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745 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
David Hildenbrand
|
c4dffb0bc2 |
mm/migrate: page_add_file_rmap() -> folio_add_file_rmap_pte()
Let's convert remove_migration_pte(). Link: https://lkml.kernel.org/r/20231220224504.646757-11-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
|
44887f3994 |
mm/rmap: introduce and use hugetlb_add_file_rmap()
hugetlb rmap handling differs quite a lot from "ordinary" rmap code. For example, hugetlb currently only supports entire mappings, and treats any mapping as mapped using a single "logical PTE". Let's move it out of the way so we can overhaul our "ordinary" rmap. implementation/interface. Right now we're using page_dup_file_rmap() in some cases where "ordinary" rmap code would have used page_add_file_rmap(). So let's introduce and use hugetlb_add_file_rmap() instead. We won't be adding a "hugetlb_dup_file_rmap()" functon for the fork() case, as it would be doing the same: "dup" is just an optimization for "add". What remains is a single page_dup_file_rmap() call in fork() code. Add sanity checks that we end up with the right folios in the right functions. Link: https://lkml.kernel.org/r/20231220224504.646757-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
David Hildenbrand
|
9d5fafd5d8 |
mm/rmap: rename hugepage_add* to hugetlb_add*
Patch series "mm/rmap: interface overhaul", v2. This series overhauls the rmap interface, to get rid of the "bool compound" / RMAP_COMPOUND parameter with the goal of making the interface less error prone, more future proof, and more natural to extend to "batching". Also, this converts the interface to always consume folio+subpage, which speeds up operations on large folios. Further, this series adds PTE-batching variants for 4 rmap functions, whereby only folio_add_anon_rmap_ptes() is used for batching in this series when PTE-remapping a PMD-mapped THP. folio_remove_rmap_ptes(), folio_try_dup_anon_rmap_ptes() and folio_dup_file_rmap_ptes() will soon come in handy[1,2]. This series performs a lot of folio conversion along the way. Most of the added LOC in the diff are only due to documentation. As we're moving to a pte/pmd interface where we clearly express the mapping granularity we are dealing with, we first get the remainder of hugetlb out of the way, as it is special and expected to remain special: it treats everything as a "single logical PTE" and only currently allows entire mappings. Even if we'd ever support partial mappings, I strongly assume the interface and implementation will still differ heavily: hopefull we can avoid working on subpages/subpage mapcounts completely and only add a "count" parameter for them to enable batching. New (extended) hugetlb interface that operates on entire folio: * hugetlb_add_new_anon_rmap() -> Already existed * hugetlb_add_anon_rmap() -> Already existed * hugetlb_try_dup_anon_rmap() * hugetlb_try_share_anon_rmap() * hugetlb_add_file_rmap() * hugetlb_remove_rmap() New "ordinary" interface for small folios / THP:: * folio_add_new_anon_rmap() -> Already existed * folio_add_anon_rmap_[pte|ptes|pmd]() * folio_try_dup_anon_rmap_[pte|ptes|pmd]() * folio_try_share_anon_rmap_[pte|pmd]() * folio_add_file_rmap_[pte|ptes|pmd]() * folio_dup_file_rmap_[pte|ptes|pmd]() * folio_remove_rmap_[pte|ptes|pmd]() folio_add_new_anon_rmap() will always map at the largest granularity possible (currently, a single PMD to cover a PMD-sized THP). Could be extended if ever required. In the future, we might want "_pud" variants and eventually "_pmds" variants for batching. I ran some simple microbenchmarks on an Intel(R) Xeon(R) Silver 4210R: measuring munmap(), fork(), cow, MADV_DONTNEED on each PTE ... and PTE remapping PMD-mapped THPs on 1 GiB of memory. For small folios, there is barely a change (< 1% improvement for me). For PTE-mapped THP: * PTE-remapping a PMD-mapped THP is more than 10% faster. * fork() is more than 4% faster. * MADV_DONTNEED is 2% faster * COW when writing only a single byte on a COW-shared PTE is 1% faster * munmap() barely changes (< 1%). [1] https://lkml.kernel.org/r/20230810103332.3062143-1-ryan.roberts@arm.com [2] https://lkml.kernel.org/r/20231204105440.61448-1-ryan.roberts@arm.com This patch (of 40): Let's just call it "hugetlb_". Yes, it's all already inconsistent and confusing because we have a lot of "hugepage_" functions for legacy reasons. But "hugetlb" cannot possibly be confused with transparent huge pages, and it matches "hugetlb.c" and "folio_test_hugetlb()". So let's minimize confusion in rmap code. Link: https://lkml.kernel.org/r/20231220224504.646757-1-david@redhat.com Link: https://lkml.kernel.org/r/20231220224504.646757-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Baolin Wang
|
d1adb25df7 |
mm: migrate: fix getting incorrect page mapping during page migration
When running stress-ng testing, we found below kernel crash after a few hours:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
pc : dentry_name+0xd8/0x224
lr : pointer+0x22c/0x370
sp : ffff800025f134c0
......
Call trace:
dentry_name+0xd8/0x224
pointer+0x22c/0x370
vsnprintf+0x1ec/0x730
vscnprintf+0x2c/0x60
vprintk_store+0x70/0x234
vprintk_emit+0xe0/0x24c
vprintk_default+0x3c/0x44
vprintk_func+0x84/0x2d0
printk+0x64/0x88
__dump_page+0x52c/0x530
dump_page+0x14/0x20
set_migratetype_isolate+0x110/0x224
start_isolate_page_range+0xc4/0x20c
offline_pages+0x124/0x474
memory_block_offline+0x44/0xf4
memory_subsys_offline+0x3c/0x70
device_offline+0xf0/0x120
......
After analyzing the vmcore, I found this issue is caused by page migration.
The scenario is that, one thread is doing page migration, and we will use the
target page's ->mapping field to save 'anon_vma' pointer between page unmap and
page move, and now the target page is locked and refcount is 1.
Currently, there is another stress-ng thread performing memory hotplug,
attempting to offline the target page that is being migrated. It discovers that
the refcount of this target page is 1, preventing the offline operation, thus
proceeding to dump the page. However, page_mapping() of the target page may
return an incorrect file mapping to crash the system in dump_mapping(), since
the target page->mapping only saves 'anon_vma' pointer without setting
PAGE_MAPPING_ANON flag.
There are seveval ways to fix this issue:
(1) Setting the PAGE_MAPPING_ANON flag for target page's ->mapping when saving
'anon_vma', but this can confuse PageAnon() for PFN walkers, since the target
page has not built mappings yet.
(2) Getting the page lock to call page_mapping() in __dump_page() to avoid crashing
the system, however, there are still some PFN walkers that call page_mapping()
without holding the page lock, such as compaction.
(3) Using target page->private field to save the 'anon_vma' pointer and 2 bits
page state, just as page->mapping records an anonymous page, which can remove
the page_mapping() impact for PFN walkers and also seems a simple way.
So I choose option 3 to fix this issue, and this can also fix other potential
issues for PFN walkers, such as compaction.
Link: https://lkml.kernel.org/r/e60b17a88afc38cb32f84c3e30837ec70b343d2b.1702641709.git.baolin.wang@linux.alibaba.com
Fixes:
|
||
Charan Teja Kalla
|
fc346d0a70 |
mm: migrate high-order folios in swap cache correctly
Large folios occupy N consecutive entries in the swap cache instead of
using multi-index entries like the page cache. However, if a large folio
is re-added to the LRU list, it can be migrated. The migration code was
not aware of the difference between the swap cache and the page cache and
assumed that a single xas_store() would be sufficient.
This leaves potentially many stale pointers to the now-migrated folio in
the swap cache, which can lead to almost arbitrary data corruption in the
future. This can also manifest as infinite loops with the RCU read lock
held.
[willy@infradead.org: modifications to the changelog & tweaked the fix]
Fixes:
|
||
Matthew Wilcox (Oracle)
|
600f111ef5 |
fs: Rename mapping private members
It is hard to find where mapping->private_lock, mapping->private_list and mapping->private_data are used, due to private_XXX being a relatively common name for variables and structure members in the kernel. To fit with other members of struct address_space, rename them all to have an i_ prefix. Tested with an allmodconfig build. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Link: https://lore.kernel.org/r/20231117215823.2821906-1-willy@infradead.org Acked-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Christian Brauner <brauner@kernel.org> |
||
Paolo Bonzini
|
6c370dc653 |
Merge branch 'kvm-guestmemfd' into HEAD
Introduce several new KVM uAPIs to ultimately create a guest-first memory
subsystem within KVM, a.k.a. guest_memfd. Guest-first memory allows KVM
to provide features, enhancements, and optimizations that are kludgly
or outright impossible to implement in a generic memory subsystem.
The core KVM ioctl() for guest_memfd is KVM_CREATE_GUEST_MEMFD, which
similar to the generic memfd_create(), creates an anonymous file and
returns a file descriptor that refers to it. Again like "regular"
memfd files, guest_memfd files live in RAM, have volatile storage,
and are automatically released when the last reference is dropped.
The key differences between memfd files (and every other memory subystem)
is that guest_memfd files are bound to their owning virtual machine,
cannot be mapped, read, or written by userspace, and cannot be resized.
guest_memfd files do however support PUNCH_HOLE, which can be used to
convert a guest memory area between the shared and guest-private states.
A second KVM ioctl(), KVM_SET_MEMORY_ATTRIBUTES, allows userspace to
specify attributes for a given page of guest memory. In the long term,
it will likely be extended to allow userspace to specify per-gfn RWX
protections, including allowing memory to be writable in the guest
without it also being writable in host userspace.
The immediate and driving use case for guest_memfd are Confidential
(CoCo) VMs, specifically AMD's SEV-SNP, Intel's TDX, and KVM's own pKVM.
For such use cases, being able to map memory into KVM guests without
requiring said memory to be mapped into the host is a hard requirement.
While SEV+ and TDX prevent untrusted software from reading guest private
data by encrypting guest memory, pKVM provides confidentiality and
integrity *without* relying on memory encryption. In addition, with
SEV-SNP and especially TDX, accessing guest private memory can be fatal
to the host, i.e. KVM must be prevent host userspace from accessing
guest memory irrespective of hardware behavior.
Long term, guest_memfd may be useful for use cases beyond CoCo VMs,
for example hardening userspace against unintentional accesses to guest
memory. As mentioned earlier, KVM's ABI uses userspace VMA protections to
define the allow guest protection (with an exception granted to mapping
guest memory executable), and similarly KVM currently requires the guest
mapping size to be a strict subset of the host userspace mapping size.
Decoupling the mappings sizes would allow userspace to precisely map
only what is needed and with the required permissions, without impacting
guest performance.
A guest-first memory subsystem also provides clearer line of sight to
things like a dedicated memory pool (for slice-of-hardware VMs) and
elimination of "struct page" (for offload setups where userspace _never_
needs to DMA from or into guest memory).
guest_memfd is the result of 3+ years of development and exploration;
taking on memory management responsibilities in KVM was not the first,
second, or even third choice for supporting CoCo VMs. But after many
failed attempts to avoid KVM-specific backing memory, and looking at
where things ended up, it is quite clear that of all approaches tried,
guest_memfd is the simplest, most robust, and most extensible, and the
right thing to do for KVM and the kernel at-large.
The "development cycle" for this version is going to be very short;
ideally, next week I will merge it as is in kvm/next, taking this through
the KVM tree for 6.8 immediately after the end of the merge window.
The series is still based on 6.6 (plus KVM changes for 6.7) so it
will require a small fixup for changes to get_file_rcu() introduced in
6.7 by commit
|
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Sean Christopherson
|
0003e2a414 |
mm: Add AS_UNMOVABLE to mark mapping as completely unmovable
Add an "unmovable" flag for mappings that cannot be migrated under any circumstance. KVM will use the flag for its upcoming GUEST_MEMFD support, which will not support compaction/migration, at least not in the foreseeable future. Test AS_UNMOVABLE under folio lock as already done for the async compaction/dirty folio case, as the mapping can be removed by truncation while compaction is running. To avoid having to lock every folio with a mapping, assume/require that unmovable mappings are also unevictable, and have mapping_set_unmovable() also set AS_UNEVICTABLE. Cc: Matthew Wilcox <willy@infradead.org> Co-developed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20231027182217.3615211-15-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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|
Baolin Wang
|
eebb3dabbb |
mm: migrate: record the mlocked page status to remove unnecessary lru drain
When doing compaction, I found the lru_add_drain() is an obvious hotspot
when migrating pages. The distribution of this hotspot is as follows:
- 18.75% compact_zone
- 17.39% migrate_pages
- 13.79% migrate_pages_batch
- 11.66% migrate_folio_move
- 7.02% lru_add_drain
+ 7.02% lru_add_drain_cpu
+ 3.00% move_to_new_folio
1.23% rmap_walk
+ 1.92% migrate_folio_unmap
+ 3.20% migrate_pages_sync
+ 0.90% isolate_migratepages
The lru_add_drain() was added by commit
|
||
Zi Yan
|
49cac03a8f |
mm/migrate: add nr_split to trace_mm_migrate_pages stats.
Add nr_split to trace_mm_migrate_pages for large folio (including THP) split events. [akpm@linux-foundation.org: cleanup per Huang, Ying] Link: https://lkml.kernel.org/r/20231017163129.2025214-2-zi.yan@sent.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Zi Yan
|
a259945efe |
mm/migrate: correct nr_failed in migrate_pages_sync()
nr_failed was missing the large folio splits from migrate_pages_batch()
and can cause a mismatch between migrate_pages() return value and the
number of not migrated pages, i.e., when the return value of
migrate_pages() is 0, there are still pages left in the from page list.
It will happen when a non-PMD THP large folio fails to migrate due to
-ENOMEM and is split successfully but not all the split pages are not
migrated, migrate_pages_batch() would return non-zero, but
astats.nr_thp_split = 0. nr_failed would be 0 and returned to the caller
of migrate_pages(), but the not migrated pages are left in the from page
list without being added back to LRU lists.
Fix it by adding a new nr_split counter for large folio splits and adding
it to nr_failed in migrate_page_sync() after migrate_pages_batch() is
done.
Link: https://lkml.kernel.org/r/20231017163129.2025214-1-zi.yan@sent.com
Fixes:
|
||
Kefeng Wang
|
4e694fe4d2 |
mm: migrate: use folio_xchg_last_cpupid() in folio_migrate_flags()
Convert to use folio_xchg_last_cpupid() in folio_migrate_flags(), also directly use folio_nid() instead of page_to_nid(&folio->page). Link: https://lkml.kernel.org/r/20231018140806.2783514-15-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Nhat Pham
|
8cba9576df |
hugetlb: memcg: account hugetlb-backed memory in memory controller
Currently, hugetlb memory usage is not acounted for in the memory
controller, which could lead to memory overprotection for cgroups with
hugetlb-backed memory. This has been observed in our production system.
For instance, here is one of our usecases: suppose there are two 32G
containers. The machine is booted with hugetlb_cma=6G, and each container
may or may not use up to 3 gigantic page, depending on the workload within
it. The rest is anon, cache, slab, etc. We can set the hugetlb cgroup
limit of each cgroup to 3G to enforce hugetlb fairness. But it is very
difficult to configure memory.max to keep overall consumption, including
anon, cache, slab etc. fair.
What we have had to resort to is to constantly poll hugetlb usage and
readjust memory.max. Similar procedure is done to other memory limits
(memory.low for e.g). However, this is rather cumbersome and buggy.
Furthermore, when there is a delay in memory limits correction, (for e.g
when hugetlb usage changes within consecutive runs of the userspace
agent), the system could be in an over/underprotected state.
This patch rectifies this issue by charging the memcg when the hugetlb
folio is utilized, and uncharging when the folio is freed (analogous to
the hugetlb controller). Note that we do not charge when the folio is
allocated to the hugetlb pool, because at this point it is not owned by
any memcg.
Some caveats to consider:
* This feature is only available on cgroup v2.
* There is no hugetlb pool management involved in the memory
controller. As stated above, hugetlb folios are only charged towards
the memory controller when it is used. Host overcommit management
has to consider it when configuring hard limits.
* Failure to charge towards the memcg results in SIGBUS. This could
happen even if the hugetlb pool still has pages (but the cgroup
limit is hit and reclaim attempt fails).
* When this feature is enabled, hugetlb pages contribute to memory
reclaim protection. low, min limits tuning must take into account
hugetlb memory.
* Hugetlb pages utilized while this option is not selected will not
be tracked by the memory controller (even if cgroup v2 is remounted
later on).
Link: https://lkml.kernel.org/r/20231006184629.155543-4-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tejun heo <tj@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
Gregory Price
|
ec47e25062 |
mm/migrate: remove unused mm argument from do_move_pages_to_node
This function does not actively use the mm_struct, it can be removed. Link: https://lkml.kernel.org/r/20231003144857.752952-2-gregory.price@memverge.com Signed-off-by: Gregory Price <gregory.price@memverge.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Gregory Price <gregory.price@memverge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Andrew Morton
|
5ef8f1b2b4 | Merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes. | ||
Sidhartha Kumar
|
a08c7193e4 |
mm/filemap: remove hugetlb special casing in filemap.c
Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.
To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.
========================= PERFORMANCE ======================================
Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.
Timing
aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s
6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s
6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s
x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s
6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s
6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s
aarch64:
workload - fallocate a 700GB file backed by huge pages
6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio
6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio
x86
workload - fallocate a 100GB file backed by huge pages
6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt
0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store
6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio
========================= TESTING ======================================
This patch passes libhugetlbfs tests and LTP hugetlb tests
********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********
Done executing testcases.
LTP Version: 20220527-178-g2761a81c4
page migration was also tested using Mike Kravetz's test program.[8]
[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Gregory Price
|
229e225376 |
mm/migrate: fix do_pages_move for compat pointers
do_pages_move does not handle compat pointers for the page list. correctly. Add in_compat_syscall check and appropriate get_user fetch when iterating the page list. It makes the syscall in compat mode (32-bit userspace, 64-bit kernel) work the same way as the native 32-bit syscall again, restoring the behavior before my broken commit |
||
|
Kefeng Wang
|
fa1df3f628 |
mm: migrate: remove isolated variable in add_page_for_migration()
Directly check the return of isolate_hugetlb() and folio_isolate_lru() to remove isolated variable, also setup err = -EBUSY in advance before isolation, and update err only when successfully queued for migration, which could help us to unify and simplify code a bit. Link: https://lkml.kernel.org/r/20230913095131.2426871-9-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
b426ed7889 |
mm: migrate: remove PageHead() check for HugeTLB in add_page_for_migration()
There is some different between hugeTLB and THP behave when passed the
address of a tail page, for THP, it will migrate the entire THP page, but
for HugeTLB, it will return -EACCES, or -ENOENT before commit
|
||
|
Kefeng Wang
|
d64cfccbc8 |
mm: migrate: use a folio in add_page_for_migration()
Use a folio in add_page_for_migration() to save compound_head() calls. Link: https://lkml.kernel.org/r/20230913095131.2426871-7-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
7e2a5e5ab2 |
mm: migrate: use __folio_test_movable()
Use __folio_test_movable(), no need to convert from folio to page again. Link: https://lkml.kernel.org/r/20230913095131.2426871-6-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
73eab3ca48 |
mm: migrate: convert migrate_misplaced_page() to migrate_misplaced_folio()
At present, numa balance only support base page and PMD-mapped THP, but we will expand to support to migrate large folio/pte-mapped THP in the future, it is better to make migrate_misplaced_page() to take a folio instead of a page, and rename it to migrate_misplaced_folio(), it is a preparation, also this remove several compound_head() calls. Link: https://lkml.kernel.org/r/20230913095131.2426871-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
2ac9e99f3b |
mm: migrate: convert numamigrate_isolate_page() to numamigrate_isolate_folio()
Rename numamigrate_isolate_page() to numamigrate_isolate_folio(), then make it takes a folio and use folio API to save compound_head() calls. Link: https://lkml.kernel.org/r/20230913095131.2426871-4-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
728be28fae |
mm: migrate: remove THP mapcount check in numamigrate_isolate_page()
The check of THP mapped by multiple processes was introduced by commit |
||
|
Kefeng Wang
|
a8ac4a767d |
mm: migrate: remove PageTransHuge check in numamigrate_isolate_page()
Patch series "mm: migrate: more folio conversion and unification", v3.
Convert more migrate functions to use a folio, it is also a preparation
for large folio migration support when balancing numa.
This patch (of 8):
The assert VM_BUG_ON_PAGE(order && !PageTransHuge(page), page) is not very
useful,
1) for a tail/base page, order = 0, for a head page, the order > 0 &&
PageTransHuge() is true
2) there is a PageCompound() check and only base page is handled in
do_numa_page(), and do_huge_pmd_numa_page() only handle PMD-mapped
THP
3) even though the page is a tail page, isolate_lru_page() will post
a warning, and fail to isolate the page
4) if large folio/pte-mapped THP migration supported in the future,
we could migrate the entire folio if numa fault on a tail page
so just remove the check.
Link: https://lkml.kernel.org/r/20230913095131.2426871-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20230913095131.2426871-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
David Hildenbrand
|
09c550508a |
mm/rmap: pass folio to hugepage_add_anon_rmap()
Let's pass a folio; we are always mapping the entire thing. Link: https://lkml.kernel.org/r/20230913125113.313322-7-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Ryan Roberts
|
935d4f0c6d |
mm: hugetlb: add huge page size param to set_huge_pte_at()
Patch series "Fix set_huge_pte_at() panic on arm64", v2. This series fixes a bug in arm64's implementation of set_huge_pte_at(), which can result in an unprivileged user causing a kernel panic. The problem was triggered when running the new uffd poison mm selftest for HUGETLB memory. This test (and the uffd poison feature) was merged for v6.5-rc7. Ideally, I'd like to get this fix in for v6.6 and I've cc'ed stable (correctly this time) to get it backported to v6.5, where the issue first showed up. Description of Bug ================== arm64's huge pte implementation supports multiple huge page sizes, some of which are implemented in the page table with multiple contiguous entries. So set_huge_pte_at() needs to work out how big the logical pte is, so that it can also work out how many physical ptes (or pmds) need to be written. It previously did this by grabbing the folio out of the pte and querying its size. However, there are cases when the pte being set is actually a swap entry. But this also used to work fine, because for huge ptes, we only ever saw migration entries and hwpoison entries. And both of these types of swap entries have a PFN embedded, so the code would grab that and everything still worked out. But over time, more calls to set_huge_pte_at() have been added that set swap entry types that do not embed a PFN. And this causes the code to go bang. The triggering case is for the uffd poison test, commit |
||
Linus Torvalds
|
df57721f9a |
Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 shadow stack support from Dave Hansen: "This is the long awaited x86 shadow stack support, part of Intel's Control-flow Enforcement Technology (CET). CET consists of two related security features: shadow stacks and indirect branch tracking. This series implements just the shadow stack part of this feature, and just for userspace. The main use case for shadow stack is providing protection against return oriented programming attacks. It works by maintaining a secondary (shadow) stack using a special memory type that has protections against modification. When executing a CALL instruction, the processor pushes the return address to both the normal stack and to the special permission shadow stack. Upon RET, the processor pops the shadow stack copy and compares it to the normal stack copy. For more information, refer to the links below for the earlier versions of this patch set" Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/ Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/ * tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits) x86/shstk: Change order of __user in type x86/ibt: Convert IBT selftest to asm x86/shstk: Don't retry vm_munmap() on -EINTR x86/kbuild: Fix Documentation/ reference x86/shstk: Move arch detail comment out of core mm x86/shstk: Add ARCH_SHSTK_STATUS x86/shstk: Add ARCH_SHSTK_UNLOCK x86: Add PTRACE interface for shadow stack selftests/x86: Add shadow stack test x86/cpufeatures: Enable CET CR4 bit for shadow stack x86/shstk: Wire in shadow stack interface x86: Expose thread features in /proc/$PID/status x86/shstk: Support WRSS for userspace x86/shstk: Introduce map_shadow_stack syscall x86/shstk: Check that signal frame is shadow stack mem x86/shstk: Check that SSP is aligned on sigreturn x86/shstk: Handle signals for shadow stack x86/shstk: Introduce routines modifying shstk x86/shstk: Handle thread shadow stack x86/shstk: Add user-mode shadow stack support ... |
||
|
Linus Torvalds
|
3d3dfeb3ae |
Merge tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
"Pretty quiet round for this release. This contains:
- Add support for zoned storage to ublk (Andreas, Ming)
- Series improving performance for drivers that mark themselves as
needing a blocking context for issue (Bart)
- Cleanup the flush logic (Chengming)
- sed opal keyring support (Greg)
- Fixes and improvements to the integrity support (Jinyoung)
- Add some exports for bcachefs that we can hopefully delete again in
the future (Kent)
- deadline throttling fix (Zhiguo)
- Series allowing building the kernel without buffer_head support
(Christoph)
- Sanitize the bio page adding flow (Christoph)
- Write back cache fixes (Christoph)
- MD updates via Song:
- Fix perf regression for raid0 large sequential writes (Jan)
- Fix split bio iostat for raid0 (David)
- Various raid1 fixes (Heinz, Xueshi)
- raid6test build fixes (WANG)
- Deprecate bitmap file support (Christoph)
- Fix deadlock with md sync thread (Yu)
- Refactor md io accounting (Yu)
- Various non-urgent fixes (Li, Yu, Jack)
- Various fixes and cleanups (Arnd, Azeem, Chengming, Damien, Li,
Ming, Nitesh, Ruan, Tejun, Thomas, Xu)"
* tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux: (113 commits)
block: use strscpy() to instead of strncpy()
block: sed-opal: keyring support for SED keys
block: sed-opal: Implement IOC_OPAL_REVERT_LSP
block: sed-opal: Implement IOC_OPAL_DISCOVERY
blk-mq: prealloc tags when increase tagset nr_hw_queues
blk-mq: delete redundant tagset map update when fallback
blk-mq: fix tags leak when shrink nr_hw_queues
ublk: zoned: support REQ_OP_ZONE_RESET_ALL
md: raid0: account for split bio in iostat accounting
md/raid0: Fix performance regression for large sequential writes
md/raid0: Factor out helper for mapping and submitting a bio
md raid1: allow writebehind to work on any leg device set WriteMostly
md/raid1: hold the barrier until handle_read_error() finishes
md/raid1: free the r1bio before waiting for blocked rdev
md/raid1: call free_r1bio() before allow_barrier() in raid_end_bio_io()
blk-cgroup: Fix NULL deref caused by blkg_policy_data being installed before init
drivers/rnbd: restore sysfs interface to rnbd-client
md/raid5-cache: fix null-ptr-deref for r5l_flush_stripe_to_raid()
raid6: test: only check for Altivec if building on powerpc hosts
raid6: test: make sure all intermediate and artifact files are .gitignored
...
|
||
|
Matthew Wilcox (Oracle)
|
d5db4f9df9 |
migrate: use folio_set_bh() instead of set_bh_page()
This function was converted before folio_set_bh() existed. Catch up to the new API. Link: https://lkml.kernel.org/r/20230713035512.4139457-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Tom Rix <trix@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
David Howells
|
0201ebf274 |
mm: merge folio_has_private()/filemap_release_folio() call pairs
Patch series "mm, netfs, fscache: Stop read optimisation when folio removed from pagecache", v7. This fixes an optimisation in fscache whereby we don't read from the cache for a particular file until we know that there's data there that we don't have in the pagecache. The problem is that I'm no longer using PG_fscache (aka PG_private_2) to indicate that the page is cached and so I don't get a notification when a cached page is dropped from the pagecache. The first patch merges some folio_has_private() and filemap_release_folio() pairs and introduces a helper, folio_needs_release(), to indicate if a release is required. The second patch is the actual fix. Following Willy's suggestions[1], it adds an AS_RELEASE_ALWAYS flag to an address_space that will make filemap_release_folio() always call ->release_folio(), even if PG_private/PG_private_2 aren't set. folio_needs_release() is altered to add a check for this. This patch (of 2): Make filemap_release_folio() check folio_has_private(). Then, in most cases, where a call to folio_has_private() is immediately followed by a call to filemap_release_folio(), we can get rid of the test in the pair. There are a couple of sites in mm/vscan.c that this can't so easily be done. In shrink_folio_list(), there are actually three cases (something different is done for incompletely invalidated buffers), but filemap_release_folio() elides two of them. In shrink_active_list(), we don't have have the folio lock yet, so the check allows us to avoid locking the page unnecessarily. A wrapper function to check if a folio needs release is provided for those places that still need to do it in the mm/ directory. This will acquire additional parts to the condition in a future patch. After this, the only remaining caller of folio_has_private() outside of mm/ is a check in fuse. Link: https://lkml.kernel.org/r/20230628104852.3391651-1-dhowells@redhat.com Link: https://lkml.kernel.org/r/20230628104852.3391651-2-dhowells@redhat.com Reported-by: Rohith Surabattula <rohiths.msft@gmail.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steve French <sfrench@samba.org> Cc: Shyam Prasad N <nspmangalore@gmail.com> Cc: Rohith Surabattula <rohiths.msft@gmail.com> Cc: Dave Wysochanski <dwysocha@redhat.com> Cc: Dominique Martinet <asmadeus@codewreck.org> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Xiubo Li <xiubli@redhat.com> Cc: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Christoph Hellwig
|
925c86a19b |
fs: add CONFIG_BUFFER_HEAD
Add a new config option that controls building the buffer_head code, and select it from all file systems and stacking drivers that need it. For the block device nodes and alternative iomap based buffered I/O path is provided when buffer_head support is not enabled, and iomap needs a a small tweak to define the IOMAP_F_BUFFER_HEAD flag to 0 to not call into the buffer_head code when it doesn't exist. Otherwise this is just Kconfig and ifdef changes. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20230801172201.1923299-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> |
||
Rick Edgecombe
|
161e393c0f |
mm: Make pte_mkwrite() take a VMA
The x86 Shadow stack feature includes a new type of memory called shadow stack. This shadow stack memory has some unusual properties, which requires some core mm changes to function properly. One of these unusual properties is that shadow stack memory is writable, but only in limited ways. These limits are applied via a specific PTE bit combination. Nevertheless, the memory is writable, and core mm code will need to apply the writable permissions in the typical paths that call pte_mkwrite(). Future patches will make pte_mkwrite() take a VMA, so that the x86 implementation of it can know whether to create regular writable or shadow stack mappings. But there are a couple of challenges to this. Modifying the signatures of each arch pte_mkwrite() implementation would be error prone because some are generated with macros and would need to be re-implemented. Also, some pte_mkwrite() callers operate on kernel memory without a VMA. So this can be done in a three step process. First pte_mkwrite() can be renamed to pte_mkwrite_novma() in each arch, with a generic pte_mkwrite() added that just calls pte_mkwrite_novma(). Next callers without a VMA can be moved to pte_mkwrite_novma(). And lastly, pte_mkwrite() and all callers can be changed to take/pass a VMA. Previous work pte_mkwrite() renamed pte_mkwrite_novma() and converted callers that don't have a VMA were to use pte_mkwrite_novma(). So now change pte_mkwrite() to take a VMA and change the remaining callers to pass a VMA. Apply the same changes for pmd_mkwrite(). No functional change. Suggested-by: David Hildenbrand <david@redhat.com> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/all/20230613001108.3040476-4-rick.p.edgecombe%40intel.com |
||
|
Matthew Wilcox (Oracle)
|
994ec4e29b |
mm: remove unnecessary pagevec includes
These files no longer need pagevec.h, mostly due to function declarations being moved out of it. Link: https://lkml.kernel.org/r/20230621164557.3510324-14-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Jan Glauber
|
0b52c42035 |
mm: fix shmem THP counters on migration
The per node numa_stat values for shmem don't change on page migration for
THP:
grep shmem /sys/fs/cgroup/machine.slice/.../memory.numa_stat:
shmem N0=1092616192 N1=10485760
shmem_thp N0=1092616192 N1=10485760
migratepages 9181 0 1:
shmem N0=0 N1=1103101952
shmem_thp N0=1092616192 N1=10485760
Fix that by updating shmem_thp counters likewise to shmem counters on page
migration.
[jglauber@digitalocean.com: use folio_test_pmd_mappable instead of folio_test_transhuge]
Link: https://lkml.kernel.org/r/20230622094720.510540-1-jglauber@digitalocean.com
Link: https://lkml.kernel.org/r/20230619103351.234837-1-jglauber@digitalocean.com
Signed-off-by: Jan Glauber <jglauber@digitalocean.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Ryan Roberts
|
c33c794828 |
mm: ptep_get() conversion
Convert all instances of direct pte_t* dereferencing to instead use ptep_get() helper. This means that by default, the accesses change from a C dereference to a READ_ONCE(). This is technically the correct thing to do since where pgtables are modified by HW (for access/dirty) they are volatile and therefore we should always ensure READ_ONCE() semantics. But more importantly, by always using the helper, it can be overridden by the architecture to fully encapsulate the contents of the pte. Arch code is deliberately not converted, as the arch code knows best. It is intended that arch code (arm64) will override the default with its own implementation that can (e.g.) hide certain bits from the core code, or determine young/dirty status by mixing in state from another source. Conversion was done using Coccinelle: ---- // $ make coccicheck \ // COCCI=ptepget.cocci \ // SPFLAGS="--include-headers" \ // MODE=patch virtual patch @ depends on patch @ pte_t *v; @@ - *v + ptep_get(v) ---- Then reviewed and hand-edited to avoid multiple unnecessary calls to ptep_get(), instead opting to store the result of a single call in a variable, where it is correct to do so. This aims to negate any cost of READ_ONCE() and will benefit arch-overrides that may be more complex. Included is a fix for an issue in an earlier version of this patch that was pointed out by kernel test robot. The issue arose because config MMU=n elides definition of the ptep helper functions, including ptep_get(). HUGETLB_PAGE=n configs still define a simple huge_ptep_clear_flush() for linking purposes, which dereferences the ptep. So when both configs are disabled, this caused a build error because ptep_get() is not defined. Fix by continuing to do a direct dereference when MMU=n. This is safe because for this config the arch code cannot be trying to virtualize the ptes because none of the ptep helpers are defined. Link: https://lkml.kernel.org/r/20230612151545.3317766-4-ryan.roberts@arm.com Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/oe-kbuild-all/202305120142.yXsNEo6H-lkp@intel.com/ Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Potapenko <glider@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Dave Airlie <airlied@gmail.com> Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ian Rogers <irogers@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Hugh Dickins
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04dee9e85c |
mm/various: give up if pte_offset_map[_lock]() fails
Following the examples of nearby code, various functions can just give up if pte_offset_map() or pte_offset_map_lock() fails. And there's no need for a preliminary pmd_trans_unstable() or other such check, since such cases are now safely handled inside. Link: https://lkml.kernel.org/r/7b9bd85d-1652-cbf2-159d-f503b45e5b@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zack Rusin <zackr@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Hugh Dickins
|
0cb8fd4d14 |
mm/migrate: remove cruft from migration_entry_wait()s
migration_entry_wait_on_locked() does not need to take a mapped pte pointer, its callers can do the unmap first. Annotate it with __releases(ptl) to reduce sparse warnings. Fold __migration_entry_wait_huge() into migration_entry_wait_huge(). Fold __migration_entry_wait() into migration_entry_wait(), preferring the tighter pte_offset_map_lock() to pte_offset_map() and pte_lockptr(). Link: https://lkml.kernel.org/r/b0e2a532-cdf2-561b-e999-f3b13b8d6d3@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zack Rusin <zackr@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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4e096ae180 |
mm: convert migrate_pages() to work on folios
Almost all of the callers & implementors of migrate_pages() were already converted to use folios. compaction_alloc() & compaction_free() are trivial to convert a part of this patch and not worth splitting out. Link: https://lkml.kernel.org/r/20230513001101.276972-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Huang Ying
|
124abced64 |
migrate_pages_batch: simplify retrying and failure counting of large folios
After recent changes to the retrying and failure counting in migrate_pages_batch(), it was found that it's unnecessary to count retrying and failure for normal, large, and THP folios separately. Because we don't use retrying and failure number of large folios directly. So, in this patch, we simplified retrying and failure counting of large folios via counting retrying and failure of normal and large folios together. This results in the reduced line number. Previously, in migrate_pages_batch we need to track whether the source folio is large/THP before splitting. So is_large is used to cache folio_test_large() result. Now, we don't need that variable any more because we don't count retrying and failure of large folios (only counting that of THP folios). So, in this patch, is_large is removed to simplify the code. This is just code cleanup, no functionality changes are expected. Link: https://lkml.kernel.org/r/20230510031829.11513-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Douglas Anderson
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4bb6dc79d9 |
migrate_pages: avoid blocking for IO in MIGRATE_SYNC_LIGHT
The MIGRATE_SYNC_LIGHT mode is intended to block for things that will finish quickly but not for things that will take a long time. Exactly how long is too long is not well defined, but waits of tens of milliseconds is likely non-ideal. When putting a Chromebook under memory pressure (opening over 90 tabs on a 4GB machine) it was fairly easy to see delays waiting for some locks in the kcompactd code path of > 100 ms. While the laptop wasn't amazingly usable in this state, it was still limping along and this state isn't something artificial. Sometimes we simply end up with a lot of memory pressure. Putting the same Chromebook under memory pressure while it was running Android apps (though not stressing them) showed a much worse result (NOTE: this was on a older kernel but the codepaths here are similar). Android apps on ChromeOS currently run from a 128K-block, zlib-compressed, loopback-mounted squashfs disk. If we get a page fault from something backed by the squashfs filesystem we could end up holding a folio lock while reading enough from disk to decompress 128K (and then decompressing it using the somewhat slow zlib algorithms). That reading goes through the ext4 subsystem (because it's a loopback mount) before eventually ending up in the block subsystem. This extra jaunt adds extra overhead. Without much work I could see cases where we ended up blocked on a folio lock for over a second. With more extreme memory pressure I could see up to 25 seconds. We considered adding a timeout in the case of MIGRATE_SYNC_LIGHT for the two locks that were seen to be slow [1] and that generated much discussion. After discussion, it was decided that we should avoid waiting for the two locks during MIGRATE_SYNC_LIGHT if they were being held for IO. We'll continue with the unbounded wait for the more full SYNC modes. With this change, I couldn't see any slow waits on these locks with my previous testcases. NOTE: The reason I stated digging into this originally isn't because some benchmark had gone awry, but because we've received in-the-field crash reports where we have a hung task waiting on the page lock (which is the equivalent code path on old kernels). While the root cause of those crashes is likely unrelated and won't be fixed by this patch, analyzing those crash reports did point out these very long waits seemed like something good to fix. With this patch we should no longer hang waiting on these locks, but presumably the system will still be in a bad shape and hang somewhere else. [1] https://lore.kernel.org/r/20230421151135.v2.1.I2b71e11264c5c214bc59744b9e13e4c353bc5714@changeid Link: https://lkml.kernel.org/r/20230428135414.v3.1.Ia86ccac02a303154a0b8bc60567e7a95d34c96d3@changeid Signed-off-by: Douglas Anderson <dianders@chromium.org> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Hillf Danton <hdanton@sina.com> Cc: Gao Xiang <hsiangkao@linux.alibaba.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Gao Xiang <hsiangkao@linux.alibaba.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Linus Torvalds
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22b8cc3e78 |
Merge tag 'x86_mm_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 LAM (Linear Address Masking) support from Dave Hansen: "Add support for the new Linear Address Masking CPU feature. This is similar to ARM's Top Byte Ignore and allows userspace to store metadata in some bits of pointers without masking it out before use" * tag 'x86_mm_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm/iommu/sva: Do not allow to set FORCE_TAGGED_SVA bit from outside x86/mm/iommu/sva: Fix error code for LAM enabling failure due to SVA selftests/x86/lam: Add test cases for LAM vs thread creation selftests/x86/lam: Add ARCH_FORCE_TAGGED_SVA test cases for linear-address masking selftests/x86/lam: Add inherit test cases for linear-address masking selftests/x86/lam: Add io_uring test cases for linear-address masking selftests/x86/lam: Add mmap and SYSCALL test cases for linear-address masking selftests/x86/lam: Add malloc and tag-bits test cases for linear-address masking x86/mm/iommu/sva: Make LAM and SVA mutually exclusive iommu/sva: Replace pasid_valid() helper with mm_valid_pasid() mm: Expose untagging mask in /proc/$PID/status x86/mm: Provide arch_prctl() interface for LAM x86/mm: Reduce untagged_addr() overhead for systems without LAM x86/uaccess: Provide untagged_addr() and remove tags before address check mm: Introduce untagged_addr_remote() x86/mm: Handle LAM on context switch x86: CPUID and CR3/CR4 flags for Linear Address Masking x86: Allow atomic MM_CONTEXT flags setting x86/mm: Rework address range check in get_user() and put_user() |
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David Hildenbrand
|
f3ebdf042d |
mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
Staring at the comment "Recheck VMA as permissions can change since
migration started" in remove_migration_pte() can result in confusion,
because if the source PTE/PMD indicates write permissions, then there
should be no need to check VMA write permissions when restoring migration
entries or PTE-mapping a PMD.
Commit
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Huang Ying
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851ae64246 |
migrate_pages_batch: fix statistics for longterm pin retry
In commit |
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David Hildenbrand
|
3c811f7883 |
mm/migrate: revert "mm/migrate: fix wrongly apply write bit after mkdirty on sparc64"
This reverts commit |
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Anshuman Khandual
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1da28f1b5a |
mm/migrate: drop pte_mkhuge() in remove_migration_pte()
Since the following commit, arch_make_huge_pte() should be used directly
in generic memory subsystem as a platform provided page table helper,
instead of pte_mkhuge(). This just drops pte_mkhuge() from
remove_migration_pte(), which has now become redundant.
'commit
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Kirill A. Shutemov
|
428e106ae1 |
mm: Introduce untagged_addr_remote()
untagged_addr() removes tags/metadata from the address and brings it to the canonical form. The helper is implemented on arm64 and sparc. Both of them do untagging based on global rules. However, Linear Address Masking (LAM) on x86 introduces per-process settings for untagging. As a result, untagged_addr() is now only suitable for untagging addresses for the current proccess. The new helper untagged_addr_remote() has to be used when the address targets remote process. It requires the mmap lock for target mm to be taken. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Alexander Potapenko <glider@google.com> Link: https://lore.kernel.org/all/20230312112612.31869-6-kirill.shutemov%40linux.intel.com |
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Huang Ying
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2ef7dbb269 |
migrate_pages: try migrate in batch asynchronously firstly
When we have locked more than one folios, we cannot wait the lock or bit
(e.g., page lock, buffer head lock, writeback bit) synchronously.
Otherwise deadlock may be triggered. This make it hard to batch the
synchronous migration directly.
This patch re-enables batching synchronous migration via trying to migrate
in batch asynchronously firstly. And any folios that are failed to be
migrated asynchronously will be migrated synchronously one by one.
Test shows that this can restore the TLB flushing batching performance for
synchronous migration effectively.
Link: https://lkml.kernel.org/r/20230303030155.160983-4-ying.huang@intel.com
Fixes:
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Huang Ying
|
a21d213321 |
migrate_pages: move split folios processing out of migrate_pages_batch()
To simplify the code logic and reduce the line number.
Link: https://lkml.kernel.org/r/20230303030155.160983-3-ying.huang@intel.com
Fixes:
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Huang Ying
|
fb3592c41a |
migrate_pages: fix deadlock in batched migration
Patch series "migrate_pages: fix deadlock in batched synchronous
migration", v2.
Two deadlock bugs were reported for the migrate_pages() batching series.
Thanks Hugh and Pengfei. Analysis shows that if we have locked some other
folios except the one we are migrating, it's not safe in general to wait
synchronously, for example, to wait the writeback to complete or wait to
lock the buffer head.
So 1/3 fixes the deadlock in a simple way, where the batching support for
the synchronous migration is disabled. The change is straightforward and
easy to be understood. While 3/3 re-introduce the batching for
synchronous migration via trying to migrate asynchronously in batch
optimistically, then fall back to migrate synchronously one by one for
fail-to-migrate folios. Test shows that this can restore the TLB flushing
batching performance for synchronous migration effectively.
This patch (of 3):
Two deadlock bugs were reported for the migrate_pages() batching series.
Thanks Hugh and Pengfei! For example, in the following deadlock trace
snippet,
INFO: task kworker/u4:0:9 blocked for more than 147 seconds.
Not tainted 6.2.0-rc4-kvm+ #1314
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0 state:D stack:0 pid:9 ppid:2 flags:0x00004000
Workqueue: loop4 loop_rootcg_workfn
Call Trace:
<TASK>
__schedule+0x43b/0xd00
schedule+0x6a/0xf0
io_schedule+0x4a/0x80
folio_wait_bit_common+0x1b5/0x4e0
? __pfx_wake_page_function+0x10/0x10
__filemap_get_folio+0x73d/0x770
shmem_get_folio_gfp+0x1fd/0xc80
shmem_write_begin+0x91/0x220
generic_perform_write+0x10e/0x2e0
__generic_file_write_iter+0x17e/0x290
? generic_write_checks+0x12b/0x1a0
generic_file_write_iter+0x97/0x180
? __sanitizer_cov_trace_const_cmp4+0x1a/0x20
do_iter_readv_writev+0x13c/0x210
? __sanitizer_cov_trace_const_cmp4+0x1a/0x20
do_iter_write+0xf6/0x330
vfs_iter_write+0x46/0x70
loop_process_work+0x723/0xfe0
loop_rootcg_workfn+0x28/0x40
process_one_work+0x3cc/0x8d0
worker_thread+0x66/0x630
? __pfx_worker_thread+0x10/0x10
kthread+0x153/0x190
? __pfx_kthread+0x10/0x10
ret_from_fork+0x29/0x50
</TASK>
INFO: task repro:1023 blocked for more than 147 seconds.
Not tainted 6.2.0-rc4-kvm+ #1314
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:repro state:D stack:0 pid:1023 ppid:360 flags:0x00004004
Call Trace:
<TASK>
__schedule+0x43b/0xd00
schedule+0x6a/0xf0
io_schedule+0x4a/0x80
folio_wait_bit_common+0x1b5/0x4e0
? compaction_alloc+0x77/0x1150
? __pfx_wake_page_function+0x10/0x10
folio_wait_bit+0x30/0x40
folio_wait_writeback+0x2e/0x1e0
migrate_pages_batch+0x555/0x1ac0
? __pfx_compaction_alloc+0x10/0x10
? __pfx_compaction_free+0x10/0x10
? __this_cpu_preempt_check+0x17/0x20
? lock_is_held_type+0xe6/0x140
migrate_pages+0x100e/0x1180
? __pfx_compaction_free+0x10/0x10
? __pfx_compaction_alloc+0x10/0x10
compact_zone+0xe10/0x1b50
? lock_is_held_type+0xe6/0x140
? check_preemption_disabled+0x80/0xf0
compact_node+0xa3/0x100
? __sanitizer_cov_trace_const_cmp8+0x1c/0x30
? _find_first_bit+0x7b/0x90
sysctl_compaction_handler+0x5d/0xb0
proc_sys_call_handler+0x29d/0x420
proc_sys_write+0x2b/0x40
vfs_write+0x3a3/0x780
ksys_write+0xb7/0x180
__x64_sys_write+0x26/0x30
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7f3a2471f59d
RSP: 002b:00007ffe567f7288 EFLAGS: 00000217 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3a2471f59d
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007ffe567f72a0 R08: 0000000000000010 R09: 0000000000000010
R10: 0000000000000010 R11: 0000000000000217 R12: 00000000004012e0
R13: 00007ffe567f73e0 R14: 0000000000000000 R15: 0000000000000000
</TASK>
The page migration task has held the lock of the shmem folio A, and is
waiting the writeback of the folio B of the file system on the loop block
device to complete. While the loop worker task which writes back the
folio B is waiting to lock the shmem folio A, because the folio A backs
the folio B in the loop device. Thus deadlock is triggered.
In general, if we have locked some other folios except the one we are
migrating, it's not safe to wait synchronously, for example, to wait the
writeback to complete or wait to lock the buffer head.
To fix the deadlock, in this patch, we avoid to batch the page migration
except for MIGRATE_ASYNC mode. In MIGRATE_ASYNC mode, synchronous waiting
is avoided.
The fix can be improved further. We will do that as soon as possible.
Link: https://lkml.kernel.org/r/20230303030155.160983-1-ying.huang@intel.com
Link: https://lore.kernel.org/linux-mm/87a6c8c-c5c1-67dc-1e32-eb30831d6e3d@google.com/
Link: https://lore.kernel.org/linux-mm/874jrg7kke.fsf@yhuang6-desk2.ccr.corp.intel.com/
Link: https://lore.kernel.org/linux-mm/20230227110614.dngdub2j3exr6dfp@quack3/
Link: https://lkml.kernel.org/r/20230303030155.160983-2-ying.huang@intel.com
Fixes:
|