From: Byungchul Park <byungchul.park@lge.com>
To: peterz@infradead.org, mingo@kernel.org
Cc: tglx@linutronix.de, walken@google.com, boqun.feng@gmail.com,
kirill@shutemov.name, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, iamjoonsoo.kim@lge.com,
akpm@linux-foundation.org, npiggin@gmail.com
Subject: Re: [PATCH v5 00/13] lockdep: Implement crossrelease feature
Date: Mon, 20 Feb 2017 17:38:36 +0900 [thread overview]
Message-ID: <20170220083836.GA3817@X58A-UD3R> (raw)
In-Reply-To: <1484745459-2055-1-git-send-email-byungchul.park@lge.com>
On Wed, Jan 18, 2017 at 10:17:26PM +0900, Byungchul Park wrote:
> I checked if crossrelease feature works well on my qemu-i386 machine.
> There's no problem at all to work on mine. But I wonder if it's also
> true even on other machines. Especially, on large system. Could you
> let me know if it doesn't work on yours? Or Could you let me know if
> crossrelease feature is useful? Please let me know if you need to
> backport it to another version but it's not easy. Then I can provide
> the backported version after working it.
Hello peterz,
I don't want to rush you, but I think enough time has passed. Could you
check this? I tried to apply what you recommanded at the previous spin
as much as possible. Could you?
Thanks,
Byungchul
>
> -----8<-----
>
> Change from v4
> - rebase on vanilla v4.9 tag
> - re-name pend_lock(plock) to hist_lock(xhlock)
> - allow overwriting ring buffer for hist_lock
> - unwind ring buffer instead of tagging id for each irq
> - introduce lockdep_map_cross embedding cross_lock
> - make each work of workqueue distinguishable
> - enhance comments
> (I will update the document at the next spin.)
>
> Change from v3
> - reviced document
>
> Change from v2
> - rebase on vanilla v4.7 tag
> - move lockdep data for page lock from struct page to page_ext
> - allocate plocks buffer via vmalloc instead of in struct task
> - enhanced comments and document
> - optimize performance
> - make reporting function crossrelease-aware
>
> Change from v1
> - enhanced the document
> - removed save_stack_trace() optimizing patch
> - made this based on the seperated save_stack_trace patchset
> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1182242.html
>
> Can we detect deadlocks below with original lockdep?
>
> Example 1)
>
> PROCESS X PROCESS Y
> -------------- --------------
> mutext_lock A
> lock_page B
> lock_page B
> mutext_lock A // DEADLOCK
> unlock_page B
> mutext_unlock A
> mutex_unlock A
> unlock_page B
>
> where A and B are different lock classes.
>
> No, we cannot.
>
> Example 2)
>
> PROCESS X PROCESS Y PROCESS Z
> -------------- -------------- --------------
> mutex_lock A
> lock_page B
> lock_page B
> mutext_lock A // DEADLOCK
> mutext_unlock A
> unlock_page B
> (B was held by PROCESS X)
> unlock_page B
> mutex_unlock A
>
> where A and B are different lock classes.
>
> No, we cannot.
>
> Example 3)
>
> PROCESS X PROCESS Y
> -------------- --------------
> mutex_lock A
> mutex_lock A
> wait_for_complete B // DEADLOCK
> mutex_unlock A
> complete B
> mutex_unlock A
>
> where A is a lock class and B is a completion variable.
>
> No, we cannot.
>
> Not only lock operations, but also any operations causing to wait or
> spin for something can cause deadlock unless it's eventually *released*
> by someone. The important point here is that the waiting or spinning
> must be *released* by someone.
>
> Using crossrelease feature, we can check dependency and detect deadlock
> possibility not only for typical lock, but also for lock_page(),
> wait_for_xxx() and so on, which might be released in any context.
>
> See the last patch including the document for more information.
>
> Byungchul Park (13):
> lockdep: Refactor lookup_chain_cache()
> lockdep: Fix wrong condition to print bug msgs for
> MAX_LOCKDEP_CHAIN_HLOCKS
> lockdep: Add a function building a chain between two classes
> lockdep: Refactor save_trace()
> lockdep: Pass a callback arg to check_prev_add() to handle stack_trace
> lockdep: Implement crossrelease feature
> lockdep: Make print_circular_bug() aware of crossrelease
> lockdep: Apply crossrelease to completions
> pagemap.h: Remove trailing white space
> lockdep: Apply crossrelease to PG_locked locks
> lockdep: Apply lock_acquire(release) on __Set(__Clear)PageLocked
> lockdep: Move data of CONFIG_LOCKDEP_PAGELOCK from page to page_ext
> lockdep: Crossrelease feature documentation
>
> Documentation/locking/crossrelease.txt | 1053 ++++++++++++++++++++++++++++++++
> include/linux/completion.h | 118 +++-
> include/linux/irqflags.h | 24 +-
> include/linux/lockdep.h | 129 ++++
> include/linux/mm_types.h | 4 +
> include/linux/page-flags.h | 43 +-
> include/linux/page_ext.h | 4 +
> include/linux/pagemap.h | 124 +++-
> include/linux/sched.h | 9 +
> kernel/exit.c | 9 +
> kernel/fork.c | 23 +
> kernel/locking/lockdep.c | 763 ++++++++++++++++++++---
> kernel/sched/completion.c | 54 +-
> kernel/workqueue.c | 1 +
> lib/Kconfig.debug | 30 +
> mm/filemap.c | 76 ++-
> mm/page_ext.c | 4 +
> 17 files changed, 2324 insertions(+), 144 deletions(-)
> create mode 100644 Documentation/locking/crossrelease.txt
>
> --
> 1.9.1
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prev parent reply other threads:[~2017-02-20 8:38 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-18 13:17 [PATCH v5 00/13] lockdep: Implement crossrelease feature Byungchul Park
2017-01-18 13:17 ` [PATCH v5 01/13] lockdep: Refactor lookup_chain_cache() Byungchul Park
2017-01-19 9:16 ` Boqun Feng
2017-01-19 9:52 ` Byungchul Park
2017-01-26 7:53 ` Byungchul Park
2017-01-18 13:17 ` [PATCH v5 02/13] lockdep: Fix wrong condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS Byungchul Park
2017-01-18 13:17 ` [PATCH v5 03/13] lockdep: Add a function building a chain between two classes Byungchul Park
2017-01-18 13:17 ` [PATCH v5 04/13] lockdep: Refactor save_trace() Byungchul Park
2017-01-18 13:17 ` [PATCH v5 05/13] lockdep: Pass a callback arg to check_prev_add() to handle stack_trace Byungchul Park
2017-01-26 7:43 ` Byungchul Park
2017-01-18 13:17 ` [PATCH v5 06/13] lockdep: Implement crossrelease feature Byungchul Park
2017-02-28 12:26 ` Peter Zijlstra
2017-02-28 12:45 ` Peter Zijlstra
2017-02-28 12:49 ` Peter Zijlstra
2017-03-01 6:20 ` Byungchul Park
2017-02-28 13:05 ` Peter Zijlstra
2017-02-28 13:28 ` Byungchul Park
2017-02-28 13:35 ` Peter Zijlstra
2017-02-28 14:00 ` Byungchul Park
2017-02-28 13:10 ` Peter Zijlstra
2017-02-28 13:24 ` Byungchul Park
2017-02-28 18:29 ` Peter Zijlstra
2017-03-01 4:40 ` Byungchul Park
2017-03-01 10:45 ` Peter Zijlstra
2017-03-01 12:10 ` Byungchul Park
2017-02-28 13:40 ` Peter Zijlstra
2017-03-01 5:43 ` Byungchul Park
2017-03-01 12:28 ` Peter Zijlstra
2017-03-02 13:40 ` Peter Zijlstra
2017-03-03 0:17 ` Byungchul Park
2017-03-03 8:14 ` Peter Zijlstra
2017-03-03 9:13 ` Peter Zijlstra
2017-03-03 9:32 ` Peter Zijlstra
2017-03-05 3:33 ` Byungchul Park
2017-03-05 3:08 ` Byungchul Park
2017-03-07 11:42 ` Peter Zijlstra
2017-03-03 0:39 ` Byungchul Park
2017-02-28 15:49 ` Peter Zijlstra
2017-03-01 5:17 ` Byungchul Park
2017-03-01 6:18 ` Byungchul Park
2017-03-02 2:52 ` Byungchul Park
2017-02-28 18:15 ` Peter Zijlstra
2017-03-01 7:21 ` Byungchul Park
2017-03-01 10:43 ` Peter Zijlstra
2017-03-01 12:27 ` Byungchul Park
2017-03-02 4:20 ` Matthew Wilcox
2017-03-02 4:45 ` byungchul.park
2017-03-02 14:39 ` Matthew Wilcox
2017-03-02 23:50 ` Byungchul Park
2017-03-05 8:01 ` Byungchul Park
2017-03-14 7:36 ` Byungchul Park
2017-03-02 13:41 ` Peter Zijlstra
2017-03-02 23:43 ` Byungchul Park
2017-01-18 13:17 ` [PATCH v5 07/13] lockdep: Make print_circular_bug() aware of crossrelease Byungchul Park
2017-01-18 13:17 ` [PATCH v5 08/13] lockdep: Apply crossrelease to completions Byungchul Park
2017-01-18 13:17 ` [PATCH v5 09/13] pagemap.h: Remove trailing white space Byungchul Park
2017-01-18 13:17 ` [PATCH v5 10/13] lockdep: Apply crossrelease to PG_locked locks Byungchul Park
2017-01-18 13:17 ` [PATCH v5 11/13] lockdep: Apply lock_acquire(release) on __Set(__Clear)PageLocked Byungchul Park
2017-01-18 13:17 ` [PATCH v5 12/13] lockdep: Move data of CONFIG_LOCKDEP_PAGELOCK from page to page_ext Byungchul Park
2017-01-18 13:17 ` [PATCH v5 13/13] lockdep: Crossrelease feature documentation Byungchul Park
2017-01-20 9:08 ` [REVISED DOCUMENT] " Byungchul Park
2017-02-20 8:38 ` Byungchul Park [this message]
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