Re: [PATCH] f2fs: fix thread name cannot be fully displayed

[Zhiguo Niu]

Dear Chao,

On Tue, Nov 7, 2023 at 10:53 PM Chao Yu <chao@xxxxxxxxxx> wrote:
>
> On 2023/11/2 9:20, Zhiguo Niu wrote:
> > Because the length of task'name in task_struct can not exceed
> > 16 characters, f2fs some thread'name cannot be fully displayed,
> > including important device number information.
> > If there are more than one partition using the f2fs file system,
> > it is very inconvenient to match partitions and their threads.
> >
> > The following examples show that 4 partitions all use f2fs file system
> > PID: 400    TASK: ffffff80f120c9c0  CPU: 2   COMMAND: "f2fs_discard-25"
> > PID: 392    TASK: ffffff80f6b75880  CPU: 3   COMMAND: "f2fs_discard-25"
> > PID: 400    TASK: ffffff80f120c9c0  CPU: 2   COMMAND: "f2fs_discard-25"
> > PID: 392    TASK: ffffff80f6b75880  CPU: 3   COMMAND: "f2fs_discard-25"
> > PID: 510    TASK: ffffff80dd62c9c0  CPU: 0   COMMAND: "f2fs_ckpt-254:4"
> > PID: 255    TASK: ffffff80f2268000  CPU: 3   COMMAND: "f2fs_ckpt-259:4"
> > PID: 398    TASK: ffffff80f120ac40  CPU: 2   COMMAND: "f2fs_ckpt-259:4"
> > PID: 390    TASK: ffffff80f6b76740  CPU: 3   COMMAND: "f2fs_ckpt-259:4"
> > PID: 511    TASK: ffffff80dd629d80  CPU: 3   COMMAND: "f2fs_flush-254:"
> > PID: 399    TASK: ffffff80f120bb00  CPU: 2   COMMAND: "f2fs_flush-259:"
> > PID: 391    TASK: ffffff80f6b70000  CPU: 3   COMMAND: "f2fs_flush-259:"
> > PID: 256    TASK: ffffff80f226d880  CPU: 6   COMMAND: "f2fs_flush-259:"
> >
> > We can use the name format such as f2fs_gc-xxx, as saw in device:
> > PID: 260    TASK: ffffff80f8c2e740  CPU: 3   COMMAND: "f2fs_gc-259:44"
> > PID: 420    TASK: ffffff80f6505880  CPU: 2   COMMAND: "f2fs_gc-259:41"
> > PID: 393    TASK: ffffff80f6b72c40  CPU: 1   COMMAND: "f2fs_gc-259:40
> > PID: 513    TASK: ffffff80dd62e740  CPU: 1   COMMAND: "f2fs_gc-254:40"
>
> Can you please check comments in below link?
>
> https://lore.kernel.org/linux-f2fs-devel/8eaad9d0-1d59-3ecb-bab4-904ed22385f4@xxxxxxxxxx/
>
Thanks for your share and I got it.
> Thanks,
>
> >
> > Signed-off-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
> > ---
> >   fs/f2fs/checkpoint.c | 2 +-
> >   fs/f2fs/segment.c    | 4 ++--
> >   2 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > index b0597a5..f6a5424 100644
> > --- a/fs/f2fs/checkpoint.c
> > +++ b/fs/f2fs/checkpoint.c
> > @@ -1893,7 +1893,7 @@ int f2fs_start_ckpt_thread(struct f2fs_sb_info *sbi)
> >               return 0;
> >
> >       cprc->f2fs_issue_ckpt = kthread_run(issue_checkpoint_thread, sbi,
> > -                     "f2fs_ckpt-%u:%u", MAJOR(dev), MINOR(dev));
> > +                     "f2fs_cp-%u:%u", MAJOR(dev), MINOR(dev));
> >       if (IS_ERR(cprc->f2fs_issue_ckpt)) {
> >               int err = PTR_ERR(cprc->f2fs_issue_ckpt);
> >
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index d05b416..b290713 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -677,7 +677,7 @@ int f2fs_create_flush_cmd_control(struct f2fs_sb_info *sbi)
> >
> >   init_thread:
> >       fcc->f2fs_issue_flush = kthread_run(issue_flush_thread, sbi,
> > -                             "f2fs_flush-%u:%u", MAJOR(dev), MINOR(dev));
> > +                             "f2fs_fh-%u:%u", MAJOR(dev), MINOR(dev));
> >       if (IS_ERR(fcc->f2fs_issue_flush)) {
> >               int err = PTR_ERR(fcc->f2fs_issue_flush);
> >
> > @@ -2248,7 +2248,7 @@ int f2fs_start_discard_thread(struct f2fs_sb_info *sbi)
> >               return 0;
> >
> >       dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
> > -                             "f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
> > +                             "f2fs_dc-%u:%u", MAJOR(dev), MINOR(dev));
> >       if (IS_ERR(dcc->f2fs_issue_discard)) {
> >               err = PTR_ERR(dcc->f2fs_issue_discard);
> >               dcc->f2fs_issue_discard = NULL;