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clean up codes #9

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thehajime opened this issue Nov 11, 2014 · 2 comments
Open

clean up codes #9

thehajime opened this issue Nov 11, 2014 · 2 comments
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@thehajime
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  • mixture of user and kernel space headers
  • duplicated prototype declaration across files
  • coding style => should be linux net-next
  • Werror compile
@thehajime thehajime added the bug label Nov 11, 2014
@thehajime thehajime assigned thehajime and upa and unassigned thehajime and upa Nov 18, 2014
@thehajime thehajime added this to the asap_141124 milestone Nov 18, 2014
@thehajime
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checkpatch.pl and uncrustify are used and updated with 682d492.

more clean ups are needed

  • mixture of user and kernel space headers
  • duplicated prototype declaration across files
  • Werror compile

@thehajime
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78b3220 address the following issue.

  • mixture of user and kernel space headers
  • duplicated prototype declaration across files

the rest cleanup would be;

  • Werror compile

thehajime pushed a commit that referenced this issue Apr 8, 2015
Andrew Lunn says:

====================
DSA Mavell drivers refactoring and cleanup

v1->v2:
 * Add missing signed-of-by: For patches authored by Guenter Roeck.
 * Add Reviewed by from Guenter Roack to patch #5.

This is a collection of patches again net-next from today containing
refactoring and consolidate of code, cleanups and using #define's to
replace register numbers.

Patch #1 Swaps the 6131 driver to use the consolidated setup code.

Patch #2 Moves the Switch IDs used during probe into a central
         location.  We need these later so that we can differentiate
         the different features the devices have.

Patch #3 Makes the 6131 driver set the number of ports in the private
         state structure. It then uses this, rather than hard coded
         maximum number of ports.

Patch #4 Similar to Patch #3, but for the 6123_61_65 driver.

Patch #5 Similar to Patch #3, and #4, but for all the remaining
         drivers.  This greatly increases the similarity of the code
         between drivers, allow further patches to consolidate the
         duplicated code.

Patch #6 Consolidate the switch reset code, which has two minor
         variants. Removes around 35 lines per driver.

Patch #7 Moves phy page access functions out of the 6352 driver into
         the shared code. Currently only the 6352 driver uses this,
         but it is likely other devices will come along wanting this
         functionality.

Patch #8 Consolidates the code used to access phy registers. Removes
         around 40 lines of code per driver.

Patch #9 Fixes missing mutex locking in the EEE code, and refactors
         the code a bit to make it more understandable with respect to
         locks.

Patch #10 Consolidates reading statistics. This is very similar code
          for all devices, but the number of available statistics
          differ, which can be determined from the product ID. Removes
	  around 65 lines per driver.

Patch #11 Add #defines for registers, and bits within the
          registers. For the moment, this is limited to the shared
          code. The individual drivers will be converted once the
          remaining duplicated code is consolidated

Patch #12 Fix broken statistic counters on the 6172. The 6352 family
          requires the port number is poked into a different set of
          bits in the register compared to other devices.

Many thanks to Guenter Roeck for repeatedly reviewing the patches and
testing them on his hardware.
====================

Signed-off-by: David S. Miller <[email protected]>
thehajime pushed a commit that referenced this issue May 12, 2015
Andrew Lunn says:

====================
More Marvell DSA refactring and fixup

This patch setup continues the refactoring and cleanup of the Marvell
DSA drivers.

Patch #1 Centralizes the duplicated parts of port setup and global
setup into the shared mv88e6xxx.

Patch #2 Centralizes looping over the ports setting them up

Patch #3 Uses mnemonics for the remaining register access in the
drivers.

Patch #4 The 6172 is actually a member of the 6352 family. This moves
the probe code into the correct driver.

Patch #5 Adds more members of the 6171 family to the 6171 driver. The
new devices are untested.

Patch #6 The 6185 is a member of the 6131 family. Add it to the probe
code of the 6131 driver.

Patch #7 and Patch #8 Simply the mutex's in mv88e6xxx.c. The SMI bus
is the bottleneck, not the granularity of the mutex's so simply the
code down to a single mutex.

Patch #8 Fixes a false positive lockdep splat, due to nested uses of
MDIO busses.

Patch #9 Fixes another false positive lockdep splat with the transmit
queue because of stacked Ethernet devices.
====================

Signed-off-by: David S. Miller <[email protected]>
thehajime pushed a commit that referenced this issue Jun 11, 2015
Since tracepoints use RCU for protection, they must not be called on
offline cpus.  trace_kmem_cache_free can be called on an offline cpu in
this scenario caught by LOCKDEP:

    ===============================
    [ INFO: suspicious RCU usage. ]
    4.1.0-rc1+ #9 Not tainted
    -------------------------------
    include/trace/events/kmem.h:148 suspicious rcu_dereference_check() usage!

    other info that might help us debug this:

    RCU used illegally from offline CPU!
    rcu_scheduler_active = 1, debug_locks = 1
    no locks held by swapper/1/0.

    stack backtrace:
    CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.1.0-rc1+ #9
    Call Trace:
      .dump_stack+0x98/0xd4 (unreliable)
      .lockdep_rcu_suspicious+0x108/0x170
      .kmem_cache_free+0x344/0x4b0
      .__mmdrop+0x4c/0x160
      .idle_task_exit+0xf0/0x100
      .pnv_smp_cpu_kill_self+0x58/0x2c0
      .cpu_die+0x34/0x50
      .arch_cpu_idle_dead+0x20/0x40
      .cpu_startup_entry+0x708/0x7a0
      .start_secondary+0x36c/0x3a0
      start_secondary_prolog+0x10/0x14

Fix this by converting kmem_cache_free trace point into
TRACE_EVENT_CONDITION where condition is cpu_online(smp_processor_id())

Signed-off-by: Shreyas B. Prabhu <[email protected]>
Reported-by: Aneesh Kumar K.V <[email protected]>
Reviewed-by: Preeti U Murthy <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
thehajime pushed a commit that referenced this issue Jun 11, 2015
Since tracepoints use RCU for protection, they must not be called on
offline cpus.  trace_mm_page_free can be called on an offline cpu in this
scenario caught by LOCKDEP:

     ===============================
     [ INFO: suspicious RCU usage. ]
     4.1.0-rc1+ #9 Not tainted
     -------------------------------
     include/trace/events/kmem.h:170 suspicious rcu_dereference_check() usage!

    other info that might help us debug this:

    RCU used illegally from offline CPU!
    rcu_scheduler_active = 1, debug_locks = 1
     no locks held by swapper/1/0.

    stack backtrace:
     CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.1.0-rc1+ #9
     Call Trace:
       .dump_stack+0x98/0xd4 (unreliable)
       .lockdep_rcu_suspicious+0x108/0x170
       .free_pages_prepare+0x494/0x680
       .free_hot_cold_page+0x50/0x280
       .destroy_context+0x90/0xd0
       .__mmdrop+0x58/0x160
       .idle_task_exit+0xf0/0x100
       .pnv_smp_cpu_kill_self+0x58/0x2c0
       .cpu_die+0x34/0x50
       .arch_cpu_idle_dead+0x20/0x40
       .cpu_startup_entry+0x708/0x7a0
       .start_secondary+0x36c/0x3a0
       start_secondary_prolog+0x10/0x14

Fix this by converting mm_page_free trace point into TRACE_EVENT_CONDITION
where condition is cpu_online(smp_processor_id())

Signed-off-by: Shreyas B. Prabhu <[email protected]>
Reviewed-by: Preeti U Murthy <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
thehajime pushed a commit that referenced this issue Jun 11, 2015
Since tracepoints use RCU for protection, they must not be called on
offline cpus.  trace_mm_page_pcpu_drain can be called on an offline cpu
in this scenario caught by LOCKDEP:

     ===============================
     [ INFO: suspicious RCU usage. ]
     4.1.0-rc1+ #9 Not tainted
     -------------------------------
     include/trace/events/kmem.h:265 suspicious rcu_dereference_check() usage!

    other info that might help us debug this:

    RCU used illegally from offline CPU!
    rcu_scheduler_active = 1, debug_locks = 1
     1 lock held by swapper/5/0:
      #0:  (&(&zone->lock)->rlock){..-...}, at: [<c0000000002073b0>] .free_pcppages_bulk+0x70/0x920

    stack backtrace:
     CPU: 5 PID: 0 Comm: swapper/5 Not tainted 4.1.0-rc1+ #9
     Call Trace:
       .dump_stack+0x98/0xd4 (unreliable)
       .lockdep_rcu_suspicious+0x108/0x170
       .free_pcppages_bulk+0x60c/0x920
       .free_hot_cold_page+0x208/0x280
       .destroy_context+0x90/0xd0
       .__mmdrop+0x58/0x160
       .idle_task_exit+0xf0/0x100
       .pnv_smp_cpu_kill_self+0x58/0x2c0
       .cpu_die+0x34/0x50
       .arch_cpu_idle_dead+0x20/0x40
       .cpu_startup_entry+0x708/0x7a0
       .start_secondary+0x36c/0x3a0
       start_secondary_prolog+0x10/0x14

Fix this by converting mm_page_pcpu_drain trace point into
TRACE_EVENT_CONDITION where condition is cpu_online(smp_processor_id())

Signed-off-by: Shreyas B. Prabhu <[email protected]>
Reviewed-by: Preeti U Murthy <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
thehajime pushed a commit that referenced this issue Aug 14, 2015
Alex reported the following crash when using fq_codel
with htb:

  crash> bt
  PID: 630839  TASK: ffff8823c990d280  CPU: 14  COMMAND: "tc"
   [... snip ...]
   #8 [ffff8820ceec17a0] page_fault at ffffffff8160a8c2
      [exception RIP: htb_qlen_notify+24]
      RIP: ffffffffa0841718  RSP: ffff8820ceec1858  RFLAGS: 00010282
      RAX: 0000000000000000  RBX: 0000000000000000  RCX: ffff88241747b400
      RDX: ffff88241747b408  RSI: 0000000000000000  RDI: ffff8811fb27d000
      RBP: ffff8820ceec1868   R8: ffff88120cdeff24   R9: ffff88120cdeff30
      R10: 0000000000000bd4  R11: ffffffffa0840919  R12: ffffffffa0843340
      R13: 0000000000000000  R14: 0000000000000001  R15: ffff8808dae5c2e8
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
   #9 [...] qdisc_tree_decrease_qlen at ffffffff81565375
  #10 [...] fq_codel_dequeue at ffffffffa084e0a0 [sch_fq_codel]
  #11 [...] fq_codel_reset at ffffffffa084e2f8 [sch_fq_codel]
  #12 [...] qdisc_destroy at ffffffff81560d2d
  #13 [...] htb_destroy_class at ffffffffa08408f8 [sch_htb]
  #14 [...] htb_put at ffffffffa084095c [sch_htb]
  #15 [...] tc_ctl_tclass at ffffffff815645a3
  #16 [...] rtnetlink_rcv_msg at ffffffff81552cb0
  [... snip ...]

As Jamal pointed out, there is actually no need to call dequeue
to purge the queued skb's in reset, data structures can be just
reset explicitly. Therefore, we reset everything except config's
and stats, so that we would have a fresh start after device flipping.

Fixes: 4b549a2 ("fq_codel: Fair Queue Codel AQM")
Reported-by: Alex Gartrell <[email protected]>
Cc: Alex Gartrell <[email protected]>
Cc: Jamal Hadi Salim <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
[[email protected]: added codel_vars_init() and qdisc_qstats_backlog_dec()]
Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
thehajime pushed a commit that referenced this issue Aug 14, 2015
Nikolay has reported a hang when a memcg reclaim got stuck with the
following backtrace:

PID: 18308  TASK: ffff883d7c9b0a30  CPU: 1   COMMAND: "rsync"
  #0 __schedule at ffffffff815ab152
  #1 schedule at ffffffff815ab76e
  #2 schedule_timeout at ffffffff815ae5e5
  #3 io_schedule_timeout at ffffffff815aad6a
  #4 bit_wait_io at ffffffff815abfc6
  #5 __wait_on_bit at ffffffff815abda5
  #6 wait_on_page_bit at ffffffff8111fd4f
  #7 shrink_page_list at ffffffff81135445
  #8 shrink_inactive_list at ffffffff81135845
  #9 shrink_lruvec at ffffffff81135ead
 #10 shrink_zone at ffffffff811360c3
 #11 shrink_zones at ffffffff81136eff
 #12 do_try_to_free_pages at ffffffff8113712f
 #13 try_to_free_mem_cgroup_pages at ffffffff811372be
 #14 try_charge at ffffffff81189423
 #15 mem_cgroup_try_charge at ffffffff8118c6f5
 #16 __add_to_page_cache_locked at ffffffff8112137d
 #17 add_to_page_cache_lru at ffffffff81121618
 #18 pagecache_get_page at ffffffff8112170b
 #19 grow_dev_page at ffffffff811c8297
 #20 __getblk_slow at ffffffff811c91d6
 #21 __getblk_gfp at ffffffff811c92c1
 #22 ext4_ext_grow_indepth at ffffffff8124565c
 #23 ext4_ext_create_new_leaf at ffffffff81246ca8
 #24 ext4_ext_insert_extent at ffffffff81246f09
 #25 ext4_ext_map_blocks at ffffffff8124a848
 #26 ext4_map_blocks at ffffffff8121a5b7
 #27 mpage_map_one_extent at ffffffff8121b1fa
 #28 mpage_map_and_submit_extent at ffffffff8121f07b
 #29 ext4_writepages at ffffffff8121f6d5
 #30 do_writepages at ffffffff8112c490
 #31 __filemap_fdatawrite_range at ffffffff81120199
 #32 filemap_flush at ffffffff8112041c
 #33 ext4_alloc_da_blocks at ffffffff81219da1
 #34 ext4_rename at ffffffff81229b91
 #35 ext4_rename2 at ffffffff81229e32
 #36 vfs_rename at ffffffff811a08a5
 #37 SYSC_renameat2 at ffffffff811a3ffc
 #38 sys_renameat2 at ffffffff811a408e
 #39 sys_rename at ffffffff8119e51e
 #40 system_call_fastpath at ffffffff815afa89

Dave Chinner has properly pointed out that this is a deadlock in the
reclaim code because ext4 doesn't submit pages which are marked by
PG_writeback right away.

The heuristic was introduced by commit e62e384 ("memcg: prevent OOM
with too many dirty pages") and it was applied only when may_enter_fs
was specified.  The code has been changed by c3b94f4 ("memcg:
further prevent OOM with too many dirty pages") which has removed the
__GFP_FS restriction with a reasoning that we do not get into the fs
code.  But this is not sufficient apparently because the fs doesn't
necessarily submit pages marked PG_writeback for IO right away.

ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily
submit the bio.  Instead it tries to map more pages into the bio and
mpage_map_one_extent might trigger memcg charge which might end up
waiting on a page which is marked PG_writeback but hasn't been submitted
yet so we would end up waiting for something that never finishes.

Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2)
before we go to wait on the writeback.  The page fault path, which is
the only path that triggers memcg oom killer since 3.12, shouldn't
require GFP_NOFS and so we shouldn't reintroduce the premature OOM
killer issue which was originally addressed by the heuristic.

As per David Chinner the xfs is doing similar thing since 2.6.15 already
so ext4 is not the only affected filesystem.  Moreover he notes:

: For example: IO completion might require unwritten extent conversion
: which executes filesystem transactions and GFP_NOFS allocations. The
: writeback flag on the pages can not be cleared until unwritten
: extent conversion completes. Hence memory reclaim cannot wait on
: page writeback to complete in GFP_NOFS context because it is not
: safe to do so, memcg reclaim or otherwise.

Cc: [email protected] # 3.9+
[[email protected]: corrected the control flow]
Fixes: c3b94f4 ("memcg: further prevent OOM with too many dirty pages")
Reported-by: Nikolay Borisov <[email protected]>
Signed-off-by: Michal Hocko <[email protected]>
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
thehajime pushed a commit that referenced this issue Aug 14, 2015
It turns out that a PV domU also requires the "Xen PV" APIC
driver. Otherwise, the flat driver is used and we get stuck in busy
loops that never exit, such as in this stack trace:

(gdb) target remote localhost:9999
Remote debugging using localhost:9999
__xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
56              while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
(gdb) bt
 #0  __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
 #1  __default_send_IPI_shortcut (shortcut=<optimized out>,
dest=<optimized out>, vector=<optimized out>) at
./arch/x86/include/asm/ipi.h:75
 #2  apic_send_IPI_self (vector=246) at arch/x86/kernel/apic/probe_64.c:54
 #3  0xffffffff81011336 in arch_irq_work_raise () at
arch/x86/kernel/irq_work.c:47
 #4  0xffffffff8114990c in irq_work_queue (work=0xffff88000fc0e400) at
kernel/irq_work.c:100
 #5  0xffffffff8110c29d in wake_up_klogd () at kernel/printk/printk.c:2633
 #6  0xffffffff8110ca60 in vprintk_emit (facility=0, level=<optimized
out>, dict=0x0 <irq_stack_union>, dictlen=<optimized out>,
fmt=<optimized out>, args=<optimized out>)
    at kernel/printk/printk.c:1778
 #7  0xffffffff816010c8 in printk (fmt=<optimized out>) at
kernel/printk/printk.c:1868
 #8  0xffffffffc00013ea in ?? ()
 #9  0x0000000000000000 in ?? ()

Mailing-list-thread: https://lkml.org/lkml/2015/8/4/755
Signed-off-by: Jason A. Donenfeld <[email protected]>
Cc: <[email protected]>
Signed-off-by: David Vrabel <[email protected]>
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