scripts/gdb: update documentation for lx_per_cpu

Commit db08c53fdd542bb7f83b ("scripts/gdb: fix parameter handling in
$lx_per_cpu") changed the parameter handling of lx_per_cpu to use GdbValue
instead of parsing the variable name. Update the documentation to reflect
the new lx_per_cpu usage. Update the hrtimer_bases example to use rb_tree
instead of the timerqueue_head.next pointer removed in commit
511885d7061eda3eb1fa ("lib/timerqueue: Rely on rbtree semantics for next
timer").

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Illia Ostapyshyn <[e-mail]>
Cc: Alex Shi <[e-mail]>
Cc: Brendan Jackman <[e-mail]>
Cc: Dongliang Mu <[e-mail]>
Cc: Florian Rommel <[e-mail]>
Cc: Hu Haowen <[e-mail]>
Cc: Jan Kiszka <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: Kieran Bingham <[e-mail]>
Cc: Yanteng Si <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

Documentation/process/debugging/gdb-kernel-debugging.rst

···
 
 - Make use of the per-cpu function for the current or a specified CPU::
 
-    (gdb) p $lx_per_cpu("runqueues").nr_running
+    (gdb) p $lx_per_cpu(runqueues).nr_running
     $3 = 1
-    (gdb) p $lx_per_cpu("runqueues", 2).nr_running
+    (gdb) p $lx_per_cpu(runqueues, 2).nr_running
     $4 = 0
 
 - Dig into hrtimers using the container_of helper::
 
-    (gdb) set $next = $lx_per_cpu("hrtimer_bases").clock_base[0].active.next
-    (gdb) p *$container_of($next, "struct hrtimer", "node")
+    (gdb) set $leftmost = $lx_per_cpu(hrtimer_bases).clock_base[0].active.rb_root.rb_leftmost
+    (gdb) p *$container_of($leftmost, "struct hrtimer", "node")
     $5 = {
       node = {
         node = {
-          __rb_parent_color = 18446612133355256072,
-          rb_right = 0x0 <irq_stack_union>,
-          rb_left = 0x0 <irq_stack_union>
+          __rb_parent_color = 18446612686384860673,
+          rb_right = 0xffff888231da8b00,
+          rb_left = 0x0
         },
-        expires = {
-          tv64 = 1835268000000
-        }
+        expires = 1228461000000
       },
-      _softexpires = {
-        tv64 = 1835268000000
-      },
-      function = 0xffffffff81078232 <tick_sched_timer>,
-      base = 0xffff88003fd0d6f0,
-      state = 1,
-      start_pid = 0,
-      start_site = 0xffffffff81055c1f <hrtimer_start_range_ns+20>,
-      start_comm = "swapper/2\000\000\000\000\000\000"
+      _softexpires = 1228461000000,
+      function = 0xffffffff8137ab20 <tick_nohz_handler>,
+      base = 0xffff888231d9b4c0,
+      state = 1 '\001',
+      is_rel = 0 '\000',
+      is_soft = 0 '\000',
+      is_hard = 1 '\001'
     }
 
 

Documentation/translations/zh_CN/dev-tools/gdb-kernel-debugging.rst

···
 
 - 对当前或指定的CPU使用per-cpu函数::
 
-    (gdb) p $lx_per_cpu("runqueues").nr_running
+    (gdb) p $lx_per_cpu(runqueues).nr_running
     $3 = 1
-    (gdb) p $lx_per_cpu("runqueues", 2).nr_running
+    (gdb) p $lx_per_cpu(runqueues, 2).nr_running
     $4 = 0
 
 - 使用container_of查看更多hrtimers信息::
 
-    (gdb) set $next = $lx_per_cpu("hrtimer_bases").clock_base[0].active.next
-    (gdb) p *$container_of($next, "struct hrtimer", "node")
+    (gdb) set $leftmost = $lx_per_cpu(hrtimer_bases).clock_base[0].active.rb_root.rb_leftmost
+    (gdb) p *$container_of($leftmost, "struct hrtimer", "node")
     $5 = {
       node = {
         node = {
-          __rb_parent_color = 18446612133355256072,
-          rb_right = 0x0 <irq_stack_union>,
-          rb_left = 0x0 <irq_stack_union>
+          __rb_parent_color = 18446612686384860673,
+          rb_right = 0xffff888231da8b00,
+          rb_left = 0x0
         },
-        expires = {
-          tv64 = 1835268000000
-        }
+        expires = 1228461000000
       },
-      _softexpires = {
-        tv64 = 1835268000000
-      },
-      function = 0xffffffff81078232 <tick_sched_timer>,
-      base = 0xffff88003fd0d6f0,
-      state = 1,
-      start_pid = 0,
-      start_site = 0xffffffff81055c1f <hrtimer_start_range_ns+20>,
-      start_comm = "swapper/2\000\000\000\000\000\000"
+      _softexpires = 1228461000000,
+      function = 0xffffffff8137ab20 <tick_nohz_handler>,
+      base = 0xffff888231d9b4c0,
+      state = 1 '\001',
+      is_rel = 0 '\000',
+      is_soft = 0 '\000',
+      is_hard = 1 '\001'
     }
 
 

Documentation/translations/zh_TW/dev-tools/gdb-kernel-debugging.rst

···
 
 - 對當前或指定的CPU使用per-cpu函數::
 
-    (gdb) p $lx_per_cpu("runqueues").nr_running
+    (gdb) p $lx_per_cpu(runqueues).nr_running
     $3 = 1
-    (gdb) p $lx_per_cpu("runqueues", 2).nr_running
+    (gdb) p $lx_per_cpu(runqueues, 2).nr_running
     $4 = 0
 
 - 使用container_of查看更多hrtimers信息::
 
-    (gdb) set $next = $lx_per_cpu("hrtimer_bases").clock_base[0].active.next
-    (gdb) p *$container_of($next, "struct hrtimer", "node")
+    (gdb) set $leftmost = $lx_per_cpu(hrtimer_bases).clock_base[0].active.rb_root.rb_leftmost
+    (gdb) p *$container_of($leftmost, "struct hrtimer", "node")
     $5 = {
       node = {
         node = {
-          __rb_parent_color = 18446612133355256072,
-          rb_right = 0x0 <irq_stack_union>,
-          rb_left = 0x0 <irq_stack_union>
+          __rb_parent_color = 18446612686384860673,
+          rb_right = 0xffff888231da8b00,
+          rb_left = 0x0
         },
-        expires = {
-          tv64 = 1835268000000
-        }
+        expires = 1228461000000
       },
-      _softexpires = {
-        tv64 = 1835268000000
-      },
-      function = 0xffffffff81078232 <tick_sched_timer>,
-      base = 0xffff88003fd0d6f0,
-      state = 1,
-      start_pid = 0,
-      start_site = 0xffffffff81055c1f <hrtimer_start_range_ns+20>,
-      start_comm = "swapper/2\000\000\000\000\000\000"
+      _softexpires = 1228461000000,
+      function = 0xffffffff8137ab20 <tick_nohz_handler>,
+      base = 0xffff888231d9b4c0,
+      state = 1 '\001',
+      is_rel = 0 '\000',
+      is_soft = 0 '\000',
+      is_hard = 1 '\001'
     }
 
 

scripts/gdb/linux/cpus.py

···
 class PerCpu(gdb.Function):
     """Return per-cpu variable.
 
-$lx_per_cpu("VAR"[, CPU]): Return the per-cpu variable called VAR for the
+$lx_per_cpu(VAR[, CPU]): Return the per-cpu variable called VAR for the
 given CPU number. If CPU is omitted, the CPU of the current context is used.
 Note that VAR has to be quoted as string."""
 
···
 class PerCpuPtr(gdb.Function):
     """Return per-cpu pointer.
 
-$lx_per_cpu_ptr("VAR"[, CPU]): Return the per-cpu pointer called VAR for the
+$lx_per_cpu_ptr(VAR[, CPU]): Return the per-cpu pointer called VAR for the
 given CPU number. If CPU is omitted, the CPU of the current context is used.
 Note that VAR has to be quoted as string."""