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  1. 11 Dec, 2023 35 commits
  3. 07 Dec, 2023 5 commits
    • Andrew Morton's avatar
      Merge branch 'master' into mm-hotfixes-stable · 0c92218f
      Andrew Morton authored
      0c92218f
    • Jiexun Wang's avatar
      mm/madvise: add cond_resched() in madvise_cold_or_pageout_pte_range() · b2f557a2
      Jiexun Wang authored 
      I conducted real-time testing and observed that
madvise_cold_or_pageout_pte_range() causes significant latency under
memory pressure, which can be effectively reduced by adding cond_resched()
within the loop.

I tested on the LicheePi 4A board using Cylictest for latency testing and
Ftrace for latency tracing.  The board uses TH1520 processor and has a
memory size of 8GB.  The kernel version is 6.5.0 with the PREEMPT_RT patch
applied.

The script I tested is as follows:

echo wakeup_rt > /sys/kernel/tracing/current_tracer
echo 1 > /sys/kernel/tracing/tracing_on
echo 0 > /sys/kernel/tracing/tracing_max_latency
stress-ng --vm 8 --vm-bytes 2G &
cyclictest --mlockall --smp --priority=99 --distance=0 --duration=30m
echo 0 > /sys/kernel/tracing/tracing_on
cat /sys/kernel/tracing/trace 

The tracing results before modification are as follows:

# tracer: wakeup_rt
#
# wakeup_rt latency trace v1.1.5 on 6.5.0-rt6-r1208-00003-g999d221864bf
# --------------------------------------------------------------------
# latency: 2552 us, #6/6, CPU#3 | (M:preempt_rt VP:0, KP:0, SP:0 HP:0 #P:4)
#    -----------------
#    | task: cyclictest-196 (uid:0 nice:0 policy:1 rt_prio:99)
#    -----------------
#
#                    _--------=> CPU#
#                   / _-------=> irqs-off/BH-disabled
#                  | / _------=> need-resched
#                  || / _-----=> need-resched-lazy
#                  ||| / _----=> hardirq/softirq
#                  |||| / _---=> preempt-depth
#                  ||||| / _--=> preempt-lazy-depth
#                  |||||| / _-=> migrate-disable
#                  ||||||| /     delay
#  cmd     pid     |||||||| time  |   caller
#     \   /        ||||||||  \    |    /
stress-n-206       3dn.h512    2us :      206:120:R   + [003]     196:  0:R cyclictest
stress-n-206       3dn.h512    7us : <stack trace>
 => __ftrace_trace_stack
 => __trace_stack
 => probe_wakeup
 => ttwu_do_activate
 => try_to_wake_up
 => wake_up_process
 => hrtimer_wakeup
 => __hrtimer_run_queues
 => hrtimer_interrupt
 => riscv_timer_interrupt
 => handle_percpu_devid_irq
 => generic_handle_domain_irq
 => riscv_intc_irq
 => handle_riscv_irq
 => do_irq
stress-n-206       3dn.h512    9us#: 0
stress-n-206       3d...3.. 2544us : __schedule
stress-n-206       3d...3.. 2545us :      206:120:R ==> [003]     196:  0:R cyclictest
stress-n-206       3d...3.. 2551us : <stack trace>
 => __ftrace_trace_stack
 => __trace_stack
 => probe_wakeup_sched_switch
 => __schedule
 => preempt_schedule
 => migrate_enable
 => rt_spin_unlock
 => madvise_cold_or_pageout_pte_range
 => walk_pgd_range
 => __walk_page_range
 => walk_page_range
 => madvise_pageout
 => madvise_vma_behavior
 => do_madvise
 => sys_madvise
 => do_trap_ecall_u
 => ret_from_exception

The tracing results after modification are as follows:

# tracer: wakeup_rt
#
# wakeup_rt latency trace v1.1.5 on 6.5.0-rt6-r1208-00004-gca3876fc69a6-dirty
# --------------------------------------------------------------------
# latency: 1689 us, #6/6, CPU#0 | (M:preempt_rt VP:0, KP:0, SP:0 HP:0 #P:4)
#    -----------------
#    | task: cyclictest-217 (uid:0 nice:0 policy:1 rt_prio:99)
#    -----------------
#
#                    _--------=> CPU#
#                   / _-------=> irqs-off/BH-disabled
#                  | / _------=> need-resched
#                  || / _-----=> need-resched-lazy
#                  ||| / _----=> hardirq/softirq
#                  |||| / _---=> preempt-depth
#                  ||||| / _--=> preempt-lazy-depth
#                  |||||| / _-=> migrate-disable
#                  ||||||| /     delay
#  cmd     pid     |||||||| time  |   caller
#     \   /        ||||||||  \    |    /
stress-n-232       0dn.h413    1us+:      232:120:R   + [000]     217:  0:R cyclictest
stress-n-232       0dn.h413   12us : <stack trace>
 => __ftrace_trace_stack
 => __trace_stack
 => probe_wakeup
 => ttwu_do_activate
 => try_to_wake_up
 => wake_up_process
 => hrtimer_wakeup
 => __hrtimer_run_queues
 => hrtimer_interrupt
 => riscv_timer_interrupt
 => handle_percpu_devid_irq
 => generic_handle_domain_irq
 => riscv_intc_irq
 => handle_riscv_irq
 => do_irq
stress-n-232       0dn.h413   19us#: 0
stress-n-232       0d...3.. 1671us : __schedule
stress-n-232       0d...3.. 1676us+:      232:120:R ==> [000]     217:  0:R cyclictest
stress-n-232       0d...3.. 1687us : <stack trace>
 => __ftrace_trace_stack
 => __trace_stack
 => probe_wakeup_sched_switch
 => __schedule
 => preempt_schedule
 => migrate_enable
 => free_unref_page_list
 => release_pages
 => free_pages_and_swap_cache
 => tlb_batch_pages_flush
 => tlb_flush_mmu
 => unmap_page_range
 => unmap_vmas
 => unmap_region
 => do_vmi_align_munmap.constprop.0
 => do_vmi_munmap
 => __vm_munmap
 => sys_munmap
 => do_trap_ecall_u
 => ret_from_exception

After the modification, the cause of maximum latency is no longer
madvise_cold_or_pageout_pte_range(), so this modification can reduce the
latency caused by madvise_cold_or_pageout_pte_range().


Currently the madvise_cold_or_pageout_pte_range() function exhibits
significant latency under memory pressure, which can be effectively
reduced by adding cond_resched() within the loop.

When the batch_count reaches SWAP_CLUSTER_MAX, we reschedule
the task to ensure fairness and avoid long lock holding times.

Link: https://lkml.kernel.org/r/85363861af65fac66c7a98c251906afc0d9c8098.1695291046.git.wangjiexun@tinylab.orgSigned-off-by: default avatarJiexun Wang <wangjiexun@tinylab.org>
Cc: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      b2f557a2
    • Ryusuke Konishi's avatar
      nilfs2: prevent WARNING in nilfs_sufile_set_segment_usage() · 675abf8d
      Ryusuke Konishi authored 
      If nilfs2 reads a disk image with corrupted segment usage metadata, and
its segment usage information is marked as an error for the segment at the
write location, nilfs_sufile_set_segment_usage() can trigger WARN_ONs
during log writing.

Segments newly allocated for writing with nilfs_sufile_alloc() will not
have this error flag set, but this unexpected situation will occur if the
segment indexed by either nilfs->ns_segnum or nilfs->ns_nextnum (active
segment) was marked in error.

Fix this issue by inserting a sanity check to treat it as a file system
corruption.

Since error returns are not allowed during the execution phase where
nilfs_sufile_set_segment_usage() is used, this inserts the sanity check
into nilfs_sufile_mark_dirty() which pre-reads the buffer containing the
segment usage record to be updated and sets it up in a dirty state for
writing.

In addition, nilfs_sufile_set_segment_usage() is also called when
canceling log writing and undoing segment usage update, so in order to
avoid issuing the same kernel warning in that case, in case of
cancellation, avoid checking the error flag in
nilfs_sufile_set_segment_usage().

Link: https://lkml.kernel.org/r/20231205085947.4431-1-konishi.ryusuke@gmail.comSigned-off-by: default avatarRyusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+14e9f834f6ddecece094@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=14e9f834f6ddecece094Tested-by: default avatarRyusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      675abf8d
    • Sidhartha Kumar's avatar
      mm/hugetlb: have CONFIG_HUGETLB_PAGE select CONFIG_XARRAY_MULTI · 4a3ef6be
      Sidhartha Kumar authored 
      After commit a08c7193 "mm/filemap: remove hugetlb special casing in
filemap.c", hugetlb pages are stored in the page cache in base page sized
indexes.  This leads to multi index stores in the xarray which is only
supporting through CONFIG_XARRAY_MULTI.  The other page cache user of
multi index stores ,THP, selects XARRAY_MULTI.  Have CONFIG_HUGETLB_PAGE
follow this behavior as well to avoid the BUG() with a CONFIG_HUGETLB_PAGE
&& !CONFIG_XARRAY_MULTI config.

Link: https://lkml.kernel.org/r/20231204183234.348697-1-sidhartha.kumar@oracle.com
Fixes: a08c7193 ("mm/filemap: remove hugetlb special casing in filemap.c")
Signed-off-by: default avatarSidhartha Kumar <sidhartha.kumar@oracle.com>
Reported-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      4a3ef6be
    • Florian Fainelli's avatar
      scripts/gdb: fix lx-device-list-bus and lx-device-list-class · 801a2b1b
      Florian Fainelli authored 
      After the conversion to bus_to_subsys() and class_to_subsys(), the gdb
scripts listing the system buses and classes respectively was broken, fix
those by returning the subsys_priv pointer and have the various caller
de-reference either the 'bus' or 'class' structure members accordingly.

Link: https://lkml.kernel.org/r/20231130043317.174188-1-florian.fainelli@broadcom.com
Fixes: 7b884b7f ("driver core: class.c: convert to only use class_to_subsys")
Signed-off-by: default avatarFlorian Fainelli <florian.fainelli@broadcom.com>
Tested-by: default avatarKuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      801a2b1b
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