge or
uncharge a number of kernel pages to a object cgroup. This is just a
code movement without any functional changes.
Link: https://lkml.kernel.org/r/20210319163821.20704-3-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "Use obj_cgroup APIs to charge kmem pages", v5.
Since Roman's series "The new cgroup slab memory controller" applied.
All slab objects are charged with the new APIs of obj_cgroup. The new
APIs introduce a struct obj_cgroup to charge slab objects. It prevents
long-living objects from pinning the original memory cgroup in the
memory. But there are still some corner objects (e.g. allocations
larger than order-1 page on SLUB) which are not charged with the new
APIs. Those objects (include the pages which are allocated from buddy
allocator directly) are charged as kmem pages which still hold a
reference to the memory cgroup.
E.g. We know that the kernel stack is charged as kmem pages because the
size of the kernel stack can be greater than 2 pages (e.g. 16KB on
x86_64 or arm64). If we create a thread (suppose the thread stack is
charged to memory cgroup A) and then move it from memory cgroup A to
memory cgroup B. Because the kernel stack of the thread hold a
reference to the memory cgroup A. The thread can pin the memory cgroup
A in the memory even if we remove the cgroup A. If we want to see this
scenario by using the following script. We can see that the system has
added 500 dying cgroups (This is not a real world issue, just a script
to show that the large kmallocs are charged as kmem pages which can pin
the memory cgroup in the memory).
#!/bin/bash
cat /proc/cgroups | grep memory
cd /sys/fs/cgroup/memory
echo 1 > memory.move_charge_at_immigrate
for i in range{1..500}
do
mkdir kmem_test
echo $$ > kmem_test/cgroup.procs
sleep 3600 &
echo $$ > cgroup.procs
echo `cat kmem_test/cgroup.procs` > cgroup.procs
rmdir kmem_test
done
cat /proc/cgroups | grep memory
This patchset aims to make those kmem pages to drop the reference to
memory cgroup by using the APIs of obj_cgroup. Finally, we can see that
the number of the dying cgroups will not increase if we run the above test
script.
This patch (of 7):
The rcu_read_lock/unlock only can guarantee that the memcg will not be
freed, but it cannot guarantee the success of css_get (which is in the
refill_stock when cached memcg changed) to memcg.
rcu_read_lock()
memcg = obj_cgroup_memcg(old)
__memcg_kmem_uncharge(memcg)
refill_stock(memcg)
if (stock->cached != memcg)
// css_get can change the ref counter from 0 back to 1.
css_get(&memcg->css)
rcu_read_unlock()
This fix is very like the commit:
eefbfa7fd678 ("mm: memcg/slab: fix use after free in obj_cgroup_charge")
Fix this by holding a reference to the memcg which is passed to the
__memcg_kmem_uncharge() before calling __memcg_kmem_uncharge().
Link: https://lkml.kernel.org/r/20210319163821.20704-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210319163821.20704-2-songmuchun@bytedance.com
Fixes: 3de7d4f25a74 ("mm: memcg/slab: optimize objcg stock draining")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Currently the kernel adds the page, allocated for swapin, to the
swapcache before charging the page. This is fine but now we want a
per-memcg swapcache stat which is essential for folks who wants to
transparently migrate from cgroup v1's memsw to cgroup v2's memory and
swap counters. In addition charging a page before exposing it to other
parts of the kernel is a step in the right direction.
To correctly maintain the per-memcg swapcache stat, this patch has
adopted to charge the page before adding it to swapcache. One challenge
in this option is the failure case of add_to_swap_cache() on which we
need to undo the mem_cgroup_charge(). Specifically undoing
mem_cgroup_uncharge_swap() is not simple.
To resolve the issue, this patch decouples the charging for swapin pages
from mem_cgroup_charge(). Two new functions are introduced,
mem_cgroup_swapin_charge_page() for just charging the swapin page and
mem_cgroup_swapin_uncharge_swap() for uncharging the swap slot once the
page has been successfully added to the swapcache.
[shakeelb@google.com: set page->private before calling swap_readpage]
Link: https://lkml.kernel.org/r/20210318015959.2986837-1-shakeelb@google.com
Link: https://lkml.kernel.org/r/20210305212639.775498-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Tested-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There are two functions to flush the per-cpu data of an lruvec into the
rest of the cgroup tree: when the cgroup is being freed, and when a CPU
disappears during hotplug. The difference is whether all CPUs or just
one is being collected, but the rest of the flushing code is the same.
Merge them into one function and share the common code.
Link: https://lkml.kernel.org/r/20210209163304.77088-8-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Replace the memory controller's custom hierarchical stats code with the
generic rstat infrastructure provided by the cgroup core.
The current implementation does batched upward propagation from the
write side (i.e. as stats change). The per-cpu batches introduce an
error, which is multiplied by the number of subgroups in a tree. In
systems with many CPUs and sizable cgroup trees, the error can be large
enough to confuse users (e.g. 32 batch pages * 32 CPUs * 32 subgroups
results in an error of up to 128M per stat item). This can entirely
swallow allocation bursts inside a workload that the user is expecting
to see reflected in the statistics.
In the past, we've done read-side aggregation, where a memory.stat read
would have to walk the entire subtree and add up per-cpu counts. This
became problematic with lazily-freed cgroups: we could have large
subtrees where most cgroups were entirely idle. Hence the switch to
change-driven upward propagation. Unfortunately, it needed to trade
accuracy for speed due to the write side being so hot.
Rstat combines the best of both worlds: from the write side, it cheaply
maintains a queue of cgroups that have pending changes, so that the read
side can do selective tree aggregation. This way the reported stats
will always be precise and recent as can be, while the aggregation can
skip over potentially large numbers of idle cgroups.
The way rstat works is that it implements a tree for tracking cgroups
with pending local changes, as well as a flush function that walks the
tree upwards. The controller then drives this by 1) telling rstat when
a local cgroup stat changes (e.g. mod_memcg_state) and 2) when a flush
is required to get uptodate hierarchy stats for a given subtree (e.g.
when memory.stat is read). The controller also provides a flush
callback that is called during the rstat flush walk for each cgroup and
aggregates its local per-cpu counters and propagates them upwards.
This adds a second vmstats to struct mem_cgroup (MEMCG_NR_STAT +
NR_VM_EVENT_ITEMS) to track pending subtree deltas during upward
aggregation. It removes 3 words from the per-cpu data. It eliminates
memcg_exact_page_state(), since memcg_page_state() is now exact.
[akpm@linux-foundation.org: merge fix]
[hannes@cmpxchg.org: fix a sleep in atomic section problem]
Link: https://lkml.kernel.org/r/20210315234100.64307-1-hannes@cmpxchg.org
Link: https://lkml.kernel.org/r/20210209163304.77088-7-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There are no users outside of the memory controller itself. The rest
of the kernel cares either about node or lruvec stats.
Link: https://lkml.kernel.org/r/20210209163304.77088-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
No need to encapsulate a simple struct member access.
Link: https://lkml.kernel.org/r/20210209163304.77088-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "mm: memcontrol: switch to rstat", v3.
This series converts memcg stats tracking to the streamlined rstat
infrastructure provided by the cgroup core code. rstat is already used by
the CPU controller and the IO controller. This change is motivated by
recent accuracy problems in memcg's custom stats code, as well as the
benefits of sharing common infra with other controllers.
The current memcg implementation does batched tree aggregation on the
write side: local stat changes are cached in per-cpu counters, which are
then propagated upward in batches when a threshold (32 pages) is exceeded.
This is cheap, but the error introduced by the lazy upward propagation
adds up: 32 pages times CPUs times cgroups in the subtree. We've had
complaints from service owners that the stats do not reliably track and
react to allocation behavior as expected, sometimes swallowing the results
of entire test applications.
The original memcg stat implementation used to do tree aggregation
exclusively on the read side: local stats would only ever be tracked in
per-cpu counters, and a memory.stat read would iterate the entire subtree
and sum those counters up. This didn't keep up with the times:
- Cgroup trees are much bigger now. We switched to lazily-freed
cgroups, where deleted groups would hang around until their remaining
page cache has been reclaimed. This can result in large subtrees that
are expensive to walk, while most of the groups are idle and their
statistics don't change much anymore.
- Automated monitoring increased. With the proliferation of userspace
oom killing, proactive reclaim, and higher-resolution logging of
workload trends in general, top-level stat files are polled at least
once a second in many deployments.
- The lifetime of cgroups got shorter. Where most cgroup setups in the
past would have a few large policy-oriented cgroups for everything
running on the system, newer cgroup deployments tend to create one
group per application - which gets deleted again as the processes
exit. An aggregation scheme that doesn't retain child data inside the
parents loses event history of the subtree.
Rstat addresses all three of those concerns through intelligent,
persistent read-side aggregation. As statistics change at the local
level, rstat tracks - on a per-cpu basis - only those parts of a subtree
that have changes pending and require aggregation. The actual
aggregation occurs on the colder read side - which can now skip over
(potentially large) numbers of recently idle cgroups.
===
The test_kmem cgroup selftest is currently failing due to excessive
cumulative vmstat drift from 100 subgroups:
ok 1 test_kmem_basic
memory.current = 8810496
slab + anon + file + kernel_stack = 17074568
slab = 6101384
anon = 946176
file = 0
kernel_stack = 10027008
not ok 2 test_kmem_memcg_deletion
ok 3 test_kmem_proc_kpagecgroup
ok 4 test_kmem_kernel_stacks
ok 5 test_kmem_dead_cgroups
ok 6 test_percpu_basic
As you can see, memory.stat items far exceed memory.current. The kernel
stack alone is bigger than all of charged memory. That's because the
memory of the test has been uncharged from memory.current, but the
negative vmstat deltas are still sitting in the percpu caches.
The test at this time isn't even counting percpu, pagetables etc. yet,
which would further contribute to the error. The last patch in the series
updates the test to include them - as well as reduces the vmstat
tolerances in general to only expect page_counter batching.
With all patches applied, the (now more stringent) test succeeds:
ok 1 test_kmem_basic
ok 2 test_kmem_memcg_deletion
ok 3 test_kmem_proc_kpagecgroup
ok 4 test_kmem_kernel_stacks
ok 5 test_kmem_dead_cgroups
ok 6 test_percpu_basic
===
A kernel build test confirms that overhead is comparable. Two kernels are
built simultaneously in a nested tree with several idle siblings:
root - kernelbuild - one - two - three - four - build-a (defconfig, make -j16)
`- build-b (defconfig, make -j16)
`- idle-1
`- ...
`- idle-9
During the builds, kernelbuild/memory.stat is read once a second.
A perf diff shows that the changes in cycle distribution is
minimal. Top 10 kernel symbols:
0.09% +0.08% [kernel.kallsyms] [k] __mod_memcg_lruvec_state
0.00% +0.06% [kernel.kallsyms] [k] cgroup_rstat_updated
0.08% -0.05% [kernel.kallsyms] [k] __mod_memcg_state.part.0
0.16% -0.04% [kernel.kallsyms] [k] release_pages
0.00% +0.03% [kernel.kallsyms] [k] __count_memcg_events
0.01% +0.03% [kernel.kallsyms] [k] mem_cgroup_charge_statistics.constprop.0
0.10% -0.02% [kernel.kallsyms] [k] get_mem_cgroup_from_mm
0.05% -0.02% [kernel.kallsyms] [k] mem_cgroup_update_lru_size
0.57% +0.01% [kernel.kallsyms] [k] asm_exc_page_fault
===
The on-demand aggregated stats are now fully accurate:
$ grep -e nr_inactive_file /proc/vmstat | awk '{print($1,$2*4096)}'; \
grep -e inactive_file /sys/fs/cgroup/memory.stat
vanilla: patched:
nr_inactive_file 1574105088 nr_inactive_file 1027801088
inactive_file 1577410560 inactive_file 1027801088
===
This patch (of 8):
The memcg hotunplug callback erroneously flushes counts on the local CPU,
not the counts of the CPU going away; those counts will be lost.
Flush the CPU that is actually going away.
Also simplify the code a bit by using mod_memcg_state() and
count_memcg_events() instead of open-coding the upward flush - this is
comparable to how vmstat.c handles hotunplug flushing.
Link: https://lkml.kernel.org/r/20210209163304.77088-1-hannes@cmpxchg.org
Link: https://lkml.kernel.org/r/20210209163304.77088-2-hannes@cmpxchg.org
Fixes: a983b5ebee572 ("mm: memcontrol: fix excessive complexity in memory.stat reporting")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
In the era of async memcg oom-killer, the commit a0d8b00a3381 ("mm: memcg:
do not declare OOM from __GFP_NOFAIL allocations") added the code to skip
memcg oom-killer for __GFP_NOFAIL allocations. The reason was that the
__GFP_NOFAIL callers will not enter aync oom synchronization path and will
keep the task marked as in memcg oom. At that time the tasks marked in
memcg oom can bypass the memcg limits and the oom synchronization would
have happened later in the later userspace triggered page fault. Thus
letting the task marked as under memcg oom bypass the memcg limit for
arbitrary time.
With the synchronous memcg oom-killer (commit 29ef680ae7c21 ("memcg, oom:
move out_of_memory back to the charge path")) and not letting the task
marked under memcg oom to bypass the memcg limits (commit 1f14c1ac19aa4
("mm: memcg: do not allow task about to OOM kill to bypass the limit")),
we can again allow __GFP_NOFAIL allocations to trigger memcg oom-kill.
This will make memcg oom behavior closer to page allocator oom behavior.
Link: https://lkml.kernel.org/r/20210223204337.2785120-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Replace the implicit checking of root memcg with explicit root memcg
checking i.e. !css->parent with mem_cgroup_is_root().
Link: https://lkml.kernel.org/r/20210223205625.2792891-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Replace /* */ comment with //, fix SPDX comment style.
see: Documentation/process/license-rules.rst
Link: https://lkml.kernel.org/r/1614223348-15516-1-git-send-email-daizhiyuan@phytium.com.cn
Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Since commit 5a52c9df62b4 ("uprobe: use FOLL_SPLIT_PMD instead of
FOLL_SPLIT") and commit ba925fa35057 ("s390/gmap: improve THP splitting")
FOLL_SPLIT has not been used anymore. Remove the dead code.
Link: https://lkml.kernel.org/r/20210330203900.9222-1-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Add an unpin_user_page_range_dirty_lock() API which takes a starting page
and how many consecutive pages we want to unpin and optionally dirty.
To that end, define another iterator for_each_compound_range() that
operates in page ranges as opposed to page array.
For users (like RDMA mr_dereg) where each sg represents a contiguous set
of pages, we're able to more efficiently unpin pages without having to
supply an array of pages much of what happens today with
unpin_user_pages().
Link: https://lkml.kernel.org/r/20210212130843.13865-4-joao.m.martins@oracle.com
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Doug Ledford <dledford@redhat.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>
|
|
Rather than decrementing the head page refcount one by one, we walk the
page array and checking which belong to the same compound_head. Later on
we decrement the calculated amount of references in a single write to the
head page. To that end switch to for_each_compound_head() does most of
the work.
set_page_dirty() needs no adjustment as it's a nop for non-dirty head
pages and it doesn't operate on tail pages.
This considerably improves unpinning of pages with THP and hugetlbfs:
- THP
gup_test -t -m 16384 -r 10 [-L|-a] -S -n 512 -w
PIN_LONGTERM_BENCHMARK (put values): ~87.6k us -> ~23.2k us
- 16G with 1G huge page size
gup_test -f /mnt/huge/file -m 16384 -r 10 [-L|-a] -S -n 512 -w
PIN_LONGTERM_BENCHMARK: (put values): ~87.6k us -> ~27.5k us
Link: https://lkml.kernel.org/r/20210212130843.13865-3-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Doug Ledford <dledford@redhat.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>
|
|
Patch series "mm/gup: page unpining improvements", v4.
This series improves page unpinning, with an eye on improving MR
deregistration for big swaths of memory (which is bound by the page
unpining), particularly:
1) Decrement the head page by @ntails and thus reducing a lot the
number of atomic operations per compound page. This is done by
comparing individual tail pages heads, and counting number of
consecutive tails on which they match heads and based on that update
head page refcount. Should have a visible improvement in all page
(un)pinners which use compound pages
2) Introducing a new API for unpinning page ranges (to avoid the trick
in the previous item and be based on math), and use that in RDMA
ib_mem_release (used for mr deregistration).
Performance improvements: unpin_user_pages() for hugetlbfs and THP
improves ~3x (through gup_test) and RDMA MR dereg improves ~4.5x with the
new API. See patches 2 and 4 for those.
This patch (of 4):
Add a helper that iterates over head pages in a list of pages. It
essentially counts the tails until the next page to process has a
different head that the current. This is going to be used by
unpin_user_pages() family of functions, to batch the head page refcount
updates once for all passed consecutive tail pages.
Link: https://lkml.kernel.org/r/20210212130843.13865-1-joao.m.martins@oracle.com
Link: https://lkml.kernel.org/r/20210212130843.13865-2-joao.m.martins@oracle.com
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
If an unmapped region was found and the flag is MS_ASYNC (without
MS_INVALIDATE) there is nothing to do and the result would be always
-ENOMEM, so return immediately.
Link: https://lkml.kernel.org/r/20201025092901.56399-1-sh1r4s3@mail.si-head.nl
Signed-off-by: Nikita Ermakov <sh1r4s3@mail.si-head.nl>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Commit a6de4b4873e1 ("mm: convert find_get_entry to return the head page")
uses @index instead of @offset, but the comment is stale, update it.
Link: https://lkml.kernel.org/r/1617948260-50724-1-git-send-email-zhangshaokun@hisilicon.com
Signed-off-by: Rui Sun <sunrui26@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.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>
|
|
page_mapping_file() is only used by some architectures, and then it
is usually only used in one place. Make it a static inline function
so other architectures don't have to carry this dead code.
Link: https://lkml.kernel.org/r/20210317123011.350118-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Page writeback doesn't hold a page reference, which allows truncate to
free a page the second PageWriteback is cleared. This used to require
special attention in test_clear_page_writeback(), where we had to be
careful not to rely on the unstable page->memcg binding and look up all
the necessary information before clearing the writeback flag.
Since commit 073861ed77b6 ("mm: fix VM_BUG_ON(PageTail) and
BUG_ON(PageWriteback)") test_clear_page_writeback() is called with an
explicit reference on the page, and this dance is no longer needed.
Use unlock_page_memcg() and dec_lruvec_page_state() directly.
This removes the last user of the lock_page_memcg() return value, change
it to void. Touch up the comments in there as well. This also removes
the last extern user of __unlock_page_memcg(), make it static. Further,
it removes the last user of dec_lruvec_state(), delete it, along with a
few other unused helpers.
Link: https://lkml.kernel.org/r/YCQbYAWg4nvBFL6h@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
If the I/O completed successfully, the page will remain Uptodate, even
if it is subsequently truncated. If the I/O completed with an error,
this check would cause us to retry the I/O if the page were truncated
before we woke up. There is no need to retry the I/O; the I/O to fill
the page failed, so we can legitimately just return -EIO.
This code was originally added by commit 56f0d5fe6851 ("[PATCH]
readpage-vs-invalidate fix") in 2005 (this commit ID is from the
linux-fullhistory tree; it is also commit ba1f08f14b52 in tglx-history).
At the time, truncate_complete_page() called ClearPageUptodate(), and so
this was fixing a real bug. In 2008, commit 84209e02de48 ("mm: dont clear
PG_uptodate on truncate/invalidate") removed the call to
ClearPageUptodate, and this check has been unnecessary ever since.
It doesn't do any real harm, but there's no need to keep it.
Link: https://lkml.kernel.org/r/20210303222547.1056428-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
After splitting generic_file_buffered_read() into smaller parts, it turns
out we can reuse one of the parts in filemap_fault(). This fixes an
oversight -- waiting for the I/O to complete is now interruptible by a
fatal signal. And it saves us a few bytes of text in an unlikely path.
$ ./scripts/bloat-o-meter before.o after.o
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-207 (-207)
Function old new delta
filemap_fault 2187 1980 -207
Total: Before=37491, After=37284, chg -0.55%
Link: https://lkml.kernel.org/r/20210226140011.2883498-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
For the generic page cache read helper, use the better variant of checking
for the need to call filemap_write_and_wait_range() when doing O_DIRECT
reads. This avoids falling back to the slow path for IOCB_NOWAIT, if
there are no pages to wait for (or write out).
Link: https://lkml.kernel.org/r/20210224164455.1096727-3-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "Improve IOCB_NOWAIT O_DIRECT reads", v3.
An internal workload complained because it was using too much CPU, and
when I took a look, we had a lot of io_uring workers going to town.
For an async buffered read like workload, I am normally expecting _zero_
offloads to a worker thread, but this one had tons of them. I'd drop
caches and things would look good again, but then a minute later we'd
regress back to using workers. Turns out that every minute something
was reading parts of the device, which would add page cache for that
inode. I put patches like these in for our kernel, and the problem was
solved.
Don't -EAGAIN IOCB_NOWAIT dio reads just because we have page cache
entries for the given range. This causes unnecessary work from the
callers side, when the IO could have been issued totally fine without
blocking on writeback when there is none.
This patch (of 3):
For O_DIRECT reads/writes, we check if we need to issue a call to
filemap_write_and_wait_range() to issue and/or wait for writeback for any
page in the given range. The existing mechanism just checks for a page in
the range, which is suboptimal for IOCB_NOWAIT as we'll fallback to the
slow path (and needing retry) if there's just a clean page cache page in
the range.
Provide filemap_range_needs_writeback() which tries a little harder to
check if we actually need to issue and/or wait for writeback in the range.
Link: https://lkml.kernel.org/r/20210224164455.1096727-1-axboe@kernel.dk
Link: https://lkml.kernel.org/r/20210224164455.1096727-2-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When page_poison detects page corruption it's useful to see who freed a
page recently to have a guess where write-after-free corruption happens.
After this change corruption report has extra page data.
Example report from real corruption (includes only page_pwner part):
pagealloc: memory corruption
e00000014cd61d10: 11 00 00 00 00 00 00 00 30 1d d2 ff ff 0f 00 60 ........0......`
e00000014cd61d20: b0 1d d2 ff ff 0f 00 60 90 fe 1c 00 08 00 00 20 .......`.......
...
CPU: 1 PID: 220402 Comm: cc1plus Not tainted 5.12.0-rc5-00107-g9720c6f59ecf #245
Hardware name: hp server rx3600, BIOS 04.03 04/08/2008
...
Call Trace:
[<a000000100015210>] show_stack+0x90/0xc0
[<a000000101163390>] dump_stack+0x150/0x1c0
[<a0000001003f1e90>] __kernel_unpoison_pages+0x410/0x440
[<a0000001003c2460>] get_page_from_freelist+0x1460/0x2ca0
[<a0000001003c6be0>] __alloc_pages_nodemask+0x3c0/0x660
[<a0000001003ed690>] alloc_pages_vma+0xb0/0x500
[<a00000010037deb0>] __handle_mm_fault+0x1230/0x1fe0
[<a00000010037ef70>] handle_mm_fault+0x310/0x4e0
[<a00000010005dc70>] ia64_do_page_fault+0x1f0/0xb80
[<a00000010000ca00>] ia64_leave_kernel+0x0/0x270
page_owner tracks the page as freed
page allocated via order 0, migratetype Movable,
gfp_mask 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 37, ts 8173444098740
__reset_page_owner+0x40/0x200
free_pcp_prepare+0x4d0/0x600
free_unref_page+0x20/0x1c0
__put_page+0x110/0x1a0
migrate_pages+0x16d0/0x1dc0
compact_zone+0xfc0/0x1aa0
proactive_compact_node+0xd0/0x1e0
kcompactd+0x550/0x600
kthread+0x2c0/0x2e0
call_payload+0x50/0x80
Here we can see that page was freed by page migration but something
managed to write to it afterwards.
[slyfox@gentoo.org: s/dump_page_owner/dump_page/, per Vlastimil]
Link: https://lkml.kernel.org/r/20210407230800.1086854-1-slyfox@gentoo.org
Link: https://lkml.kernel.org/r/20210404141735.2152984-1-slyfox@gentoo.org
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Before the change page_owner recursion was detected via fetching
backtrace and inspecting it for current instruction pointer.
It has a few problems:
- it is slightly slow as it requires extra backtrace and a linear stack
scan of the result
- it is too late to check if backtrace fetching required memory
allocation itself (ia64's unwinder requires it).
To simplify recursion tracking let's use page_owner recursion flag in
'struct task_struct'.
The change make page_owner=on work on ia64 by avoiding infinite
recursion in:
kmalloc()
-> __set_page_owner()
-> save_stack()
-> unwind() [ia64-specific]
-> build_script()
-> kmalloc()
-> __set_page_owner() [we short-circuit here]
-> save_stack()
-> unwind() [recursion]
Link: https://lkml.kernel.org/r/20210402115342.1463781-1-slyfox@gentoo.org
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
I tried to use page_owner=1 for a while noticed too late it had no effect
as opposed to similar init_on_alloc=1 (these work).
Let's make them consistent.
The change decreses binary size slightly:
text data bss dec hex filename
12408 321 17 12746 31ca mm/page_owner.o.before
12320 321 17 12658 3172 mm/page_owner.o.after
Link: https://lkml.kernel.org/r/20210401210909.3532086-1-slyfox@gentoo.org
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Very minor optimization.
Link: https://lkml.kernel.org/r/20210401212445.3534721-1-slyfox@gentoo.org
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Since commit 5556cfe8d994 ("mm, page_owner: fix off-by-one error in
__set_page_owner_handle()") introduced, the parameter 'page' will not
used, hence it need to be removed.
Link: https://lkml.kernel.org/r/1616602022-43545-1-git-send-email-zhongjiang-ali@linux.alibaba.com
Signed-off-by: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Collect the time when each allocation is freed, to help with memory
analysis with kdump/ramdump. Add the timestamp also in the page_owner
debugfs file and print it in dump_page().
Having another timestamp when we free the page helps for debugging page
migration issues. For example both alloc and free timestamps being the
same can gave hints that there is an issue with migrating memory, as
opposed to a page just being dropped during migration.
Link: https://lkml.kernel.org/r/20210203175905.12267-1-georgi.djakov@linaro.org
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
s/interruptable/interruptible/
Link: https://lkml.kernel.org/r/20210319214140.23304-1-unixbhaskar@gmail.com
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
s/operatios/operations/
s/Mininum/Minimum/
s/mininum/minimum/ ......two different places.
Link: https://lkml.kernel.org/r/20210325044940.14516-1-unixbhaskar@gmail.com
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
debug flags
Commit ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()")
introduced a static key to optimize the case where no debugging is
enabled for any cache. The static key is enabled when slub_debug boot
parameter is passed, or CONFIG_SLUB_DEBUG_ON enabled.
However, some caches might be created with one or more debugging flags
explicitly passed to kmem_cache_create(), and the commit missed this.
Thus the debugging functionality would not be actually performed for
these caches unless the static key gets enabled by boot param or config.
This patch fixes it by checking for debugging flags passed to
kmem_cache_create() and enabling the static key accordingly.
Note such explicit debugging flags should not be used outside of
debugging and testing as they will now enable the static key globally.
btrfs_init_cachep() creates a cache with SLAB_RED_ZONE but that's a
mistake that's being corrected [1]. rcu_torture_stats() creates a cache
with SLAB_STORE_USER, but that is a testing module so it's OK and will
start working as intended after this patch.
Also note that in case of backports to kernels before v5.12 that don't
have 59450bbc12be ("mm, slab, slub: stop taking cpu hotplug lock"),
static_branch_enable_cpuslocked() should be used.
[1] https://lore.kernel.org/linux-btrfs/20210315141824.26099-1-dsterba@suse.com/
Link: https://lkml.kernel.org/r/20210315153415.24404-1-vbabka@suse.cz
Fixes: ca0cab65ea2b ("mm, slub: introduce static key for slub_debug()")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Oliver Glitta <glittao@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
!IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT) builds
This is a minor addition to the allocator setup options to provide a
simple way to on demand enable back cache merging for builds that by
default run with CONFIG_SLAB_MERGE_DEFAULT not set.
Link: https://lkml.kernel.org/r/20210319194506.200159-1-aquini@redhat.com
Signed-off-by: Rafael Aquini <aquini@redhat.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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify updates from Jan Kara:
- support for limited fanotify functionality for unpriviledged users
- faster merging of fanotify events
- a few smaller fsnotify improvements
* tag 'fsnotify_for_v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
shmem: allow reporting fanotify events with file handles on tmpfs
fs: introduce a wrapper uuid_to_fsid()
fanotify_user: use upper_32_bits() to verify mask
fanotify: support limited functionality for unprivileged users
fanotify: configurable limits via sysfs
fanotify: limit number of event merge attempts
fsnotify: use hash table for faster events merge
fanotify: mix event info and pid into merge key hash
fanotify: reduce event objectid to 29-bit hash
fsnotify: allow fsnotify_{peek,remove}_first_event with empty queue
|
|
Pull block updates from Jens Axboe:
"Pretty quiet round this time, which is nice. In detail:
- Series revamping bounce buffer support (Christoph)
- Dead code removal (Christoph, Bart)
- Partition iteration revamp, now using xarray (Christoph)
- Passthrough request scheduler improvements (Lin)
- Series of BFQ improvements (Paolo)
- Fix ioprio task iteration (Peter)
- Various little tweaks and fixes (Tejun, Saravanan, Bhaskar, Max,
Nikolay)"
* tag 'for-5.13/block-2021-04-27' of git://git.kernel.dk/linux-block: (41 commits)
blk-iocost: don't ignore vrate_min on QD contention
blk-mq: Fix spurious debugfs directory creation during initialization
bfq/mq-deadline: remove redundant check for passthrough request
blk-mq: bypass IO scheduler's limit_depth for passthrough request
block: Remove an obsolete comment from sg_io()
block: move bio_list_copy_data to pktcdvd
block: remove zero_fill_bio_iter
block: add queue_to_disk() to get gendisk from request_queue
block: remove an incorrect check from blk_rq_append_bio
block: initialize ret in bdev_disk_changed
block: Fix sys_ioprio_set(.which=IOPRIO_WHO_PGRP) task iteration
block: remove disk_part_iter
block: simplify diskstats_show
block: simplify show_partition
block: simplify printk_all_partitions
block: simplify partition_overlaps
block: simplify partition removal
block: take bd_mutex around delete_partitions in del_gendisk
block: refactor blk_drop_partitions
block: move more syncing and invalidation to delete_partition
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
- Support for "N" as alias for last bit in bitmap parsing library (eg
using syntax like "nohz_full=2-N")
- kvfree_rcu updates
- mm_dump_obj() updates. (One of these is to mm, but was suggested by
Andrew Morton.)
- RCU callback offloading update
- Polling RCU grace-period interfaces
- Realtime-related RCU updates
- Tasks-RCU updates
- Torture-test updates
- Torture-test scripting updates
- Miscellaneous fixes
* tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits)
rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu()
rcu: Provide polling interfaces for Tiny RCU grace periods
torture: Fix kvm.sh --datestamp regex check
torture: Consolidate qemu-cmd duration editing into kvm-transform.sh
torture: Print proper vmlinux path for kvm-again.sh runs
torture: Make TORTURE_TRUST_MAKE available in kvm-again.sh environment
torture: Make kvm-transform.sh update jitter commands
torture: Add --duration argument to kvm-again.sh
torture: Add kvm-again.sh to rerun a previous torture-test
torture: Create a "batches" file for build reuse
torture: De-capitalize TORTURE_SUITE
torture: Make upper-case-only no-dot no-slash scenario names official
torture: Rename SRCU-t and SRCU-u to avoid lowercase characters
torture: Remove no-mpstat error message
torture: Record kvm-test-1-run.sh and kvm-test-1-run-qemu.sh PIDs
torture: Record jitter start/stop commands
torture: Extract kvm-test-1-run-qemu.sh from kvm-test-1-run.sh
torture: Record TORTURE_KCONFIG_GDB_ARG in qemu-cmd
torture: Abstract jitter.sh start/stop into scripts
rcu: Provide polling interfaces for Tree RCU grace periods
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek:
- Stop synchronizing kernel log buffer readers by logbuf_lock. As a
result, the access to the buffer is fully lockless now.
Note that printk() itself still uses locks because it tries to flush
the messages to the console immediately. Also the per-CPU temporary
buffers are still there because they prevent infinite recursion and
serialize backtraces from NMI. All this is going to change in the
future.
- kmsg_dump API rework and cleanup as a side effect of the logbuf_lock
removal.
- Make bstr_printf() aware that %pf and %pF formats could deference the
given pointer.
- Show also page flags by %pGp format.
- Clarify the documentation for plain pointer printing.
- Do not show no_hash_pointers warning multiple times.
- Update Senozhatsky email address.
- Some clean up.
* tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (24 commits)
lib/vsprintf.c: remove leftover 'f' and 'F' cases from bstr_printf()
printk: clarify the documentation for plain pointer printing
kernel/printk.c: Fixed mundane typos
printk: rename vprintk_func to vprintk
vsprintf: dump full information of page flags in pGp
mm, slub: don't combine pr_err with INFO
mm, slub: use pGp to print page flags
MAINTAINERS: update Senozhatsky email address
lib/vsprintf: do not show no_hash_pointers message multiple times
printk: console: remove unnecessary safe buffer usage
printk: kmsg_dump: remove _nolock() variants
printk: remove logbuf_lock
printk: introduce a kmsg_dump iterator
printk: kmsg_dumper: remove @active field
printk: add syslog_lock
printk: use atomic64_t for devkmsg_user.seq
printk: use seqcount_latch for clear_seq
printk: introduce CONSOLE_LOG_MAX
printk: consolidate kmsg_dump_get_buffer/syslog_print_all code
printk: refactor kmsg_dump_get_buffer()
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull network filesystem helper library updates from David Howells:
"Here's a set of patches for 5.13 to begin the process of overhauling
the local caching API for network filesystems. This set consists of
two parts:
(1) Add a helper library to handle the new VM readahead interface.
This is intended to be used unconditionally by the filesystem
(whether or not caching is enabled) and provides a common
framework for doing caching, transparent huge pages and, in the
future, possibly fscrypt and read bandwidth maximisation. It also
allows the netfs and the cache to align, expand and slice up a
read request from the VM in various ways; the netfs need only
provide a function to read a stretch of data to the pagecache and
the helper takes care of the rest.
(2) Add an alternative fscache/cachfiles I/O API that uses the kiocb
facility to do async DIO to transfer data to/from the netfs's
pages, rather than using readpage with wait queue snooping on one
side and vfs_write() on the other. It also uses less memory, since
it doesn't do buffered I/O on the backing file.
Note that this uses SEEK_HOLE/SEEK_DATA to locate the data
available to be read from the cache. Whilst this is an improvement
from the bmap interface, it still has a problem with regard to a
modern extent-based filesystem inserting or removing bridging
blocks of zeros. Fixing that requires a much greater overhaul.
This is a step towards overhauling the fscache API. The change is
opt-in on the part of the network filesystem. A netfs should not try
to mix the old and the new API because of conflicting ways of handling
pages and the PG_fscache page flag and because it would be mixing DIO
with buffered I/O. Further, the helper library can't be used with the
old API.
This does not change any of the fscache cookie handling APIs or the
way invalidation is done at this time.
In the near term, I intend to deprecate and remove the old I/O API
(fscache_allocate_page{,s}(), fscache_read_or_alloc_page{,s}(),
fscache_write_page() and fscache_uncache_page()) and eventually
replace most of fscache/cachefiles with something simpler and easier
to follow.
This patchset contains the following parts:
- Some helper patches, including provision of an ITER_XARRAY iov
iterator and a function to do readahead expansion.
- Patches to add the netfs helper library.
- A patch to add the fscache/cachefiles kiocb API.
- A pair of patches to fix some review issues in the ITER_XARRAY and
read helpers as spotted by Al and Willy.
Jeff Layton has patches to add support in Ceph for this that he
intends for this merge window. I have a set of patches to support AFS
that I will post a separate pull request for.
With this, AFS without a cache passes all expected xfstests; with a
cache, there's an extra failure, but that's also there before these
patches. Fixing that probably requires a greater overhaul. Ceph also
passes the expected tests.
I also have patches in a separate branch to tidy up the handling of
PG_fscache/PG_private_2 and their contribution to page refcounting in
the core kernel here, but I haven't included them in this set and will
route them separately"
Link: https://lore.kernel.org/lkml/3779937.1619478404@warthog.procyon.org.uk/
* tag 'netfs-lib-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
netfs: Miscellaneous fixes
iov_iter: Four fixes for ITER_XARRAY
fscache, cachefiles: Add alternate API to use kiocb for read/write to cache
netfs: Add a tracepoint to log failures that would be otherwise unseen
netfs: Define an interface to talk to a cache
netfs: Add write_begin helper
netfs: Gather stats
netfs: Add tracepoints
netfs: Provide readahead and readpage netfs helpers
netfs, mm: Add set/end/wait_on_page_fscache() aliases
netfs, mm: Move PG_fscache helper funcs to linux/netfs.h
netfs: Documentation for helper library
netfs: Make a netfs helper module
mm: Implement readahead_control pageset expansion
mm/readahead: Handle ractl nr_pages being modified
fs: Document file_ra_state
mm/filemap: Pass the file_ra_state in the ractl
mm: Add set/end/wait functions for PG_private_2
iov_iter: Add ITER_XARRAY
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- MTE asynchronous support for KASan. Previously only synchronous
(slower) mode was supported. Asynchronous is faster but does not
allow precise identification of the illegal access.
- Run kernel mode SIMD with softirqs disabled. This allows using NEON
in softirq context for crypto performance improvements. The
conditional yield support is modified to take softirqs into account
and reduce the latency.
- Preparatory patches for Apple M1: handle CPUs that only have the VHE
mode available (host kernel running at EL2), add FIQ support.
- arm64 perf updates: support for HiSilicon PA and SLLC PMU drivers,
new functions for the HiSilicon HHA and L3C PMU, cleanups.
- Re-introduce support for execute-only user permissions but only when
the EPAN (Enhanced Privileged Access Never) architecture feature is
available.
- Disable fine-grained traps at boot and improve the documented boot
requirements.
- Support CONFIG_KASAN_VMALLOC on arm64 (only with KASAN_GENERIC).
- Add hierarchical eXecute Never permissions for all page tables.
- Add arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) allowing user programs
to control which PAC keys are enabled in a particular task.
- arm64 kselftests for BTI and some improvements to the MTE tests.
- Minor improvements to the compat vdso and sigpage.
- Miscellaneous cleanups.
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (86 commits)
arm64/sve: Add compile time checks for SVE hooks in generic functions
arm64/kernel/probes: Use BUG_ON instead of if condition followed by BUG.
arm64: pac: Optimize kernel entry/exit key installation code paths
arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS)
arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere
arm64/sve: Remove redundant system_supports_sve() tests
arm64: fpsimd: run kernel mode NEON with softirqs disabled
arm64: assembler: introduce wxN aliases for wN registers
arm64: assembler: remove conditional NEON yield macros
kasan, arm64: tests supports for HW_TAGS async mode
arm64: mte: Report async tag faults before suspend
arm64: mte: Enable async tag check fault
arm64: mte: Conditionally compile mte_enable_kernel_*()
arm64: mte: Enable TCO in functions that can read beyond buffer limits
kasan: Add report for async mode
arm64: mte: Drop arch_enable_tagging()
kasan: Add KASAN mode kernel parameter
arm64: mte: Add asynchronous mode support
arm64: Get rid of CONFIG_ARM64_VHE
arm64: Cope with CPUs stuck in VHE mode
...
|
Brian Geffon
Huang Ying
Christoph Hellwig
Zhiyuan Dai
Wang Qing
Johannes Weiner
Muchun Song
Shakeel Butt
Yang Shi
Joao Martins
Nikita Ermakov
Rui Sun
Matthew Wilcox (Oracle)
Jens Axboe
Sergei Trofimovich
zhongjiang-ali
Georgi Djakov
Bhaskar Chowdhury
Vlastimil Babka
Rafael Aquini
Linus Torvalds
