Most of the changes here reduce the amount of locking involved
in logging, due to repeated qemu_log calls, each of which takes
and releases the rcu_read_lock.

This makes more use of qemu_log_lock/unlock around code blocks,
which both keeps the output together in the face of threads and
also plays the rcu_read_lock game only once for the block.

Finally, add a -d tid option to open per-thread logfiles.
This can be extremely helpful in debugging user-only threads.


r~


Richard Henderson (36):
  util/log: Drop manual log buffering
  target/hexagon: Remove qemu_set_log in hexagon_translate_init
  util/log: Pass Error pointer to qemu_set_log
  os-posix: Use qemu_log_enabled
  util/log: Move qemu_log_lock, qemu_log_unlock out of line
  util/log: Treat qemu_log_lock like trylock
  hw/xen: Split out xen_pv_output_msg
  *: Use fprintf between qemu_log_lock/unlock
  util/log: Remove qemu_log_vprintf
  tcg: Pass the locked filepointer to tcg_dump_ops
  exec/translator: Pass the locked filepointer to disas_log hook
  exec/log: Remove log_disas and log_target_disas
  accel/tcg: Use cpu_dump_state between qemu_log_lock/unlock
  target/nios2: Remove log_cpu_state from reset
  util/log: Use qemu_log_lock/unlock in qemu_log
  util/log: Remove qemu_log_flush
  util/log: Drop call to setvbuf
  bsd-user: Expand log_page_dump inline
  linux-user: Expand log_page_dump inline
  tests/unit: Do not reference QemuLogFile directly
  include/exec/log: Do not reference QemuLogFile directly
  include/qemu/log: Move entire implementation out-of-line
  sysemu/os-win32: Test for and use _lock_file/_unlock_file
  util/log: Introduce qemu_set_log_filename_flags
  bsd-user: Use qemu_set_log_filename_flags
  linux-user: Use qemu_set_log_filename_flags
  softmmu: Use qemu_set_log_filename_flags
  util/log: Remove qemu_log_close
  util/log: Rename logfilename to global_filename
  util/log: Rename qemu_logfile to global_file
  util/log: Rename qemu_logfile_mutex to global_mutex
  util/log: Hoist the eval of is_daemonized in qemu_set_log_internal
  util/log: Combine two logfile closes
  util/log: Rename QemuLogFile to RCUCloseFILE
  util/log: Limit RCUCloseFILE to file closing
  util/log: Support per-thread log files

 meson.build                          |  12 +
 include/exec/log.h                   |  52 +----
 include/exec/translator.h            |   2 +-
 include/qemu/log.h                   |  91 +-------
 include/sysemu/os-win32.h            |  16 +-
 accel/tcg/cpu-exec.c                 |  16 +-
 accel/tcg/translate-all.c            | 116 +++++-----
 accel/tcg/translator.c               |  10 +-
 bsd-user/main.c                      |  44 ++--
 cpu.c                                |  10 +-
 hw/net/can/can_sja1000.c             |  24 +-
 hw/xen/xen_pvdev.c                   |  45 ++--
 linux-user/main.c                    |  55 +++--
 linux-user/mmap.c                    |   7 +-
 monitor/misc.c                       |   7 +-
 net/can/can_socketcan.c              |  23 +-
 os-posix.c                           |   2 +-
 qemu-img.c                           |   2 +-
 qemu-io.c                            |   2 +-
 qemu-nbd.c                           |   2 +-
 scsi/qemu-pr-helper.c                |   2 +-
 softmmu/vl.c                         |  21 +-
 storage-daemon/qemu-storage-daemon.c |   2 +-
 target/alpha/translate.c             |   7 +-
 target/arm/translate-a64.c           |   6 +-
 target/arm/translate.c               |   7 +-
 target/avr/translate.c               |   7 +-
 target/cris/translate.c              |   7 +-
 target/hexagon/translate.c           |  13 +-
 target/hppa/translate.c              |  15 +-
 target/i386/tcg/translate.c          |  20 +-
 target/m68k/translate.c              |   7 +-
 target/microblaze/translate.c        |   7 +-
 target/mips/tcg/translate.c          |   7 +-
 target/nios2/cpu.c                   |   5 -
 target/nios2/translate.c             |   7 +-
 target/openrisc/translate.c          |   7 +-
 target/ppc/translate.c               |   7 +-
 target/riscv/translate.c             |  10 +-
 target/rx/translate.c                |   7 +-
 target/s390x/tcg/translate.c         |  11 +-
 target/sh4/translate.c               |   7 +-
 target/sparc/translate.c             |   7 +-
 target/tricore/translate.c           |   7 +-
 target/xtensa/translate.c            |   7 +-
 tcg/tcg.c                            | 176 +++++++-------
 tests/unit/test-logging.c            |  40 ++--
 util/log.c                           | 331 +++++++++++++++++----------
 48 files changed, 669 insertions(+), 626 deletions(-)

-- 
2.25.1

On 3/20/22 10:10, Richard Henderson wrote:
> Most of the changes here reduce the amount of locking involved
> in logging, due to repeated qemu_log calls, each of which takes
> and releases the rcu_read_lock.
> 
> This makes more use of qemu_log_lock/unlock around code blocks,
> which both keeps the output together in the face of threads and
> also plays the rcu_read_lock game only once for the block.
> 
> Finally, add a -d tid option to open per-thread logfiles.
> This can be extremely helpful in debugging user-only threads.

Gah.  I didn't mean to write 'PULL' here, just PATCH.


r~