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Groups > linux.kernel > #1243091
| From | "Hillf Danton" <hillf.zj@alibaba-inc.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI |
| Date | 2015-10-09 09:40 +0200 |
| Message-ID | <qhArv-3UI-9@gated-at.bofh.it> (permalink) |
| References | <qhAhP-3Jz-13@gated-at.bofh.it> <qhAhP-3Jz-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
> >> @@ -109,8 +109,8 @@ static void ext4_finish_bio(struct bio *bio)
> >> if (bio->bi_error)
> >> buffer_io_error(bh);
> >> } while ((bh = bh->b_this_page) != head);
> >> - bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
> >> local_irq_restore(flags);
> >
> > What if it takes 100ms to unlock after IRQ restored?
>
> I'm not sure I understand in what direction you are going? Care to
> elaborate?
>
Your change introduces extra time cost the lock waiter has to pay in
the case that irq happens before the lock is released.
> >> + bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
> >> if (!under_io) {
> >> #ifdef CONFIG_EXT4_FS_ENCRYPTION
> >> if (ctx)
> >> --
> >> 2.5.0
> >
--
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Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Nikolay Borisov <kernel@kyup.com> - 2015-10-09 09:30 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI "Hillf Danton" <hillf.zj@alibaba-inc.com> - 2015-10-09 09:40 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Nikolay Borisov <kernel@kyup.com> - 2015-10-09 10:10 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Jan Kara <jack@suse.cz> - 2015-10-12 15:50 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Nikolay Borisov <kernel@kyup.com> - 2015-10-12 17:00 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Jan Kara <jack@suse.cz> - 2015-10-13 10:20 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Nikolay Borisov <kernel@kyup.com> - 2015-10-13 12:40 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Jan Kara <jack@suse.cz> - 2015-10-13 15:20 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Nikolay Borisov <kernel@kyup.com> - 2015-10-14 11:10 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Nikolay Borisov <kernel@kyup.com> - 2015-10-16 10:10 +0200
Re: [RFC PATCH 1/2] ext4: Fix possible deadlock with local interrupts disabled and page-draining IPI Jan Kara <jack@suse.cz> - 2015-10-16 15:00 +0200
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