| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
"(CONFIG_SHMEM)&&(!(CONFIG_SHMEM))"
The value of “.fs_flags” in line 4608 is a dead code which will never
be implemented，because its conditions of line 47 "#ifdef CONFIG_SHMEM"
and line 4607 are mutually exclusive. It is recommended to delete
redundant code.
Link: https://lkml.kernel.org/r/20230906045012.14999-1-sunying@nj.iscas.ac.cn
Signed-off-by: Ying Sun <sunying@nj.iscas.ac.cn>
Suggested-by: Yanjie Ren <renyanjie01@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
If panic is enable,the err information will not be printed before bugon,
So swap it. Print the return value of PTR_ERR(pgdat->kswapd) also.
Link: https://lkml.kernel.org/r/20230906083700.181-1-angus.chen@jaguarmicro.com
Signed-off-by: Angus Chen <angus.chen@jaguarmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
There is a similar pr_info in free_area_init_node(), so remove the
redundant pr_info.
before:
[ 0.006314] Initializing node 0 as memoryless
[ 0.006445] Initmem setup node 0 as memoryless
[ 0.006450] Initmem setup node 1 [mem 0x0000000000001000-0x000000003fffffff]
[ 0.006453] Initmem setup node 2 [mem 0x0000000040000000-0x000000007ffd7fff]
[ 0.006454] Initializing node 3 as memoryless
[ 0.006584] Initmem setup node 3 as memoryless
[ 0.006585] Initmem setup node 4 [mem 0x0000000100000000-0x00000001bfffffff]
[ 0.006586] Initmem setup node 5 [mem 0x00000001c0000000-0x00000001ffffffff]
[ 0.006587] Initmem setup node 6 [mem 0x0000000200000000-0x000000023fffffff]
after:
[ 0.004147] Initmem setup node 0 as memoryless
[ 0.004148] Initmem setup node 1 [mem 0x0000000000001000-0x000000003fffffff]
[ 0.004150] Initmem setup node 2 [mem 0x0000000040000000-0x000000007ffd7fff]
[ 0.004154] Initmem setup node 3 as memoryless
[ 0.004155] Initmem setup node 4 [mem 0x0000000100000000-0x00000001bfffffff]
[ 0.004156] Initmem setup node 5 [mem 0x00000001c0000000-0x00000001ffffffff]
[ 0.004157] Initmem setup node 6 [mem 0x0000000200000000-0x000000023fffffff]
Link: https://lkml.kernel.org/r/20230906091113.4029983-1-yajun.deng@linux.dev
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In vmemmap_remap_free(), a new head vmemmap page is allocated to avoid
breaking a contiguous block of struct page memory, however, the allocation
can always fail when the given node is movable node. Remove the
__GFP_THISNODE to help avoid fragmentation.
Link: https://lkml.kernel.org/r/20230906093157.9737-1-yuancan@huawei.com
Signed-off-by: Yuan Can <yuancan@huawei.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Suggested-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
expand_upwards() and expand_downwards() will return -EFAULT if VM_GROWSUP
or VM_GROWSDOWN is not correctly set in vma->vm_flags, however in
!CONFIG_STACK_GROWSUP case, expand_stack_locked() returns -EINVAL first if
!(vma->vm_flags & VM_GROWSDOWN) before calling expand_downwards(), to keep
the consistency with CONFIG_STACK_GROWSUP case, remove this check.
The usages of this function are as below:
A:fs/exec.c
ret = expand_stack_locked(vma, stack_base);
if (ret)
ret = -EFAULT;
or
B:mm/memory.c mm/mmap.c
if (expand_stack_locked(vma, addr))
return NULL;
which means the return value will not propagate to other places, so I
believe there is no user-visible effects of this change, and it's
unnecessary to backport to earlier versions.
Link: https://lkml.kernel.org/r/20230906103312.645712-1-xiujianfeng@huaweicloud.com
Fixes: f440fa1ac955 ("mm: make find_extend_vma() fail if write lock not held")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
tracepoint
damon_aggregateed tracepoint is receiving 'struct target *', but doesn't
use it. Remove it from the prototype.
Link: https://lkml.kernel.org/r/20230907022929.91361-12-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The comment on damon_set_attrs() says it should not be called while the
kdamond is running, but now some DAMON modules like sysfs interface and
DAMON_RECLAIM call it from after_aggregation() and/or
after_wmarks_check() callbacks for online tuning. Update the comment.
Link: https://lkml.kernel.org/r/20230907022929.91361-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Out of zswap's 3 allocators, zsmalloc is the clear superior in terms of
memory utilization, both in theory and as observed in practice, with its
high storage density and low internal fragmentation. zsmalloc is also
more actively developed and maintained, since it is the allocator of
choice for zswap for many users, as well as the only allocator for zram.
A historical objection to the selection of zsmalloc as the default
allocator for zswap is its lack of writeback capability. However, this
has changed, with the zsmalloc writeback patchset, and the subsequent
zswap LRU refactor. With this, there is not a lot of good reasons to keep
zbud, an otherwise inferior allocator, as the default instead of zswap.
This patch changes the default allocator to zsmalloc. The only exception
is on settings without MMU, in which case zbud will remain as the default.
Link: https://lkml.kernel.org/r/20230908235115.2943486-1-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
For the stack move happening in shift_arg_pages(), the move is happening
within the same VMA which spans the old and new ranges.
In case the aligned address happens to fall within that VMA, allow such
moves and don't abort the mremap alignment optimization.
In the regular non-stack mremap case, we cannot allow any such moves as
will end up destroying some part of the mapping (either the source of the
move, or part of the existing mapping). So just avoid it for stack moves.
Link: https://lkml.kernel.org/r/20230903151328.2981432-3-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Optimize mremap during mutual alignment within PMD", v6.
This patchset optimizes the start addresses in move_page_tables() and
tests the changes. It addresses a warning [1] that occurs due to a
downward, overlapping move on a mutually-aligned offset within a PMD
during exec. By initiating the copy process at the PMD level when such
alignment is present, we can prevent this warning and speed up the copying
process at the same time. Linus Torvalds suggested this idea. Check the
individual patches for more details. [1]
https://lore.kernel.org/all/ZB2GTBD%2FLWTrkOiO@dhcp22.suse.cz/
This patch (of 7):
Recently, we see reports [1] of a warning that triggers due to
move_page_tables() doing a downward and overlapping move on a
mutually-aligned offset within a PMD. By mutual alignment, I mean the
source and destination addresses of the mremap are at the same offset
within a PMD.
This mutual alignment along with the fact that the move is downward is
sufficient to cause a warning related to having an allocated PMD that does
not have PTEs in it.
This warning will only trigger when there is mutual alignment in the move
operation. A solution, as suggested by Linus Torvalds [2], is to initiate
the copy process at the PMD level whenever such alignment is present.
Implementing this approach will not only prevent the warning from being
triggered, but it will also optimize the operation as this method should
enhance the speed of the copy process whenever there's a possibility to
start copying at the PMD level.
Some more points:
a. The optimization can be done only when both the source and
destination of the mremap do not have anything mapped below it up to a
PMD boundary. I add support to detect that.
b. #1 is not a problem for the call to move_page_tables() from exec.c as
nothing is expected to be mapped below the source. However, for
non-overlapping mutually aligned moves as triggered by mremap(2), I
added support for checking such cases.
c. I currently only optimize for PMD moves, in the future I/we can build
on this work and do PUD moves as well if there is a need for this. But I
want to take it one step at a time.
d. We need to be careful about mremap of ranges within the VMA itself.
For this purpose, I added checks to determine if the address after
alignment falls within its VMA itself.
[1] https://lore.kernel.org/all/ZB2GTBD%2FLWTrkOiO@dhcp22.suse.cz/
[2] https://lore.kernel.org/all/CAHk-=whd7msp8reJPfeGNyt0LiySMT0egExx3TVZSX3Ok6X=9g@mail.gmail.com/
Link: https://lkml.kernel.org/r/20230903151328.2981432-1-joel@joelfernandes.org
Link: https://lkml.kernel.org/r/20230903151328.2981432-2-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The decreasing of hugetlb pages number failed with the following message
given:
sh: page allocation failure: order:0, mode:0x204cc0(GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_THISNODE)
CPU: 1 PID: 112 Comm: sh Not tainted 6.5.0-rc7-... #45
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace.part.6+0x84/0xe4
show_stack+0x18/0x24
dump_stack_lvl+0x48/0x60
dump_stack+0x18/0x24
warn_alloc+0x100/0x1bc
__alloc_pages_slowpath.constprop.107+0xa40/0xad8
__alloc_pages+0x244/0x2d0
hugetlb_vmemmap_restore+0x104/0x1e4
__update_and_free_hugetlb_folio+0x44/0x1f4
update_and_free_hugetlb_folio+0x20/0x68
update_and_free_pages_bulk+0x4c/0xac
set_max_huge_pages+0x198/0x334
nr_hugepages_store_common+0x118/0x178
nr_hugepages_store+0x18/0x24
kobj_attr_store+0x18/0x2c
sysfs_kf_write+0x40/0x54
kernfs_fop_write_iter+0x164/0x1dc
vfs_write+0x3a8/0x460
ksys_write+0x6c/0x100
__arm64_sys_write+0x1c/0x28
invoke_syscall+0x44/0x100
el0_svc_common.constprop.1+0x6c/0xe4
do_el0_svc+0x38/0x94
el0_svc+0x28/0x74
el0t_64_sync_handler+0xa0/0xc4
el0t_64_sync+0x174/0x178
Mem-Info:
...
The reason is that the hugetlb pages being released are allocated from
movable nodes, and with hugetlb_optimize_vmemmap enabled, vmemmap pages
need to be allocated from the same node during the hugetlb pages
releasing. With GFP_KERNEL and __GFP_THISNODE set, allocating from movable
node is always failed. Fix this problem by removing __GFP_THISNODE.
Link: https://lkml.kernel.org/r/20230905124503.24899-1-yuancan@huawei.com
Fixes: ad2fa3717b74 ("mm: hugetlb: alloc the vmemmap pages associated with each HugeTLB page")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Use this_cpu_try_cmpxchg instead of this_cpu_cmpxchg (*ptr, old, new) ==
old in mod_zone_state and mod_node_state. x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg (and
related move instruction in front of cmpxchg).
Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails. There is no need to re-read the value in the loop.
No functional change intended.
Link: https://lkml.kernel.org/r/20230904150917.8318-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The one caller of DAX lock/unlock page already calls compound_head(), so
use page_folio() instead, then use a folio throughout the DAX code to
remove uses of page->mapping and page->index.
[jane.chu@oracle.com: add comment to mf_generic_kill_procss(), simplify mf_generic_kill_procs:folio initialization]
Link: https://lkml.kernel.org/r/20230908222336.186313-1-jane.chu@oracle.com
Link: https://lkml.kernel.org/r/20230822231314.349200-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jane Chu <jane.chu@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The feature got retired in f1a7941243c1 ("mm: convert mm's rss stats into
percpu_counter"), but the patch failed to fully clean it up.
Link: https://lkml.kernel.org/r/20230823170556.2281747-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In skip_cma(), we can use folio_migratetype() to replace
get_pageblock_migratetype().
Link: https://lkml.kernel.org/r/20230825075735.52436-1-user@VERNHAO-MC1
Signed-off-by: Vern Hao <vernhao@tencent.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
si_mem_available() needlessly places LRU statistics into an array before
retrieving only two of them, simply access those directly.
In addition, refactor the code so that the blocks of code which calculate
the page cache and reclaimable components each resemble one another to
clearly indicate we cap both against wmark_low in the same fashion.
Link: https://lkml.kernel.org/r/20230827110848.43510-1-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In set_nr_huge_pages(), local variable "count" is used to record
persistent_huge_pages(), but when it cames to nodes huge page allocation,
the semantics changes to nr_huge_pages. When there exists surplus huge
pages and using the interface under
/sys/devices/system/node/node*/hugepages to change huge page pool size,
this difference can result in the allocation of an unexpected number of
huge pages.
Steps to reproduce the bug:
Starting with:
Node 0 Node 1 Total
HugePages_Total 0.00 0.00 0.00
HugePages_Free 0.00 0.00 0.00
HugePages_Surp 0.00 0.00 0.00
create 100 huge pages in Node 0 and consume it, then set Node 0 's
nr_hugepages to 0.
yields:
Node 0 Node 1 Total
HugePages_Total 200.00 0.00 200.00
HugePages_Free 0.00 0.00 0.00
HugePages_Surp 200.00 0.00 200.00
write 100 to Node 1's nr_hugepages
echo 100 > /sys/devices/system/node/node1/\
hugepages/hugepages-2048kB/nr_hugepages
gets:
Node 0 Node 1 Total
HugePages_Total 200.00 400.00 600.00
HugePages_Free 0.00 400.00 400.00
HugePages_Surp 200.00 0.00 200.00
Kernel is expected to create only 100 huge pages and it gives 200.
Link: https://lkml.kernel.org/r/20230829033343.467779-1-xueshi.hu@smartx.com
Fixes: 9a30523066cd ("hugetlb: add per node hstate attributes")
Signed-off-by: Xueshi Hu <xueshi.hu@smartx.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Currently, vmemmap optimization of hugetlb pages is performed before the
hugetlb flag (previously hugetlb destructor) is set identifying it as a
hugetlb folio. This means there is a window of time where an ordinary
folio does not have all associated vmemmap present. The core mm only
expects vmemmap to be potentially optimized for hugetlb and device dax.
This can cause problems in code such as memory error handling that may
want to write to tail struct pages.
There is only one call to perform hugetlb vmemmap optimization today. To
fix this issue, simply set the hugetlb flag before that call.
There was a similar issue in the free hugetlb path that was previously
addressed. The two routines that optimize or restore hugetlb vmemmap
should only be passed hugetlb folios/pages. To catch any callers not
following this rule, add VM_WARN_ON calls to the routines. In the hugetlb
free code paths, some calls could be made to restore vmemmap after
clearing the hugetlb flag. This was 'safe' as in these cases vmemmap was
already present and the call was a NOOP. However, for consistency these
calls where eliminated so that we can add the VM_WARN_ON checks.
Link: https://lkml.kernel.org/r/20230829213734.69673-1-mike.kravetz@oracle.com
Fixes: f41f2ed43ca5 ("mm: hugetlb: free the vmemmap pages associated with each HugeTLB page")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Usama Arif <usama.arif@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Fix insert_vm_struct() so that only accounted memory is unaccounted if
vma_link() fails.
Link: https://lkml.kernel.org/r/20230830004324.16101-1-anthony.yznaga@oracle.com
Fixes: d4af56c5c7c6 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Fix mremap so that only accounted memory is unaccounted if the mapping is
expandable but vma_merge() fails.
Link: https://lkml.kernel.org/r/20230830004549.16131-1-anthony.yznaga@oracle.com
Fixes: fdbef6149135 ("mm/mremap: don't account pages in vma_to_resize()")
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
target order
We always do zone_watermark_ok check and compaction_suitable check
together to test if compaction for target order should be ran. Factor
these code out to remove repeat code.
Link: https://lkml.kernel.org/r/20230901155141.249860-7-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We do proactive compaction with order == -1 via
1. /proc/sys/vm/compact_memory
2. /sys/devices/system/node/nodex/compact
3. /proc/sys/vm/compaction_proactiveness
Add missed situation in which order == -1.
Link: https://lkml.kernel.org/r/20230901155141.249860-6-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
reset_isolation_suitable
We have compact_blockskip_flush check in __reset_isolation_suitable, just
remove repeat check before __reset_isolation_suitable in
compact_blockskip_flush.
Link: https://lkml.kernel.org/r/20230901155141.249860-5-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In strict mode, we should return 0 if there is any hole in pageblock. If
we successfully isolated pages at beginning at pageblock and then have a
bogus compound_order outside pageblock in next page. We will abort search
loop with blockpfn > end_pfn. Although we will limit blockpfn to end_pfn,
we will treat it as a successful isolation in strict mode as blockpfn is
not < end_pfn and return partial isolated pages. Then
isolate_freepages_range may success unexpectly with hole in isolated
range.
Link: https://lkml.kernel.org/r/20230901155141.249860-4-shikemeng@huaweicloud.com
Fixes: 9fcd6d2e052e ("mm, compaction: skip compound pages by order in free scanner")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
move_freelist_{head}/{tail}
We use move_freelist_head after list_for_each_entry_reverse to skip recent
pages. And there is no need to do actual move if all freepages are
searched in list_for_each_entry_reverse, e.g. freepage point to first
page in freelist. It's more intuitively to call list_is_first with list
entry as the first argument and list head as the second argument to check
if list entry is the first list entry instead of call list_is_last with
list entry and list head passed in reverse.
Similarly, call list_is_last in move_freelist_tail is more intuitively.
Link: https://lkml.kernel.org/r/20230901155141.249860-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Fixes and cleanups to compaction", v3.
This is a series to do fix and clean up to compaction.
Patch 1-2 fix and clean up freepage list operation.
Patch 3-4 fix and clean up isolation of freepages
Patch 7 factor code to check if compaction is needed for allocation order.
More details can be found in respective patches.
This patch (of 6):
The freepage is chained with buddy_list in freelist head. Use buddy_list
instead of lru to correct the list operation.
Link: https://lkml.kernel.org/r/20230901155141.249860-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20230901155141.249860-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"Fourteen hotfixes, eleven of which are cc:stable. The remainder
pertain to issues which were introduced after 6.5"
* tag 'mm-hotfixes-stable-2023-10-01-08-34' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
Crash: add lock to serialize crash hotplug handling
selftests/mm: fix awk usage in charge_reserved_hugetlb.sh and hugetlb_reparenting_test.sh that may cause error
mm: mempolicy: keep VMA walk if both MPOL_MF_STRICT and MPOL_MF_MOVE are specified
mm/damon/vaddr-test: fix memory leak in damon_do_test_apply_three_regions()
mm, memcg: reconsider kmem.limit_in_bytes deprecation
mm: zswap: fix potential memory corruption on duplicate store
arm64: hugetlb: fix set_huge_pte_at() to work with all swap entries
mm: hugetlb: add huge page size param to set_huge_pte_at()
maple_tree: add MAS_UNDERFLOW and MAS_OVERFLOW states
maple_tree: add mas_is_active() to detect in-tree walks
nilfs2: fix potential use after free in nilfs_gccache_submit_read_data()
mm: abstract moving to the next PFN
mm: report success more often from filemap_map_folio_range()
fs: binfmt_elf_efpic: fix personality for ELF-FDPIC
|
|
specified
When calling mbind() with MPOL_MF_{MOVE|MOVEALL} | MPOL_MF_STRICT, kernel
should attempt to migrate all existing pages, and return -EIO if there is
misplaced or unmovable page. Then commit 6f4576e3687b ("mempolicy: apply
page table walker on queue_pages_range()") messed up the return value and
didn't break VMA scan early ianymore when MPOL_MF_STRICT alone. The
return value problem was fixed by commit a7f40cfe3b7a ("mm: mempolicy:
make mbind() return -EIO when MPOL_MF_STRICT is specified"), but it broke
the VMA walk early if unmovable page is met, it may cause some pages are
not migrated as expected.
The code should conceptually do:
if (MPOL_MF_MOVE|MOVEALL)
scan all vmas
try to migrate the existing pages
return success
else if (MPOL_MF_MOVE* | MPOL_MF_STRICT)
scan all vmas
try to migrate the existing pages
return -EIO if unmovable or migration failed
else /* MPOL_MF_STRICT alone */
break early if meets unmovable and don't call mbind_range() at all
else /* none of those flags */
check the ranges in test_walk, EFAULT without mbind_range() if discontig.
Fixed the behavior.
Link: https://lkml.kernel.org/r/20230920223242.3425775-1-yang@os.amperecomputing.com
Fixes: a7f40cfe3b7a ("mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified")
Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org> [4.9+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When CONFIG_DAMON_VADDR_KUNIT_TEST=y and making CONFIG_DEBUG_KMEMLEAK=y
and CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, the below memory leak is detected.
Since commit 9f86d624292c ("mm/damon/vaddr-test: remove unnecessary
variables"), the damon_destroy_ctx() is removed, but still call
damon_new_target() and damon_new_region(), the damon_region which is
allocated by kmem_cache_alloc() in damon_new_region() and the damon_target
which is allocated by kmalloc in damon_new_target() are not freed. And
the damon_region which is allocated in damon_new_region() in
damon_set_regions() is also not freed.
So use damon_destroy_target to free all the damon_regions and damon_target.
unreferenced object 0xffff888107c9a940 (size 64):
comm "kunit_try_catch", pid 1069, jiffies 4294670592 (age 732.761s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 06 00 00 00 6b 6b 6b 6b ............kkkk
60 c7 9c 07 81 88 ff ff f8 cb 9c 07 81 88 ff ff `...............
backtrace:
[<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
[<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
[<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
[<ffffffff819c82be>] damon_test_apply_three_regions1+0x21e/0x260
[<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
[<ffffffff81237cf6>] kthread+0x2b6/0x380
[<ffffffff81097add>] ret_from_fork+0x2d/0x70
[<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff8881079cc740 (size 56):
comm "kunit_try_catch", pid 1069, jiffies 4294670592 (age 732.761s)
hex dump (first 32 bytes):
05 00 00 00 00 00 00 00 14 00 00 00 00 00 00 00 ................
6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b kkkkkkkk....kkkk
backtrace:
[<ffffffff819bc492>] damon_new_region+0x22/0x1c0
[<ffffffff819c7d91>] damon_do_test_apply_three_regions.constprop.0+0xd1/0x3e0
[<ffffffff819c82be>] damon_test_apply_three_regions1+0x21e/0x260
[<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
[<ffffffff81237cf6>] kthread+0x2b6/0x380
[<ffffffff81097add>] ret_from_fork+0x2d/0x70
[<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff888107c9ac40 (size 64):
comm "kunit_try_catch", pid 1071, jiffies 4294670595 (age 732.843s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 06 00 00 00 6b 6b 6b 6b ............kkkk
a0 cc 9c 07 81 88 ff ff 78 a1 76 07 81 88 ff ff ........x.v.....
backtrace:
[<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
[<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
[<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
[<ffffffff819c851e>] damon_test_apply_three_regions2+0x21e/0x260
[<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
[<ffffffff81237cf6>] kthread+0x2b6/0x380
[<ffffffff81097add>] ret_from_fork+0x2d/0x70
[<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff8881079ccc80 (size 56):
comm "kunit_try_catch", pid 1071, jiffies 4294670595 (age 732.843s)
hex dump (first 32 bytes):
05 00 00 00 00 00 00 00 14 00 00 00 00 00 00 00 ................
6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b kkkkkkkk....kkkk
backtrace:
[<ffffffff819bc492>] damon_new_region+0x22/0x1c0
[<ffffffff819c7d91>] damon_do_test_apply_three_regions.constprop.0+0xd1/0x3e0
[<ffffffff819c851e>] damon_test_apply_three_regions2+0x21e/0x260
[<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
[<ffffffff81237cf6>] kthread+0x2b6/0x380
[<ffffffff81097add>] ret_from_fork+0x2d/0x70
[<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff888107c9af40 (size 64):
comm "kunit_try_catch", pid 1073, jiffies 4294670597 (age 733.011s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 06 00 00 00 6b 6b 6b 6b ............kkkk
20 a2 76 07 81 88 ff ff b8 a6 76 07 81 88 ff ff .v.......v.....
backtrace:
[<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
[<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
[<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
[<ffffffff819c877e>] damon_test_apply_three_regions3+0x21e/0x260
[<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
[<ffffffff81237cf6>] kthread+0x2b6/0x380
[<ffffffff81097add>] ret_from_fork+0x2d/0x70
[<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff88810776a200 (size 56):
comm "kunit_try_catch", pid 1073, jiffies 4294670597 (age 733.011s)
hex dump (first 32 bytes):
05 00 00 00 00 00 00 00 14 00 00 00 00 00 00 00 ................
6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b kkkkkkkk....kkkk
backtrace:
[<ffffffff819bc492>] damon_new_region+0x22/0x1c0
[<ffffffff819c7d91>] damon_do_test_apply_three_regions.constprop.0+0xd1/0x3e0
[<ffffffff819c877e>] damon_test_apply_three_regions3+0x21e/0x260
[<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
[<ffffffff81237cf6>] kthread+0x2b6/0x380
[<ffffffff81097add>] ret_from_fork+0x2d/0x70
[<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff88810776a740 (size 56):
comm "kunit_try_catch", pid 1073, jiffies 4294670597 (age 733.025s)
hex dump (first 32 bytes):
3d 00 00 00 00 00 00 00 3f 00 00 00 00 00 00 00 =.......?.......
6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b kkkkkkkk....kkkk
backtrace:
[<ffffffff819bc492>] damon_new_region+0x22/0x1c0
[<ffffffff819bfcc2>] damon_set_regions+0x4c2/0x8e0
[<ffffffff819c7dbb>] damon_do_test_apply_three_regions.constprop.0+0xfb/0x3e0
[<ffffffff819c877e>] damon_test_apply_three_regions3+0x21e/0x260
[<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
[<ffffffff81237cf6>] kthread+0x2b6/0x380
[<ffffffff81097add>] ret_from_fork+0x2d/0x70
[<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff888108038240 (size 64):
comm "kunit_try_catch", pid 1075, jiffies 4294670600 (age 733.022s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 03 00 00 00 6b 6b 6b 6b ............kkkk
48 ad 76 07 81 88 ff ff 98 ae 76 07 81 88 ff ff H.v.......v.....
backtrace:
[<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
[<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
[<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
[<ffffffff819c898d>] damon_test_apply_three_regions4+0x1cd/0x210
[<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
[<ffffffff81237cf6>] kthread+0x2b6/0x380
[<ffffffff81097add>] ret_from_fork+0x2d/0x70
[<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
unreferenced object 0xffff88810776ad28 (size 56):
comm "kunit_try_catch", pid 1075, jiffies 4294670600 (age 733.022s)
hex dump (first 32 bytes):
05 00 00 00 00 00 00 00 07 00 00 00 00 00 00 00 ................
6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b kkkkkkkk....kkkk
backtrace:
[<ffffffff819bc492>] damon_new_region+0x22/0x1c0
[<ffffffff819bfcc2>] damon_set_regions+0x4c2/0x8e0
[<ffffffff819c7dbb>] damon_do_test_apply_three_regions.constprop.0+0xfb/0x3e0
[<ffffffff819c898d>] damon_test_apply_three_regions4+0x1cd/0x210
[<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
[<ffffffff81237cf6>] kthread+0x2b6/0x380
[<ffffffff81097add>] ret_from_fork+0x2d/0x70
[<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
Link: https://lkml.kernel.org/r/20230925072100.3725620-1-ruanjinjie@huawei.com
Fixes: 9f86d624292c ("mm/damon/vaddr-test: remove unnecessary variables")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This reverts commits 86327e8eb94c ("memcg: drop kmem.limit_in_bytes") and
partially reverts 58056f77502f ("memcg, kmem: further deprecate
kmem.limit_in_bytes") which have incrementally removed support for the
kernel memory accounting hard limit. Unfortunately it has turned out that
there is still userspace depending on the existence of
memory.kmem.limit_in_bytes [1]. The underlying functionality is not
really required but the non-existent file just confuses the userspace
which fails in the result. The patch to fix this on the userspace side
has been submitted but it is hard to predict how it will propagate through
the maze of 3rd party consumers of the software.
Now, reverting alone 86327e8eb94c is not an option because there is
another set of userspace which cannot cope with ENOTSUPP returned when
writing to the file. Therefore we have to go and revisit 58056f77502f as
well. There are two ways to go ahead. Either we give up on the
deprecation and fully revert 58056f77502f as well or we can keep
kmem.limit_in_bytes but make the write a noop and warn about the fact.
This should work for both known breaking workloads which depend on the
existence but do not depend on the hard limit enforcement.
Note to backporters to stable trees. a8c49af3be5f ("memcg: add per-memcg
total kernel memory stat") introduced in 4.18 has added memcg_account_kmem
so the accounting is not done by obj_cgroup_charge_pages directly for v1
anymore. Prior kernels need to add it explicitly (thanks to Johannes for
pointing this out).
[akpm@linux-foundation.org: fix build - remove unused local]
Link: http://lkml.kernel.org/r/20230920081101.GA12096@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net [1]
Link: https://lkml.kernel.org/r/ZRE5VJozPZt9bRPy@dhcp22.suse.cz
Fixes: 86327e8eb94c ("memcg: drop kmem.limit_in_bytes")
Fixes: 58056f77502f ("memcg, kmem: further deprecate kmem.limit_in_bytes")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
While stress-testing zswap a memory corruption was happening when writing
back pages. __frontswap_store used to check for duplicate entries before
attempting to store a page in zswap, this was because if the store fails
the old entry isn't removed from the tree. This change removes duplicate
entries in zswap_store before the actual attempt.
[cerasuolodomenico@gmail.com: add a warning and a comment, per Johannes]
Link: https://lkml.kernel.org/r/20230925130002.1929369-1-cerasuolodomenico@gmail.com
Link: https://lkml.kernel.org/r/20230922172211.1704917-1-cerasuolodomenico@gmail.com
Fixes: 42c06a0e8ebe ("mm: kill frontswap")
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
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
99aa77215ad0 ("selftests/mm: add uffd unit test for UFFDIO_POISON"), which
causes a PTE_MARKER_POISONED swap entry to be set, coutesey of commit
8a13897fb0da ("mm: userfaultfd: support UFFDIO_POISON for hugetlbfs") -
added in v6.5-rc7. Although review shows that there are other call sites
that set PTE_MARKER_UFFD_WP (which also has no PFN), these don't trigger
on arm64 because arm64 doesn't support UFFD WP.
If CONFIG_DEBUG_VM is enabled, we do at least get a BUG(), but otherwise,
it will dereference a bad pointer in page_folio():
static inline struct folio *hugetlb_swap_entry_to_folio(swp_entry_t entry)
{
VM_BUG_ON(!is_migration_entry(entry) && !is_hwpoison_entry(entry));
return page_folio(pfn_to_page(swp_offset_pfn(entry)));
}
Fix
===
The simplest fix would have been to revert the dodgy cleanup commit
18f3962953e4 ("mm: hugetlb: kill set_huge_swap_pte_at()"), but since
things have moved on, this would have required an audit of all the new
set_huge_pte_at() call sites to see if they should be converted to
set_huge_swap_pte_at(). As per the original intent of the change, it
would also leave us open to future bugs when people invariably get it
wrong and call the wrong helper.
So instead, I've added a huge page size parameter to set_huge_pte_at().
This means that the arm64 code has the size in all cases. It's a bigger
change, due to needing to touch the arches that implement the function,
but it is entirely mechanical, so in my view, low risk.
I've compile-tested all touched arches; arm64, parisc, powerpc, riscv,
s390, sparc (and additionally x86_64). I've additionally booted and run
mm selftests against arm64, where I observe the uffd poison test is fixed,
and there are no other regressions.
This patch (of 2):
In order to fix a bug, arm64 needs to be told the size of the huge page
for which the pte is being set in set_huge_pte_at(). Provide for this by
adding an `unsigned long sz` parameter to the function. This follows the
same pattern as huge_pte_clear().
This commit makes the required interface modifications to the core mm as
well as all arches that implement this function (arm64, parisc, powerpc,
riscv, s390, sparc). The actual arm64 bug will be fixed in a separate
commit.
No behavioral changes intended.
Link: https://lkml.kernel.org/r/20230922115804.2043771-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20230922115804.2043771-2-ryan.roberts@arm.com
Fixes: 8a13897fb0da ("mm: userfaultfd: support UFFDIO_POISON for hugetlbfs")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> [powerpc 8xx]
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> [vmalloc change]
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org> [6.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Even though we had successfully mapped the relevant page, we would rarely
return success from filemap_map_folio_range(). That leads to falling back
from the VMA lock path to the mmap_lock path, which is a speed &
scalability issue. Found by inspection.
Link: https://lkml.kernel.org/r/20230920035336.854212-1-willy@infradead.org
Fixes: 617c28ecab22 ("filemap: batch PTE mappings")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab fixes from Vlastimil Babka:
- stable fix to prevent list corruption when destroying caches with
leftover objects (Rafael Aquini)
- fix for a gotcha in kmalloc_size_roundup() when calling it with too
high size, discovered when recently a networking call site had to be
fixed for a different issue (David Laight)
* tag 'slab-fixes-for-6.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
slab: kmalloc_size_roundup() must not return 0 for non-zero size
mm/slab_common: fix slab_caches list corruption after kmem_cache_destroy()
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"13 hotfixes, 10 of which pertain to post-6.5 issues. The other three
are cc:stable"
* tag 'mm-hotfixes-stable-2023-09-23-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
proc: nommu: fix empty /proc/<pid>/maps
filemap: add filemap_map_order0_folio() to handle order0 folio
proc: nommu: /proc/<pid>/maps: release mmap read lock
mm: memcontrol: fix GFP_NOFS recursion in memory.high enforcement
pidfd: prevent a kernel-doc warning
argv_split: fix kernel-doc warnings
scatterlist: add missing function params to kernel-doc
selftests/proc: fixup proc-empty-vm test after KSM changes
revert "scripts/gdb/symbols: add specific ko module load command"
selftests: link libasan statically for tests with -fsanitize=address
task_work: add kerneldoc annotation for 'data' argument
mm: page_alloc: fix CMA and HIGHATOMIC landing on the wrong buddy list
sh: mm: re-add lost __ref to ioremap_prot() to fix modpost warning
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
Pull LoongArch fixes from Huacai Chen:
"Fix lockdep, fix a boot failure, fix some build warnings, fix document
links, and some cleanups"
* tag 'loongarch-fixes-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
docs/zh_CN/LoongArch: Update the links of ABI
docs/LoongArch: Update the links of ABI
LoongArch: Don't inline kasan_mem_to_shadow()/kasan_shadow_to_mem()
kasan: Cleanup the __HAVE_ARCH_SHADOW_MAP usage
LoongArch: Set all reserved memblocks on Node#0 at initialization
LoongArch: Remove dead code in relocate_new_kernel
LoongArch: Use _UL() and _ULL()
LoongArch: Fix some build warnings with W=1
LoongArch: Fix lockdep static memory detection
|
|
This reverts commit d48c3397291690c3576d6c983b0a86ecbc203cac.
Users reported regressions due to enabling multi-grained timestamps
unconditionally. As no clear consensus on a solution has come up and the
discussion has gone back to the drawing board revert the infrastructure
changes for. If it isn't code that's here to stay, make it go away.
Message-ID: <20230920-keine-eile-c9755b5825db@brauner>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
The typical use of kmalloc_size_roundup() is:
ptr = kmalloc(sz = kmalloc_size_roundup(size), ...);
if (!ptr) return -ENOMEM.
This means it is vitally important that the returned value isn't less
than the argument even if the argument is insane.
In particular if kmalloc_slab() fails or the value is above
(MAX_ULONG - PAGE_SIZE) zero is returned and kmalloc() will return
its single zero-length buffer ZERO_SIZE_PTR.
Fix this by returning the input size if the size exceeds
KMALLOC_MAX_SIZE. kmalloc() will then return NULL as the size really is
too big.
kmalloc_slab() should not normally return NULL, unless called too early.
Again, returning zero is not the correct action as it can be in some
usage scenarios stored to a variable and only later cause kmalloc()
return ZERO_SIZE_PTR and subsequent crashes on access. Instead we can
simply stop checking the kmalloc_slab() result completely, as calling
kmalloc_size_roundup() too early would then result in an immediate crash
during boot and the developer noticing an issue in their code.
[vbabka@suse.cz: remove kmalloc_slab() result check, tweak comments and
commit log]
Fixes: 05a940656e1e ("slab: Introduce kmalloc_size_roundup()")
Signed-off-by: David Laight <david.laight@aculab.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
|
|
As Linus suggested, __HAVE_ARCH_XYZ is "stupid" and "having historical
uses of it doesn't make it good". So migrate __HAVE_ARCH_SHADOW_MAP to
separate macros named after the respective functions.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
|
|
Kernel test robot reported regressions for several benchmarks [1].
The regression are related with commit:
de74976eb65151a2f568e477fc2e0032df5b22b4 ("filemap: add filemap_map_folio_range()")
It turned out that function filemap_map_folio_range() brings these
regressions when handle folio with order0.
Add filemap_map_order0_folio() to handle order0 folio. The benefit
come from two perspectives:
- the code size is smaller (around 126 bytes)
- no loop
Testing showed the regressions reported by 0day [1] all are fixed:
commit 9f1f5b60e76d44fa: parent commit of de74976eb65151a2
commit fbdf9263a3d7fdbd: latest mm-unstable commit
commit 7fbfe2003f84686d: this fixing patch
9f1f5b60e76d44fa fbdf9263a3d7fdbd 7fbfe2003f84686d
---------------- --------------------------- ---------------------------
3843810 -21.4% 3020268 +4.6% 4018708 stress-ng.bad-altstack.ops
64061 -21.4% 50336 +4.6% 66977 stress-ng.bad-altstack.ops_per_sec
1709026 -14.4% 1462102 +2.4% 1750757 stress-ng.fork.ops
28483 -14.4% 24368 +2.4% 29179 stress-ng.fork.ops_per_sec
3685088 -53.6% 1710976 +0.5% 3702454 stress-ng.zombie.ops
56732 -65.3% 19667 +0.7% 57107 stress-ng.zombie.ops_per_sec
61874 -12.1% 54416 +0.4% 62136 vm-scalability.median
13527663 -11.7% 11942117 -0.1% 13513946 vm-scalability.throughput
4.066e+09 -11.7% 3.59e+09 -0.1% 4.061e+09 vm-scalability.workload
[1]:
https://lore.kernel.org/oe-lkp/72e017b9-deb6-44fa-91d6-716ee2c39cbc@intel.com/T/#m7d2bba30f75a9cee8eab07e5809abd9b3b206c84
Link: https://lkml.kernel.org/r/20230914134741.1937654-1-fengwei.yin@intel.com
Fixes: de74976eb65151a2f568e477fc2e0032df5b22b4 ("filemap: add filemap_map_folio_range()")
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202309111556.b2aa3d7a-oliver.sang@intel.com
Cc: Feng Tang <feng.tang@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Breno and Josef report a deadlock scenario from cgroup reclaim
re-entering the filesystem:
[ 361.546690] ======================================================
[ 361.559210] WARNING: possible circular locking dependency detected
[ 361.571703] 6.5.0-0_fbk700_debug_rc0_kbuilder_13159_gbf787a128001 #1 Tainted: G S E
[ 361.589704] ------------------------------------------------------
[ 361.602277] find/9315 is trying to acquire lock:
[ 361.611625] ffff88837ba140c0 (&delayed_node->mutex){+.+.}-{4:4}, at: __btrfs_release_delayed_node+0x68/0x4f0
[ 361.631437]
[ 361.631437] but task is already holding lock:
[ 361.643243] ffff8881765b8678 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock+0x1e/0x40
[ 362.904457] mutex_lock_nested+0x1c/0x30
[ 362.912414] __btrfs_release_delayed_node+0x68/0x4f0
[ 362.922460] btrfs_evict_inode+0x301/0x770
[ 362.982726] evict+0x17c/0x380
[ 362.988944] prune_icache_sb+0x100/0x1d0
[ 363.005559] super_cache_scan+0x1f8/0x260
[ 363.013695] do_shrink_slab+0x2a2/0x540
[ 363.021489] shrink_slab_memcg+0x237/0x3d0
[ 363.050606] shrink_slab+0xa7/0x240
[ 363.083382] shrink_node_memcgs+0x262/0x3b0
[ 363.091870] shrink_node+0x1a4/0x720
[ 363.099150] shrink_zones+0x1f6/0x5d0
[ 363.148798] do_try_to_free_pages+0x19b/0x5e0
[ 363.157633] try_to_free_mem_cgroup_pages+0x266/0x370
[ 363.190575] reclaim_high+0x16f/0x1f0
[ 363.208409] mem_cgroup_handle_over_high+0x10b/0x270
[ 363.246678] try_charge_memcg+0xaf2/0xc70
[ 363.304151] charge_memcg+0xf0/0x350
[ 363.320070] __mem_cgroup_charge+0x28/0x40
[ 363.328371] __filemap_add_folio+0x870/0xd50
[ 363.371303] filemap_add_folio+0xdd/0x310
[ 363.399696] __filemap_get_folio+0x2fc/0x7d0
[ 363.419086] pagecache_get_page+0xe/0x30
[ 363.427048] alloc_extent_buffer+0x1cd/0x6a0
[ 363.435704] read_tree_block+0x43/0xc0
[ 363.443316] read_block_for_search+0x361/0x510
[ 363.466690] btrfs_search_slot+0xc8c/0x1520
This is caused by the mem_cgroup_handle_over_high() not respecting the
gfp_mask of the allocation context. We used to only call this function on
resume to userspace, where no locks were held. But c9afe31ec443 ("memcg:
synchronously enforce memory.high for large overcharges") added a call
from the allocation context without considering the gfp.
Link: https://lkml.kernel.org/r/20230914152139.100822-1-hannes@cmpxchg.org
Fixes: c9afe31ec443 ("memcg: synchronously enforce memory.high for large overcharges")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Breno Leitao <leitao@debian.org>
Reported-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org> [5.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Commit 4b23a68f9536 ("mm/page_alloc: protect PCP lists with a spinlock")
bypasses the pcplist on lock contention and returns the page directly to
the buddy list of the page's migratetype.
For pages that don't have their own pcplist, such as CMA and HIGHATOMIC,
the migratetype is temporarily updated such that the page can hitch a ride
on the MOVABLE pcplist. Their true type is later reassessed when flushing
in free_pcppages_bulk(). However, when lock contention is detected after
the type was already overridden, the bypass will then put the page on the
wrong buddy list.
Once on the MOVABLE buddy list, the page becomes eligible for fallbacks
and even stealing. In the case of HIGHATOMIC, otherwise ineligible
allocations can dip into the highatomic reserves. In the case of CMA, the
page can be lost from the CMA region permanently.
Use a separate pcpmigratetype variable for the pcplist override. Use the
original migratetype when going directly to the buddy. This fixes the bug
and should make the intentions more obvious in the code.
Originally sent here to address the HIGHATOMIC case:
https://lore.kernel.org/lkml/20230821183733.106619-4-hannes@cmpxchg.org/
Changelog updated in response to the CMA-specific bug report.
[mgorman@techsingularity.net: updated changelog]
Link: https://lkml.kernel.org/r/20230911181108.GA104295@cmpxchg.org
Fixes: 4b23a68f9536 ("mm/page_alloc: protect PCP lists with a spinlock")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Joe Liu <joe.liu@mediatek.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Commit 408579cd627a ("mm: Update do_vmi_align_munmap() return
semantics") seems to have updated one of the callers of do_vmi_munmap()
incorrectly: it used to check for the error case (which didn't
change: negative means error).
That commit changed the check to the success case (which did change:
before that commit, 0 was success, and 1 was "success and lock
downgraded". After the change, it's always 0 for success, and the lock
will have been released if requested).
This didn't change any actual VM behavior _except_ for memory accounting
when 'VM_ACCOUNT' was set on the vma. Which made the wrong return value
test fairly subtle, since everything continues to work.
Or rather - it continues to work but the "Committed memory" accounting
goes all wonky (Committed_AS value in /proc/meminfo), and depending on
settings that then causes problems much much later as the VM relies on
bogus statistics for its heuristics.
Revert that one line of the change back to the original logic.
Fixes: 408579cd627a ("mm: Update do_vmi_align_munmap() return semantics")
Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Reported-bisected-and-tested-by: Michael Labiuk <michael.labiuk@virtuozzo.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Link: https://lore.kernel.org/all/1694366957@msgid.manchmal.in-ulm.de/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
After the commit in Fixes:, if a module that created a slab cache does not
release all of its allocated objects before destroying the cache (at rmmod
time), we might end up releasing the kmem_cache object without removing it
from the slab_caches list thus corrupting the list as kmem_cache_destroy()
ignores the return value from shutdown_cache(), which in turn never removes
the kmem_cache object from slabs_list in case __kmem_cache_shutdown() fails
to release all of the cache's slabs.
This is easily observable on a kernel built with CONFIG_DEBUG_LIST=y
as after that ill release the system will immediately trip on list_add,
or list_del, assertions similar to the one shown below as soon as another
kmem_cache gets created, or destroyed:
[ 1041.213632] list_del corruption. next->prev should be ffff89f596fb5768, but was 52f1e5016aeee75d. (next=ffff89f595a1b268)
[ 1041.219165] ------------[ cut here ]------------
[ 1041.221517] kernel BUG at lib/list_debug.c:62!
[ 1041.223452] invalid opcode: 0000 [#1] PREEMPT SMP PTI
[ 1041.225408] CPU: 2 PID: 1852 Comm: rmmod Kdump: loaded Tainted: G B W OE 6.5.0 #15
[ 1041.228244] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20230524-3.fc37 05/24/2023
[ 1041.231212] RIP: 0010:__list_del_entry_valid+0xae/0xb0
Another quick way to trigger this issue, in a kernel with CONFIG_SLUB=y,
is to set slub_debug to poison the released objects and then just run
cat /proc/slabinfo after removing the module that leaks slab objects,
in which case the kernel will panic:
[ 50.954843] general protection fault, probably for non-canonical address 0xa56b6b6b6b6b6b8b: 0000 [#1] PREEMPT SMP PTI
[ 50.961545] CPU: 2 PID: 1495 Comm: cat Kdump: loaded Tainted: G B W OE 6.5.0 #15
[ 50.966808] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20230524-3.fc37 05/24/2023
[ 50.972663] RIP: 0010:get_slabinfo+0x42/0xf0
This patch fixes this issue by properly checking shutdown_cache()'s
return value before taking the kmem_cache_release() branch.
Fixes: 0495e337b703 ("mm/slab_common: Deleting kobject in kmem_cache_destroy() without holding slab_mutex/cpu_hotplug_lock")
Signed-off-by: Rafael Aquini <aquini@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
Pull LoongArch updates from Huacai Chen:
- Allow usage of LSX/LASX in the kernel, and use them for
SIMD-optimized RAID5/RAID6 routines
- Add Loongson Binary Translation (LBT) extension support
- Add basic KGDB & KDB support
- Add building with kcov coverage
- Add KFENCE (Kernel Electric-Fence) support
- Add KASAN (Kernel Address Sanitizer) support
- Some bug fixes and other small changes
- Update the default config file
* tag 'loongarch-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (25 commits)
LoongArch: Update Loongson-3 default config file
LoongArch: Add KASAN (Kernel Address Sanitizer) support
LoongArch: Simplify the processing of jumping new kernel for KASLR
kasan: Add (pmd|pud)_init for LoongArch zero_(pud|p4d)_populate process
kasan: Add __HAVE_ARCH_SHADOW_MAP to support arch specific mapping
LoongArch: Add KFENCE (Kernel Electric-Fence) support
LoongArch: Get partial stack information when providing regs parameter
LoongArch: mm: Add page table mapped mode support for virt_to_page()
kfence: Defer the assignment of the local variable addr
LoongArch: Allow building with kcov coverage
LoongArch: Provide kaslr_offset() to get kernel offset
LoongArch: Add basic KGDB & KDB support
LoongArch: Add Loongson Binary Translation (LBT) extension support
raid6: Add LoongArch SIMD recovery implementation
raid6: Add LoongArch SIMD syndrome calculation
LoongArch: Add SIMD-optimized XOR routines
LoongArch: Allow usage of LSX/LASX in the kernel
LoongArch: Define symbol 'fault' as a local label in fpu.S
LoongArch: Adjust {copy, clear}_user exception handler behavior
LoongArch: Use static defined zero page rather than allocated
...
|
|
LoongArch populates pmd/pud with invalid_pmd_table/invalid_pud_table in
pagetable_init, So pmd_init/pud_init(p) is required, define them as __weak
in mm/kasan/init.c, like mm/sparse-vmemmap.c.
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
|
|
MIPS, LoongArch and some other architectures have many holes between
different segments and the valid address space (256T available) is
insufficient to map all these segments to kasan shadow memory with the
common formula provided by kasan core. So we need architecture specific
mapping formulas to ensure different segments are mapped individually,
and only limited space lengths of those specific segments are mapped to
shadow.
Therefore, when the incoming address is converted to a shadow, we need
to add a condition to determine whether it is valid.
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
|
|
The LoongArch architecture is different from other architectures. It
needs to update __kfence_pool during arch_kfence_init_pool().
This patch modifies the assignment location of the local variable addr
in the kfence_init_pool() function to support the case of updating
__kfence_pool in arch_kfence_init_pool().
Acked-by: Marco Elver <elver@google.com>
Signed-off-by: Enze Li <lienze@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"Seven hotfixes. Four are cc:stable and the remainder pertain to issues
which were introduced in the current merge window"
* tag 'mm-hotfixes-stable-2023-09-05-11-51' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
sparc64: add missing initialization of folio in tlb_batch_add()
mm: memory-failure: use rcu lock instead of tasklist_lock when collect_procs()
revert "memfd: improve userspace warnings for missing exec-related flags".
rcu: dump vmalloc memory info safely
mm/vmalloc: add a safer version of find_vm_area() for debug
tools/mm: fix undefined reference to pthread_once
memcontrol: ensure memcg acquired by id is properly set up
|
|
We found a softlock issue in our test, analyzed the logs, and found that
the relevant CPU call trace as follows:
CPU0:
_do_fork
-> copy_process()
-> write_lock_irq(&tasklist_lock) //Disable irq,waiting for
//tasklist_lock
CPU1:
wp_page_copy()
->pte_offset_map_lock()
-> spin_lock(&page->ptl); //Hold page->ptl
-> ptep_clear_flush()
-> flush_tlb_others() ...
-> smp_call_function_many()
-> arch_send_call_function_ipi_mask()
-> csd_lock_wait() //Waiting for other CPUs respond
//IPI
CPU2:
collect_procs_anon()
-> read_lock(&tasklist_lock) //Hold tasklist_lock
->for_each_process(tsk)
-> page_mapped_in_vma()
-> page_vma_mapped_walk()
-> map_pte()
->spin_lock(&page->ptl) //Waiting for page->ptl
We can see that CPU1 waiting for CPU0 respond IPI，CPU0 waiting for CPU2
unlock tasklist_lock, CPU2 waiting for CPU1 unlock page->ptl. As a result,
softlockup is triggered.
For collect_procs_anon(), what we're doing is task list iteration, during
the iteration, with the help of call_rcu(), the task_struct object is freed
only after one or more grace periods elapse. the logic as follows:
release_task()
-> __exit_signal()
-> __unhash_process()
-> list_del_rcu()
-> put_task_struct_rcu_user()
-> call_rcu(&task->rcu, delayed_put_task_struct)
delayed_put_task_struct()
-> put_task_struct()
-> if (refcount_sub_and_test())
__put_task_struct()
-> free_task()
Therefore, under the protection of the rcu lock, we can safely use
get_task_struct() to ensure a safe reference to task_struct during the
iteration.
By removing the use of tasklist_lock in task list iteration, we can break
the softlock chain above.
The same logic can also be applied to:
- collect_procs_file()
- collect_procs_fsdax()
- collect_procs_ksm()
Link: https://lkml.kernel.org/r/20230828022527.241693-1-tongtiangen@huawei.com
Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
