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  1. 26 11月, 2015 4 次提交
    • I
      Merge tag 'perf-core-for-mingo-2' of... · a95a49fa
      由 Ingo Molnar 提交于 
      Merge tag 'perf-core-for-mingo-2' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

  - Fix to free temporal Dwarf_Frame correctly in 'perf probe', fixing a
    regression introduced in perf/core that prevented, at least, adding
    an uprobe collecting function parameter values (Masami Hiramatsu)

  - Fix output of %llu for 64 bit values read on 32 bit machines in
    libtraceevent (Steven Rostedt)

Developer visible:

  - Clean CFLAGS and LDFLAGS for fixdep in tools/build (Wang Nan)

  - Don't do a feature check when cleaning tools/lib/bpf (Wang Nan)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      a95a49fa
    • W
      tools lib bpf: Don't do a feature check when cleaning · d8ad6a15
      由 Wang Nan 提交于 
      Before this patch libbpf always do feature check even when cleaning.

For example:

  $ cd kernel/tools/lib/bpf
  $ make

  Auto-detecting system features:
  ...                        libelf: [ on  ]
  ...                           bpf: [ on  ]

    CC       libbpf.o
    CC       bpf.o
    LD       libbpf-in.o
    LINK     libbpf.a
    LINK     libbpf.so
  $ make clean
    CLEAN    libbpf
    CLEAN    core-gen
  $ make clean

  Auto-detecting system features:
  ...                        libelf: [ on  ]
  ...                           bpf: [ on  ]

    CLEAN    libbpf
    CLEAN    core-gen
  $

Although the first 'make clean' doesn't show feature check result, it
still does the check. No output because check result is similar to
FEATURE-DUMP.libbpf.

This patch uses same method as perf to turn off feature checking when
'make clean'.
Reported-and-Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1448372181-151723-3-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      d8ad6a15
    • W
      tools build: Clean CFLAGS and LDFLAGS for fixdep · 5725dd8f
      由 Wang Nan 提交于 
      Sometimes passing variables to tools/build is dangerous. For example, on
my platform there is a gcc problem (gcc 4.8.1):

It passes the stackprotector-all feature check:

  $ gcc -fstack-protector-all -c ./test.c
  $ echo $?
  0

But requires LDFLAGS support if separate compiling and linking:
  $ gcc -fstack-protector-all -c ./test.c
  $ gcc ./test.o
  ./test.o: In function `main':
  test.c:(.text+0xb): undefined reference to `__stack_chk_guard'
  test.c:(.text+0x21): undefined reference to `__stack_chk_guard'
  collect2: error: ld returned 1 exit status
  $ gcc -fstack-protector-all ./test.o
  $ echo $?
  0
  $ gcc ./test.o -lssp
  $ echo $?
  0
  $

In this environment building perf throws an error:

  $ make
    BUILD:   Doing 'make -j24' parallel build
  config/Makefile:344: No libunwind found. Please install libunwind-dev[el] >= 1.1 and/or set LIBUNWIND_DIR
  config/Makefile:403: No libaudit.h found, disables 'trace' tool, please install audit-libs-devel or libaudit-dev
  config/Makefile:418: slang not found, disables TUI support. Please install slang-devel or libslang-dev
  config/Makefile:432: GTK2 not found, disables GTK2 support. Please install gtk2-devel or libgtk2.0-dev
  config/Makefile:564: No bfd.h/libbfd found, please install binutils-dev[el]/zlib-static/libiberty-dev to gain symbol demangling
  config/Makefile:606: No numa.h found, disables 'perf bench numa mem' benchmark, please install numactl-devel/libnuma-devel/libnuma-dev
    CC       fixdep.o
    LD       fixdep-in.o
    LINK     fixdep
  fixdep-in.o: In function `parse_dep_file':
  /kernel/tools/build/fixdep.c:47: undefined reference to `__stack_chk_guard'
  /kernel/tools/build/fixdep.c:117: undefined reference to `__stack_chk_guard'
  fixdep-in.o: In function `main':
  /kernel-hydrogen/tools/build/fixdep.c:156: undefined reference to `__stack_chk_guard'
  /kernel/tools/build/fixdep.c:168: undefined reference to `__stack_chk_guard'
  collect2: error: ld returned 1 exit status
  make[2]: *** [fixdep] Error 1
  make[1]: *** [fixdep] Error 2
  make: *** [all] Error 2

This is because the CFLAGS used in building perf pollutes the CFLAGS
used for fixdep, passing -fstack-protector-all to buiold fixdep which is
obviously not required. Since fixdep is a small host side tool, we
should keep its CFLAGS/LDFLAGS simple and clean.

This patch clears the CFLAGS and LDFLAGS passed when building fixdep, so
such gcc problem won't block the perf build process.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1448372181-151723-2-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      5725dd8f
    • M
      perf probe: Fix to free temporal Dwarf_Frame correctly · 4d3b1626
      由 Masami Hiramatsu 提交于 
      The commit 05c8d802 ("perf probe: Fix to free temporal Dwarf_Frame")
tried to fix the memory leak of Dwarf_Frame, but it released the frame
at wrong point. Since the dwarf_frame_cfa(frame, &pf->fb_ops, &nops) can
return an address inside the frame data structure to pf->fb_ops, we can
not release the frame before using pf->fb_ops.

This reverts the commit and releases the frame afterwards (right before
returning from call_probe_finder) correctly.
Reported-and-Tested-by: NArnaldo Carvalho de Melo <acme@kernel.org>
Reported-by: NMichael Petlan <mpetlan@redhat.com>
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 05c8d802 ("perf probe: Fix to free temporal Dwarf_Frame")
LPU-Reference: 20151125103432.1473.31009.stgit@localhost.localdomain
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      4d3b1626
  3. 24 11月, 2015 9 次提交
  5. 23 11月, 2015 26 次提交
    • A
      perf/x86: Handle multiple umask bits for BDW CYCLE_ACTIVITY.* · b7883a1c
      由 Andi Kleen 提交于 
      The earlier constraint fix for Broadwell CYCLE_ACTIVITY.*
forced umask 8 to counter 2. For this it used UEVENT,
to match the complete umask.

The event list for Broadwell has an additional
STALLS_L1D_PENDIND event that uses umask 8, but also
sets other bits in the umask.  The earlier strict umask match
didn't handle this case.

Add a new UBIT_EVENT constraint macro that only matches
the specified bits in the umask. Then use that macro
to handle CYCLE_ACTIVITY.* on Broadwell.

The documented event also uses cmask, but there's no
need to let the event scheduler know about the cmask,
as the scheduling restriction is only tied to the umask.
Reported-by: NGrant Ayers <ayers@cs.stanford.edu>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1447719667-9998-1-git-send-email-andi@firstfloor.org
[ Filled in the missing email address of Grant Ayers - hopefully I got the right one. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      b7883a1c
    • T
      perf, x86: Stop Intel PT before kdump starts · da06a43d
      由 Takao Indoh 提交于 
      This patch stops Intel PT logging and saves its registers in memory
before kdump is started. This feature is needed to prevent Intel PT from
overwriting its log buffer after panic, and saved registers are needed to
find the last position where Intel PT wrote data.

After the crash dump is captured by kdump, users can retrieve the log buffer
from the vmcore and use it to investigate bad kernel behavior.
Signed-off-by: NTakao Indoh <indou.takao@jp.fujitsu.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin<alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: H.Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/1446614553-6072-3-git-send-email-indou.takao@jp.fujitsu.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      da06a43d
    • T
      perf/x86/intel/pt: Add interface to stop Intel PT logging · 24cc12b1
      由 Takao Indoh 提交于 
      This patch add a function for external components to stop Intel PT.
Basically this function is used when kernel panic occurs. When it is
called, the intel_pt driver disables Intel PT and saves its registers
using pt_event_stop(), which is also used by pmu.stop handler.

This function stops Intel PT on the CPU where it is working, therefore
users of it need to call it for each CPU to stop all logging.
Signed-off-by: NTakao Indoh <indou.takao@jp.fujitsu.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin<alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: H.Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/1446614553-6072-2-git-send-email-indou.takao@jp.fujitsu.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      24cc12b1
    • A
      perf/x86: Add option to disable reading branch flags/cycles · b16a5b52
      由 Andi Kleen 提交于 
      With LBRv5 reading the extra LBR flags like mispredict, TSX, cycles is
not free anymore, as it has moved to a separate MSR.

For callstack mode we don't need any of this information; so we can
avoid the unnecessary MSR read. Add flags to the perf interface where
perf record can request not collecting this information.

Add branch_sample_type flags for CYCLES and FLAGS. It's a bit unusual
for branch_sample_types to be negative (disable), not positive (enable),
but since the legacy ABI reported the flags we need some form of
explicit disabling to avoid breaking the ABI.

After we have the flags the x86 perf code can keep track if any users
need the flags. If noone needs it the information is not collected.

This cuts down the cost of LBR callstack on Skylake significantly.
Profiling a kernel build with LBR call stack the average run time of
the PMI handler drops by 43%.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: http://lkml.kernel.org/r/1445366797-30894-2-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      b16a5b52
    • A
      perf/x86: Optimize stack walk user accesses · 75925e1a
      由 Andi Kleen 提交于 
      Change the perf user stack walking to use the new
__copy_from_user_nmi(), and split each access into word sized transfer
sizes. This allows to inline the complete access and optimize it all
into a single load.

The main advantage is that this avoids the overhead of double page
faults.  When normal copy_from_user() fails it reexecutes the copy to
compute an accurate number of non copied bytes. This leads to
executing the expensive page fault twice.

While walking stacks having a fault at some point is relatively common
(typically when some part of the program isn't compiled with frame
pointers), so this is a large overhead.

With the optimized copies we avoid this problem because they only do
all accesses once. And of course they're much faster too when the
access does not fault because they're just single instructions instead
of complex function calls.

While profiling a kernel build with -g, the patch brings down the
average time of the PMI handler from 966ns to 552ns (-43%).
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1445551641-13379-2-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      75925e1a
    • A
      x86: Add an inlined __copy_from_user_nmi() variant · 10013ebb
      由 Andi Kleen 提交于 
      Add a inlined __ variant of copy_from_user_nmi. The inlined variant allows
the user to:

 - batch the access_ok() check for multiple accesses

 - avoid having a pagefault_disable/enable() on every access if the
   caller already ensures disabled page faults due to its context.

 - get all the optimizations in copy_*_user() for small constant sized
   transfers

It is just a define to __copy_from_user_inatomic().
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1445551641-13379-1-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      10013ebb
    • I
      Merge tag 'perf-core-for-mingo' of... · 8c2accc8
      由 Ingo Molnar 提交于 
      Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

  - Allows BPF scriptlets specify arguments to be fetched using
    DWARF info, using a prologue generated at compile/build time (He Kuang, Wang Nan)

  - Allow attaching BPF scriptlets to module symbols (Wang Nan)

  - Allow attaching BPF scriptlets to userspace code using uprobe (Wang Nan)

  - BPF programs now can specify 'perf probe' tunables via its section name,
    separating key=val values using semicolons (Wang Nan)

Testing some of these new BPF features:

  Use case: get callchains when receiving SSL packets, filter then in the
            kernel, at arbitrary place.

  # cat ssl.bpf.c
  #define SEC(NAME) __attribute__((section(NAME), used))

  struct pt_regs;

  SEC("func=__inet_lookup_established hnum")
  int func(struct pt_regs *ctx, int err, unsigned short port)
  {
          return err == 0 && port == 443;
  }

  char _license[] SEC("license") = "GPL";
  int  _version   SEC("version") = LINUX_VERSION_CODE;
  #
  # perf record -a -g -e ssl.bpf.c
  ^C[ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.787 MB perf.data (3 samples) ]
  # perf script | head -30
  swapper     0 [000] 58783.268118: perf_bpf_probe:func: (ffffffff816a0f60) hnum=0x1bb
	 8a0f61 __inet_lookup_established (/lib/modules/4.3.0+/build/vmlinux)
	 896def ip_rcv_finish (/lib/modules/4.3.0+/build/vmlinux)
	 8976c2 ip_rcv (/lib/modules/4.3.0+/build/vmlinux)
	 855eba __netif_receive_skb_core (/lib/modules/4.3.0+/build/vmlinux)
	 8565d8 __netif_receive_skb (/lib/modules/4.3.0+/build/vmlinux)
	 8572a8 process_backlog (/lib/modules/4.3.0+/build/vmlinux)
	 856b11 net_rx_action (/lib/modules/4.3.0+/build/vmlinux)
	 2a284b __do_softirq (/lib/modules/4.3.0+/build/vmlinux)
	 2a2ba3 irq_exit (/lib/modules/4.3.0+/build/vmlinux)
	 96b7a4 do_IRQ (/lib/modules/4.3.0+/build/vmlinux)
	 969807 ret_from_intr (/lib/modules/4.3.0+/build/vmlinux)
	 2dede5 cpu_startup_entry (/lib/modules/4.3.0+/build/vmlinux)
	 95d5bc rest_init (/lib/modules/4.3.0+/build/vmlinux)
	1163ffa start_kernel ([kernel.vmlinux].init.text)
	11634d7 x86_64_start_reservations ([kernel.vmlinux].init.text)
	1163623 x86_64_start_kernel ([kernel.vmlinux].init.text)

  qemu-system-x86  9178 [003] 58785.792417: perf_bpf_probe:func: (ffffffff816a0f60) hnum=0x1bb
	 8a0f61 __inet_lookup_established (/lib/modules/4.3.0+/build/vmlinux)
	 896def ip_rcv_finish (/lib/modules/4.3.0+/build/vmlinux)
	 8976c2 ip_rcv (/lib/modules/4.3.0+/build/vmlinux)
	 855eba __netif_receive_skb_core (/lib/modules/4.3.0+/build/vmlinux)
	 8565d8 __netif_receive_skb (/lib/modules/4.3.0+/build/vmlinux)
	 856660 netif_receive_skb_internal (/lib/modules/4.3.0+/build/vmlinux)
	 8566ec netif_receive_skb_sk (/lib/modules/4.3.0+/build/vmlinux)
	   430a br_handle_frame_finish ([bridge])
	   48bc br_handle_frame ([bridge])
	 855f44 __netif_receive_skb_core (/lib/modules/4.3.0+/build/vmlinux)
	 8565d8 __netif_receive_skb (/lib/modules/4.3.0+/build/vmlinux)
  #

    Use 'perf probe' various options to list functions, see what variables can
    be collected at any given point, experiment first collecting without a filter,
    then filter, use it together with 'perf trace', 'perf top', with or without
    callchains, if it explodes, please tell us!

  - Introduce a new callchain mode: "folded", that will list per line
    representations of all callchains for a give histogram entry, facilitating
    'perf report' output processing by other tools, such as Brendan Gregg's
    flamegraph tools (Namhyung Kim)

  E.g:

 # perf report | grep -v ^# | head
    18.37%     0.00%  swapper  [kernel.kallsyms]   [k] cpu_startup_entry
                    |
                    ---cpu_startup_entry
                       |
                       |--12.07%--start_secondary
                       |
                        --6.30%--rest_init
                                  start_kernel
                                  x86_64_start_reservations
                                  x86_64_start_kernel
  #

 Becomes, in "folded" mode:

 # perf report -g folded | grep -v ^# | head -5
     18.37%     0.00%  swapper [kernel.kallsyms]   [k] cpu_startup_entry
   12.07% cpu_startup_entry;start_secondary
    6.30% cpu_startup_entry;rest_init;start_kernel;x86_64_start_reservations;x86_64_start_kernel
     16.90%     0.00%  swapper [kernel.kallsyms]   [k] call_cpuidle
   11.23% call_cpuidle;cpu_startup_entry;start_secondary
    5.67% call_cpuidle;cpu_startup_entry;rest_init;start_kernel;x86_64_start_reservations;x86_64_start_kernel
     16.90%     0.00%  swapper [kernel.kallsyms]   [k] cpuidle_enter
   11.23% cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary
    5.67% cpuidle_enter;call_cpuidle;cpu_startup_entry;rest_init;start_kernel;x86_64_start_reservations;x86_64_start_kernel
     15.12%     0.00%  swapper [kernel.kallsyms]   [k] cpuidle_enter_state
  #

   The user can also select one of "count", "period" or "percent" as the first column.

Infrastructure changes:

  - Fix multiple leaks found with Valgrind and a refcount
    debugger (Masami Hiramatsu)

  - Add further 'perf test' entries for BPF and LLVM (Wang Nan)

  - Improve 'perf test' to suport subtests, so that the series of tests
    performed in the LLVM and BPF main tests appear in the default 'perf test'
    output (Wang Nan)

  - Move memdup() from tools/perf to tools/lib/string.c (Arnaldo Carvalho de Melo)

  - Adopt strtobool() from the kernel into tools/lib/ (Wang Nan)

  - Fix selftests_install tools/ Makefile rule (Kevin Hilman)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      8c2accc8
    • P
      treewide: Remove old email address · 90eec103
      由 Peter Zijlstra 提交于 
      There were still a number of references to my old Red Hat email
address in the kernel source. Remove these while keeping the
Red Hat copyright notices intact.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      90eec103
    • A
      perf/x86: Fix LBR call stack save/restore · b28ae956
      由 Andi Kleen 提交于 
      This fixes a bug I added in the following commit:

  90405aa0 ("perf/x86/intel/lbr: Limit LBR accesses to TOS in callstack mode")

The bug could lead to lost LBR call stacks. When restoring the LBR state
we need to use the TOS of the previous context, not the current context.
To do that we need to save/restore the TOS.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: http://lkml.kernel.org/r/1445366797-30894-1-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      b28ae956
    • P
      perf: Update email address in MAINTAINERS · daecbd26
      由 Peter Zijlstra 提交于 
      While still valid, I'm trying to phase out this email address.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      daecbd26
    • S
      perf/core: Robustify the perf_cgroup_from_task() RCU checks · 614e4c4e
      由 Stephane Eranian 提交于 
      This patch reinforces the lockdep checks performed by
perf_cgroup_from_tsk() by passing the perf_event_context
whenever possible. It is okay to not hold the RCU read lock
when we know we hold the ctx->lock. This patch makes sure this
property holds.

In some functions, such as perf_cgroup_sched_in(), we do not
pass the context because we are sure we are holding the RCU
read lock.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: edumazet@google.com
Link: http://lkml.kernel.org/r/1447322404-10920-3-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      614e4c4e
    • S
      perf/core: Fix RCU problem with cgroup context switching code · ddaaf4e2
      由 Stephane Eranian 提交于 
      The RCU checker detected RCU violation in the cgroup switching routines
perf_cgroup_sched_in() and perf_cgroup_sched_out(). We were dereferencing
cgroup from task without holding the RCU lock.

Fix this by holding the RCU read lock. We move the locking from
perf_cgroup_switch() to avoid double locking.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: edumazet@google.com
Link: http://lkml.kernel.org/r/1447322404-10920-2-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      ddaaf4e2
    • L
      Linux 4.4-rc2 · 1ec21837
      由 Linus Torvalds 提交于
      1ec21837
    • L
      Merge branch 'akpm' (patches from Andrew) · 104e2a6f
      由 Linus Torvalds 提交于 
      Merge slub bulk allocator updates from Andrew Morton:
 "This missed the merge window because I was waiting for some repairs to
  come in.  Nothing actually uses the bulk allocator yet and the changes
  to other code paths are pretty small.  And the net guys are waiting
  for this so they can start merging the client code"

More comments from Jesper Dangaard Brouer:
 "The kmem_cache_alloc_bulk() call, in mm/slub.c, were included in
  previous kernel.  The present version contains a bug.  Vladimir
  Davydov noticed it contained a bug, when kernel is compiled with
  CONFIG_MEMCG_KMEM (see commit 03ec0ed5: "slub: fix kmem cgroup
  bug in kmem_cache_alloc_bulk").  Plus the mem cgroup counterpart in
  kmem_cache_free_bulk() were missing (see commit 03374518 "slub:
  add missing kmem cgroup support to kmem_cache_free_bulk").

  I don't consider the fix stable-material because there are no in-tree
  users of the API.

  But with known bugs (for memcg) I cannot start using the API in the
  net-tree"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  slab/slub: adjust kmem_cache_alloc_bulk API
  slub: add missing kmem cgroup support to kmem_cache_free_bulk
  slub: fix kmem cgroup bug in kmem_cache_alloc_bulk
  slub: optimize bulk slowpath free by detached freelist
  slub: support for bulk free with SLUB freelists
      104e2a6f
    • L
      Merge tag 'tty-4.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty · dcfeda9d
      由 Linus Torvalds 提交于 
      Pull tty/serial fixes from Greg KH:
 "Here are a few small tty/serial driver fixes for 4.4-rc2 that resolve
  some reported problems.

  All have been in linux-next, full details are in the shortlog below"

* tag 'tty-4.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: export fsl8250_handle_irq
  serial: 8250_mid: Add missing dependency
  tty: audit: Fix audit source
  serial: etraxfs-uart: Fix crash
  serial: fsl_lpuart: Fix earlycon support
  bcm63xx_uart: Use the device name when registering an interrupt
  tty: Fix direct use of tty buffer work
  tty: Fix tty_send_xchar() lock order inversion
      dcfeda9d
    • L
      Merge tag 'staging-4.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging · 7f217393
      由 Linus Torvalds 提交于 
      Pull staging/IIO fixes from Greg KH:
 "Here are some staging and iio driver fixes for 4.4-rc2.  All of these
  are in response to issues that have been reported and have been in
  linux-next for a while"

* tag 'staging-4.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  Revert "Staging: wilc1000: coreconfigurator: Drop unneeded wrapper functions"
  iio: adc: xilinx: Fix VREFN scale
  iio: si7020: Swap data byte order
  iio: adc: vf610_adc: Fix division by zero error
  iio:ad7793: Fix ad7785 product ID
  iio: ad5064: Fix ad5629/ad5669 shift
  iio:ad5064: Make sure ad5064_i2c_write() returns 0 on success
  iio: lpc32xx_adc: fix warnings caused by enabling unprepared clock
  staging: iio: select IRQ_WORK for IIO_DUMMY_EVGEN
  vf610_adc: Fix internal temperature calculation
      7f217393
    • L
      Merge tag 'usb-4.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb · 6d2d91b3
      由 Linus Torvalds 提交于 
      Pull USB fixes from Greg KH:
 "Here are a number of USB fixes and new device ids for 4.4-rc2.  All
  have been in linux-next and the details are in the shortlog"

* tag 'usb-4.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (28 commits)
  usblp: do not set TASK_INTERRUPTIBLE before lock
  USB: MAINTAINERS: cxacru
  usb: kconfig: fix warning of select USB_OTG
  USB: option: add XS Stick W100-2 from 4G Systems
  xhci: Fix a race in usb2 LPM resume, blocking U3 for usb2 devices
  usb: xhci: fix checking ep busy for CFC
  xhci: Workaround to get Intel xHCI reset working more reliably
  usb: chipidea: imx: fix a possible NULL dereference
  usb: chipidea: usbmisc_imx: fix a possible NULL dereference
  usb: chipidea: otg: gadget module load and unload support
  usb: chipidea: debug: disable usb irq while role switch
  ARM: dts: imx27.dtsi: change the clock information for usb
  usb: chipidea: imx: refine clock operations to adapt for all platforms
  usb: gadget: atmel_usba_udc: Expose correct device speed
  usb: musb: enable usb_dma parameter
  usb: phy: phy-mxs-usb: fix a possible NULL dereference
  usb: dwc3: gadget: let us set lower max_speed
  usb: musb: fix tx fifo flush handling
  usb: gadget: f_loopback: fix the warning during the enumeration
  usb: dwc2: host: Fix remote wakeup when not in DWC2_L2
  ...
      6d2d91b3
    • L
      Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus · 0ec7dc8d
      由 Linus Torvalds 提交于 
      Pull MIPS fixes from Ralf Baechle:

 - Fix a flood of annoying build warnings

 - A number of fixes for Atheros 79xx platforms

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: ath79: Add a machine entry for booting OF machines
  MIPS: ath79: Fix the size of the MISC INTC registers in ar9132.dtsi
  MIPS: ath79: Fix the DDR control initialization on ar71xx and ar934x
  MIPS: Fix flood of warnings about comparsion being always true.
      0ec7dc8d
    • L
      Merge branch 'parisc-4.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux · 94521b2f
      由 Linus Torvalds 提交于 
      Pull parisc update from Helge Deller:
 "This patchset adds Huge Page and HUGETLBFS support for parisc"

Honestly, the hugepage support should have gone through in the merge
window, and is not really an rc-time fix.  But it only touches
arch/parisc, and I cannot find it in myself to care.  If one of the
three parisc users notices a breakage, I will point at Helge and make
rude farting noises.

* 'parisc-4.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Map kernel text and data on huge pages
  parisc: Add Huge Page and HUGETLBFS support
  parisc: Use long branch to do_syscall_trace_exit
  parisc: Increase initial kernel mapping to 32MB on 64bit kernel
  parisc: Initialize the fault vector earlier in the boot process.
  parisc: Add defines for Huge page support
  parisc: Drop unused MADV_xxxK_PAGES flags from asm/mman.h
  parisc: Drop definition of start_thread_som for HP-UX SOM binaries
  parisc: Fix wrong comment regarding first pmd entry flags
      94521b2f
    • L
      Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 727cde6c
      由 Linus Torvalds 提交于 
      Pull perf tool fixes from Thomas Gleixner:
 "A couple of fixes for perf tools:

   - Build system updates

   - Plug a memory leak in an error path of perf probe

   - Tear down probes correctly when adding fails

   - Fixes to the perf symbol handling

   - Fix ordering of event processing in buildid-list

   - Fix per DSO filtering in the histogram browser"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf probe: Clear probe_trace_event when add_probe_trace_event() fails
  perf probe: Fix memory leaking on failure by clearing all probe_trace_events
  perf inject: Also re-pipe lost_samples event
  perf buildid-list: Requires ordered events
  perf symbols: Fix dso lookup by long name and missing buildids
  perf symbols: Allow forcing reading of non-root owned files by root
  perf hists browser: The dso can be obtained from popup_action->ms.map->dso
  perf hists browser: Fix 'd' hotkey action to filter by DSO
  perf symbols: Rebuild rbtree when adjusting symbols for kcore
  tools: Add a "make all" rule
  tools: Actually install tmon in the install rule
      727cde6c
    • L
      Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 069ec229
      由 Linus Torvalds 提交于 
      Pull x86 fixes from Thomas Gleixner:
 "This update contains:

   - MPX updates for handling 32bit processes

   - A fix for a long standing bug in 32bit signal frame handling
     related to FPU/XSAVE state

   - Handle get_xsave_addr() correctly in KVM

   - Fix SMAP check under paravirtualization

   - Add a comment to the static function trace entry to avoid further
     confusion about the difference to dynamic tracing"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Fix SMAP check in PVOPS environments
  x86/ftrace: Add comment on static function tracing
  x86/fpu: Fix get_xsave_addr() behavior under virtualization
  x86/fpu: Fix 32-bit signal frame handling
  x86/mpx: Fix 32-bit address space calculation
  x86/mpx: Do proper get_user() when running 32-bit binaries on 64-bit kernels
      069ec229
    • J
      slab/slub: adjust kmem_cache_alloc_bulk API · 865762a8
      由 Jesper Dangaard Brouer 提交于 
      Adjust kmem_cache_alloc_bulk API before we have any real users.

Adjust API to return type 'int' instead of previously type 'bool'.  This
is done to allow future extension of the bulk alloc API.

A future extension could be to allow SLUB to stop at a page boundary, when
specified by a flag, and then return the number of objects.

The advantage of this approach, would make it easier to make bulk alloc
run without local IRQs disabled.  With an approach of cmpxchg "stealing"
the entire c->freelist or page->freelist.  To avoid overshooting we would
stop processing at a slab-page boundary.  Else we always end up returning
some objects at the cost of another cmpxchg.

To keep compatible with future users of this API linking against an older
kernel when using the new flag, we need to return the number of allocated
objects with this API change.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      865762a8
    • J
      slub: add missing kmem cgroup support to kmem_cache_free_bulk · 03374518
      由 Jesper Dangaard Brouer 提交于 
      Initial implementation missed support for kmem cgroup support in
kmem_cache_free_bulk() call, add this.

If CONFIG_MEMCG_KMEM is not enabled, the compiler should be smart enough
to not add any asm code.

Incoming bulk free objects can belong to different kmem cgroups, and
object free call can happen at a later point outside memcg context.  Thus,
we need to keep the orig kmem_cache, to correctly verify if a memcg object
match against its "root_cache" (s->memcg_params.root_cache).
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      03374518
    • J
      slub: fix kmem cgroup bug in kmem_cache_alloc_bulk · 03ec0ed5
      由 Jesper Dangaard Brouer 提交于 
      The call slab_pre_alloc_hook() interacts with kmemgc and is not allowed to
be called several times inside the bulk alloc for loop, due to the call to
memcg_kmem_get_cache().

This would result in hitting the VM_BUG_ON in __memcg_kmem_get_cache.

As suggested by Vladimir Davydov, change slab_post_alloc_hook() to be able
to handle an array of objects.

A subtle detail is, loop iterator "i" in slab_post_alloc_hook() must have
same type (size_t) as size argument.  This helps the compiler to easier
realize that it can remove the loop, when all debug statements inside loop
evaluates to nothing.  Note, this is only an issue because the kernel is
compiled with GCC option: -fno-strict-overflow

In slab_alloc_node() the compiler inlines and optimizes the invocation of
slab_post_alloc_hook(s, flags, 1, &object) by removing the loop and access
object directly.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Reported-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Suggested-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Reviewed-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      03ec0ed5
    • J
      slub: optimize bulk slowpath free by detached freelist · d0ecd894
      由 Jesper Dangaard Brouer 提交于 
      This change focus on improving the speed of object freeing in the
"slowpath" of kmem_cache_free_bulk.

The calls slab_free (fastpath) and __slab_free (slowpath) have been
extended with support for bulk free, which amortize the overhead of
the (locked) cmpxchg_double.

To use the new bulking feature, we build what I call a detached
freelist.  The detached freelist takes advantage of three properties:

 1) the free function call owns the object that is about to be freed,
    thus writing into this memory is synchronization-free.

 2) many freelist's can co-exist side-by-side in the same slab-page
    each with a separate head pointer.

 3) it is the visibility of the head pointer that needs synchronization.

Given these properties, the brilliant part is that the detached
freelist can be constructed without any need for synchronization.  The
freelist is constructed directly in the page objects, without any
synchronization needed.  The detached freelist is allocated on the
stack of the function call kmem_cache_free_bulk.  Thus, the freelist
head pointer is not visible to other CPUs.

All objects in a SLUB freelist must belong to the same slab-page.
Thus, constructing the detached freelist is about matching objects
that belong to the same slab-page.  The bulk free array is scanned is
a progressive manor with a limited look-ahead facility.

Kmem debug support is handled in call of slab_free().

Notice kmem_cache_free_bulk no longer need to disable IRQs. This
only slowed down single free bulk with approx 3 cycles.

Performance data:
 Benchmarked[1] obj size 256 bytes on CPU i7-4790K @ 4.00GHz

SLUB fastpath single object quick reuse: 47 cycles(tsc) 11.931 ns

To get stable and comparable numbers, the kernel have been booted with
"slab_merge" (this also improve performance for larger bulk sizes).

Performance data, compared against fallback bulking:

bulk -  fallback bulk            - improvement with this patch
   1 -  62 cycles(tsc) 15.662 ns - 49 cycles(tsc) 12.407 ns- improved 21.0%
   2 -  55 cycles(tsc) 13.935 ns - 30 cycles(tsc) 7.506 ns - improved 45.5%
   3 -  53 cycles(tsc) 13.341 ns - 23 cycles(tsc) 5.865 ns - improved 56.6%
   4 -  52 cycles(tsc) 13.081 ns - 20 cycles(tsc) 5.048 ns - improved 61.5%
   8 -  50 cycles(tsc) 12.627 ns - 18 cycles(tsc) 4.659 ns - improved 64.0%
  16 -  49 cycles(tsc) 12.412 ns - 17 cycles(tsc) 4.495 ns - improved 65.3%
  30 -  49 cycles(tsc) 12.484 ns - 18 cycles(tsc) 4.533 ns - improved 63.3%
  32 -  50 cycles(tsc) 12.627 ns - 18 cycles(tsc) 4.707 ns - improved 64.0%
  34 -  96 cycles(tsc) 24.243 ns - 23 cycles(tsc) 5.976 ns - improved 76.0%
  48 -  83 cycles(tsc) 20.818 ns - 21 cycles(tsc) 5.329 ns - improved 74.7%
  64 -  74 cycles(tsc) 18.700 ns - 20 cycles(tsc) 5.127 ns - improved 73.0%
 128 -  90 cycles(tsc) 22.734 ns - 27 cycles(tsc) 6.833 ns - improved 70.0%
 158 -  99 cycles(tsc) 24.776 ns - 30 cycles(tsc) 7.583 ns - improved 69.7%
 250 - 104 cycles(tsc) 26.089 ns - 37 cycles(tsc) 9.280 ns - improved 64.4%

Performance data, compared current in-kernel bulking:

bulk - curr in-kernel  - improvement with this patch
   1 -  46 cycles(tsc) - 49 cycles(tsc) - improved (cycles:-3) -6.5%
   2 -  27 cycles(tsc) - 30 cycles(tsc) - improved (cycles:-3) -11.1%
   3 -  21 cycles(tsc) - 23 cycles(tsc) - improved (cycles:-2) -9.5%
   4 -  18 cycles(tsc) - 20 cycles(tsc) - improved (cycles:-2) -11.1%
   8 -  17 cycles(tsc) - 18 cycles(tsc) - improved (cycles:-1) -5.9%
  16 -  18 cycles(tsc) - 17 cycles(tsc) - improved (cycles: 1)  5.6%
  30 -  18 cycles(tsc) - 18 cycles(tsc) - improved (cycles: 0)  0.0%
  32 -  18 cycles(tsc) - 18 cycles(tsc) - improved (cycles: 0)  0.0%
  34 -  78 cycles(tsc) - 23 cycles(tsc) - improved (cycles:55) 70.5%
  48 -  60 cycles(tsc) - 21 cycles(tsc) - improved (cycles:39) 65.0%
  64 -  49 cycles(tsc) - 20 cycles(tsc) - improved (cycles:29) 59.2%
 128 -  69 cycles(tsc) - 27 cycles(tsc) - improved (cycles:42) 60.9%
 158 -  79 cycles(tsc) - 30 cycles(tsc) - improved (cycles:49) 62.0%
 250 -  86 cycles(tsc) - 37 cycles(tsc) - improved (cycles:49) 57.0%

Performance with normal SLUB merging is significantly slower for
larger bulking.  This is believed to (primarily) be an effect of not
having to share the per-CPU data-structures, as tuning per-CPU size
can achieve similar performance.

bulk - slab_nomerge   -  normal SLUB merge
   1 -  49 cycles(tsc) - 49 cycles(tsc) - merge slower with cycles:0
   2 -  30 cycles(tsc) - 30 cycles(tsc) - merge slower with cycles:0
   3 -  23 cycles(tsc) - 23 cycles(tsc) - merge slower with cycles:0
   4 -  20 cycles(tsc) - 20 cycles(tsc) - merge slower with cycles:0
   8 -  18 cycles(tsc) - 18 cycles(tsc) - merge slower with cycles:0
  16 -  17 cycles(tsc) - 17 cycles(tsc) - merge slower with cycles:0
  30 -  18 cycles(tsc) - 23 cycles(tsc) - merge slower with cycles:5
  32 -  18 cycles(tsc) - 22 cycles(tsc) - merge slower with cycles:4
  34 -  23 cycles(tsc) - 22 cycles(tsc) - merge slower with cycles:-1
  48 -  21 cycles(tsc) - 22 cycles(tsc) - merge slower with cycles:1
  64 -  20 cycles(tsc) - 48 cycles(tsc) - merge slower with cycles:28
 128 -  27 cycles(tsc) - 57 cycles(tsc) - merge slower with cycles:30
 158 -  30 cycles(tsc) - 59 cycles(tsc) - merge slower with cycles:29
 250 -  37 cycles(tsc) - 56 cycles(tsc) - merge slower with cycles:19

Joint work with Alexander Duyck.

[1] https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/mm/slab_bulk_test01.c

[akpm@linux-foundation.org: BUG_ON -> WARN_ON;return]
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NAlexander Duyck <alexander.h.duyck@redhat.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d0ecd894
    • J
      slub: support for bulk free with SLUB freelists · 81084651
      由 Jesper Dangaard Brouer 提交于 
      Make it possible to free a freelist with several objects by adjusting API
of slab_free() and __slab_free() to have head, tail and an objects counter
(cnt).

Tail being NULL indicate single object free of head object.  This allow
compiler inline constant propagation in slab_free() and
slab_free_freelist_hook() to avoid adding any overhead in case of single
object free.

This allows a freelist with several objects (all within the same
slab-page) to be free'ed using a single locked cmpxchg_double in
__slab_free() and with an unlocked cmpxchg_double in slab_free().

Object debugging on the free path is also extended to handle these
freelists.  When CONFIG_SLUB_DEBUG is enabled it will also detect if
objects don't belong to the same slab-page.

These changes are needed for the next patch to bulk free the detached
freelists it introduces and constructs.

Micro benchmarking showed no performance reduction due to this change,
when debugging is turned off (compiled with CONFIG_SLUB_DEBUG).
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NAlexander Duyck <alexander.h.duyck@redhat.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      81084651
  7. 22 11月, 2015 1 次提交