Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1216024

Re: [PATCH] task_work: remove fifo ordering guarantee

Show all headers | View raw

> On Aug 30, 2015, at 01:08, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> 
> On Sat, Aug 29, 2015 at 7:11 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
>> 
>> If this needs to be kept, maybe then add following, to make sure
>> we flush the list at most every BITS_PER_LONG files
> 
> Hmm.
> 
> I'm wondering if we should just make close_files() (or maybe even
> filp_close()) use a synchronous fput().
> 
> Iirc, the reason we delay fput() is that we had some nasty issues for
> the generic fput case. It was called from interrupt context by the aio
> code, and just in general there's a lot of nasty cases that can cause
> the final fput to happen (so there are lockdep issues with the mmap
> locks because the last fput being from munmap etc).
> 
> Maybe I forget some detail - it's been several years by now - but I
> think we could make the regular "close()" and "exit()" cases just use
> the synchronous fput (it's called "__fput_sync()" and currently
> explicitly limited to just kernel threads).
> 
> Al?
> 
> Because it feels all kinds of stupid to add things to the task-work
> queue just to then remove it almost immediately again. And
> close_files() is also called from various contexts. but the whole "put
> the final 'files_struct' case is certainly not at all as special as
> the 'put the final file'.
> 
>                    Linus
> —
why not provide API like:
fput()
fput_nosync() ?

because synchronous version are reasonable and safe in most time,
let the user to select which version to use is more feasible, no matter if it is kthread or not.

Thanks


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH] task_work: remove fifo ordering guarantee Eric Dumazet <eric.dumazet@gmail.com> - 2015-08-29 04:50 +0200
  Re: [PATCH] task_work: remove fifo ordering guarantee Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-29 05:20 +0200
    Re: [PATCH] task_work: remove fifo ordering guarantee Ingo Molnar <mingo@kernel.org> - 2015-08-29 11:30 +0200
      Re: [PATCH] task_work: remove fifo ordering guarantee Oleg Nesterov <oleg@redhat.com> - 2015-08-29 15:00 +0200
        Re: [PATCH] task_work: remove fifo ordering guarantee Ingo Molnar <mingo@kernel.org> - 2015-08-31 08:10 +0200
          Re: [PATCH] task_work: remove fifo ordering guarantee Oleg Nesterov <oleg@redhat.com> - 2015-08-31 15:00 +0200
  Re: [PATCH] task_work: remove fifo ordering guarantee Oleg Nesterov <oleg@redhat.com> - 2015-08-29 15:00 +0200
    Re: [PATCH] task_work: remove fifo ordering guarantee Eric Dumazet <eric.dumazet@gmail.com> - 2015-08-29 16:00 +0200
      Re: [PATCH] task_work: remove fifo ordering guarantee Eric Dumazet <eric.dumazet@gmail.com> - 2015-08-29 16:20 +0200
        Re: [PATCH] task_work: remove fifo ordering guarantee Linus Torvalds <torvalds@linux-foundation.org> - 2015-08-29 19:10 +0200
          Re: [PATCH] task_work: remove fifo ordering guarantee yalin wang <yalin.wang2010@gmail.com> - 2015-08-31 07:30 +0200
            Re: [PATCH] task_work: remove fifo ordering guarantee Al Viro <viro@ZenIV.linux.org.uk> - 2015-09-05 07:20 +0200
          Re: [PATCH] task_work: remove fifo ordering guarantee Oleg Nesterov <oleg@redhat.com> - 2015-08-31 14:50 +0200
          Re: [PATCH] task_work: remove fifo ordering guarantee Al Viro <viro@ZenIV.linux.org.uk> - 2015-09-05 07:20 +0200
            Re: [PATCH] task_work: remove fifo ordering guarantee Al Viro <viro@ZenIV.linux.org.uk> - 2015-09-05 07:50 +0200
              Re: [PATCH] task_work: remove fifo ordering guarantee Linus Torvalds <torvalds@linux-foundation.org> - 2015-09-05 22:50 +0200
      change filp_close() to use __fput_sync() ? (Was: [PATCH]  task_work: remove fifo ordering guarantee) Oleg Nesterov <oleg@redhat.com> - 2015-08-31 14:10 +0200
    Re: [PATCH] task_work: remove fifo ordering guarantee Al Viro <viro@ZenIV.linux.org.uk> - 2015-09-05 07:40 +0200

csiph-web