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From: Guenter Roeck <linux@roeck-us.net>
To: Ben Gardon <bgardon@google.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Peter Shier <pshier@google.com>,
	Peter Feiner <pfeiner@google.com>,
	Junaid Shahid <junaids@google.com>,
	Jim Mattson <jmattson@google.com>,
	Yulei Zhang <yulei.kernel@gmail.com>,
	Wanpeng Li <kernellwp@gmail.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Xiao Guangrong <xiaoguangrong.eric@gmail.com>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Davidlohr Bueso <dbueso@suse.de>,
	Waiman Long <longman@redhat.com>
Subject: Re: [PATCH v2 06/28] locking/rwlocks: Add contention detection for rwlocks
Date: Tue, 9 Feb 2021 12:39:08 -0800	[thread overview]
Message-ID: <20210209203908.GA255655@roeck-us.net> (raw)
In-Reply-To: <20210202185734.1680553-7-bgardon@google.com>

On Tue, Feb 02, 2021 at 10:57:12AM -0800, Ben Gardon wrote:
> rwlocks do not currently have any facility to detect contention
> like spinlocks do. In order to allow users of rwlocks to better manage
> latency, add contention detection for queued rwlocks.
> 
> CC: Ingo Molnar <mingo@redhat.com>
> CC: Will Deacon <will@kernel.org>
> Acked-by: Peter Zijlstra <peterz@infradead.org>
> Acked-by: Davidlohr Bueso <dbueso@suse.de>
> Acked-by: Waiman Long <longman@redhat.com>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Ben Gardon <bgardon@google.com>

When building mips:defconfig, this patch results in:

Error log:
In file included from include/linux/spinlock.h:90,
                 from include/linux/ipc.h:5,
                 from include/uapi/linux/sem.h:5,
                 from include/linux/sem.h:5,
                 from include/linux/compat.h:14,
                 from arch/mips/kernel/asm-offsets.c:12:
arch/mips/include/asm/spinlock.h:17:28: error: redefinition of 'queued_spin_unlock'
   17 | #define queued_spin_unlock queued_spin_unlock
      |                            ^~~~~~~~~~~~~~~~~~
arch/mips/include/asm/spinlock.h:22:20: note: in expansion of macro 'queued_spin_unlock'
   22 | static inline void queued_spin_unlock(struct qspinlock *lock)
      |                    ^~~~~~~~~~~~~~~~~~
In file included from include/asm-generic/qrwlock.h:17,
                 from ./arch/mips/include/generated/asm/qrwlock.h:1,
                 from arch/mips/include/asm/spinlock.h:13,
                 from include/linux/spinlock.h:90,
                 from include/linux/ipc.h:5,
                 from include/uapi/linux/sem.h:5,
                 from include/linux/sem.h:5,
                 from include/linux/compat.h:14,
                 from arch/mips/kernel/asm-offsets.c:12:
include/asm-generic/qspinlock.h:94:29: note: previous definition of 'queued_spin_unlock' was here
   94 | static __always_inline void queued_spin_unlock(struct qspinlock *lock)
      |                             ^~~~~~~~~~~~~~~~~~

Bisect log attached.

Guenter

---
# bad: [a4bfd8d46ac357c12529e4eebb6c89502b03ecc9] Add linux-next specific files for 20210209
# good: [92bf22614b21a2706f4993b278017e437f7785b3] Linux 5.11-rc7
git bisect start 'HEAD' 'v5.11-rc7'
# good: [a8eb921ba7e8e77d994a1c6c69c8ef08456ecf53] Merge remote-tracking branch 'crypto/master'
git bisect good a8eb921ba7e8e77d994a1c6c69c8ef08456ecf53
# good: [21d507c41bdf83f6afc0e02976e43c10badfc6cd] Merge remote-tracking branch 'spi/for-next'
git bisect good 21d507c41bdf83f6afc0e02976e43c10badfc6cd
# bad: [30cd4c688a3bcf324f011d7716044b1a4681efc1] Merge remote-tracking branch 'soundwire/next'
git bisect bad 30cd4c688a3bcf324f011d7716044b1a4681efc1
# bad: [c43d2173d3eb4047bb62a7a393a298a1032cce18] Merge remote-tracking branch 'drivers-x86/for-next'
git bisect bad c43d2173d3eb4047bb62a7a393a298a1032cce18
# good: [973e9d8622a6fecc52f639680cbbde1519e1fcf8] Merge remote-tracking branch 'rcu/rcu/next'
git bisect good 973e9d8622a6fecc52f639680cbbde1519e1fcf8
# bad: [7b2aaf51d499e0372cbecafad04582c71ad03c73] Merge remote-tracking branch 'kvm/next'
git bisect bad 7b2aaf51d499e0372cbecafad04582c71ad03c73
# good: [04548ed0206ca895c8edd6a078c20a218423890b] KVM: SVM: Replace hard-coded value with #define
git bisect good 04548ed0206ca895c8edd6a078c20a218423890b
# bad: [92f4d400a407235783afd4399fa26c4c665024b5] KVM: x86/xen: Fix __user pointer handling for hypercall page installation
git bisect bad 92f4d400a407235783afd4399fa26c4c665024b5
# good: [ed5e484b79e8a9b8be714bd85b6fc70bd6dc99a7] KVM: x86/mmu: Ensure forward progress when yielding in TDP MMU iter
git bisect good ed5e484b79e8a9b8be714bd85b6fc70bd6dc99a7
# bad: [f3d4b4b1dc1c5fb9ea17cac14133463bfe72f170] sched: Add cond_resched_rwlock
git bisect bad f3d4b4b1dc1c5fb9ea17cac14133463bfe72f170
# good: [f1b3b06a058bb5c636ffad0afae138fe30775881] KVM: x86/mmu: Clear dirtied pages mask bit before early break
git bisect good f1b3b06a058bb5c636ffad0afae138fe30775881
# bad: [26128cb6c7e6731fe644c687af97733adfdb5ee9] locking/rwlocks: Add contention detection for rwlocks
git bisect bad 26128cb6c7e6731fe644c687af97733adfdb5ee9
# good: [7cca2d0b7e7d9f3cd740d41afdc00051c9b508a0] KVM: x86/mmu: Protect TDP MMU page table memory with RCU
git bisect good 7cca2d0b7e7d9f3cd740d41afdc00051c9b508a0
# first bad commit: [26128cb6c7e6731fe644c687af97733adfdb5ee9] locking/rwlocks: Add contention detection for rwlocks

  reply	other threads:[~2021-02-10  0:08 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-02 18:57 [PATCH v2 00/28] Allow parallel MMU operations with TDP MMU Ben Gardon
2021-02-02 18:57 ` [PATCH v2 01/28] KVM: x86/mmu: change TDP MMU yield function returns to match cond_resched Ben Gardon
2021-02-02 18:57 ` [PATCH v2 02/28] KVM: x86/mmu: Add comment on __tdp_mmu_set_spte Ben Gardon
2021-02-02 18:57 ` [PATCH v2 03/28] KVM: x86/mmu: Add lockdep when setting a TDP MMU SPTE Ben Gardon
2021-02-02 18:57 ` [PATCH v2 04/28] KVM: x86/mmu: Don't redundantly clear TDP MMU pt memory Ben Gardon
2021-02-02 18:57 ` [PATCH v2 05/28] KVM: x86/mmu: Factor out handling of removed page tables Ben Gardon
2021-02-02 18:57 ` [PATCH v2 06/28] locking/rwlocks: Add contention detection for rwlocks Ben Gardon
2021-02-09 20:39   ` Guenter Roeck [this message]
2021-02-09 21:46     ` Waiman Long
2021-02-09 22:25       ` Guenter Roeck
2021-02-10  0:27         ` Waiman Long
2021-02-10  0:41           ` Waiman Long
2021-02-10  6:04           ` Guenter Roeck
2021-02-10 14:57             ` Waiman Long
2021-02-10  3:32   ` Waiman Long
2021-02-10 15:15     ` Waiman Long
2021-02-02 18:57 ` [PATCH v2 07/28] sched: Add needbreak " Ben Gardon
2021-02-02 18:57 ` [PATCH v2 08/28] sched: Add cond_resched_rwlock Ben Gardon
2021-02-02 18:57 ` [PATCH v2 09/28] KVM: x86/mmu: Fix braces in kvm_recover_nx_lpages Ben Gardon
2021-02-02 18:57 ` [PATCH v2 10/28] KVM: x86/mmu: Fix TDP MMU zap collapsible SPTEs Ben Gardon
2021-02-03  9:43   ` Paolo Bonzini
2021-02-02 18:57 ` [PATCH v2 11/28] KVM: x86/mmu: Merge flush and non-flush tdp_mmu_iter_cond_resched Ben Gardon
2021-02-02 18:57 ` [PATCH v2 12/28] KVM: x86/mmu: Rename goal_gfn to next_last_level_gfn Ben Gardon
2021-02-02 18:57 ` [PATCH v2 13/28] KVM: x86/mmu: Ensure forward progress when yielding in TDP MMU iter Ben Gardon
2021-02-05 23:42   ` Sean Christopherson
2021-02-02 18:57 ` [PATCH v2 14/28] KVM: x86/mmu: Yield in TDU MMU iter even if no SPTES changed Ben Gardon
2021-02-02 18:57 ` [PATCH v2 15/28] KVM: x86/mmu: Skip no-op changes in TDP MMU functions Ben Gardon
2021-02-02 18:57 ` [PATCH v2 16/28] KVM: x86/mmu: Clear dirtied pages mask bit before early break Ben Gardon
2021-02-02 18:57 ` [PATCH v2 17/28] KVM: x86/mmu: Protect TDP MMU page table memory with RCU Ben Gardon
2021-02-02 18:57 ` [PATCH v2 18/28] KVM: x86/mmu: Use an rwlock for the x86 MMU Ben Gardon
2021-02-02 18:57 ` [PATCH v2 19/28] KVM: x86/mmu: Factor out functions to add/remove TDP MMU pages Ben Gardon
2021-02-02 18:57 ` [PATCH v2 20/28] KVM: x86/mmu: Use atomic ops to set SPTEs in TDP MMU map Ben Gardon
2021-02-03  2:48   ` kernel test robot
2021-02-03 11:14   ` Paolo Bonzini
2021-02-06  0:26     ` Sean Christopherson
2021-02-08 10:32       ` Paolo Bonzini
2021-04-01 10:32   ` Paolo Bonzini
2021-04-01 16:50     ` Ben Gardon
2021-04-01 17:32       ` Paolo Bonzini
2021-04-01 18:09         ` Sean Christopherson
2021-02-02 18:57 ` [PATCH v2 21/28] KVM: x86/mmu: Flush TLBs after zap in TDP MMU PF handler Ben Gardon
2021-02-06  0:29   ` Sean Christopherson
2021-02-02 18:57 ` [PATCH v2 22/28] KVM: x86/mmu: Mark SPTEs in disconnected pages as removed Ben Gardon
2021-02-03 11:17   ` Paolo Bonzini
2021-02-02 18:57 ` [PATCH v2 23/28] KVM: x86/mmu: Allow parallel page faults for the TDP MMU Ben Gardon
2021-02-03 12:39   ` Paolo Bonzini
2021-02-03 17:46     ` Ben Gardon
2021-02-03 18:30       ` Paolo Bonzini
2021-02-06  0:12         ` Sean Christopherson
2021-02-02 18:57 ` [PATCH v2 24/28] KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock Ben Gardon
2021-02-03 11:25   ` Paolo Bonzini
2021-02-03 11:26   ` Paolo Bonzini
2021-02-03 18:31     ` Ben Gardon
2021-02-03 18:32       ` Paolo Bonzini
2021-02-02 18:57 ` [PATCH v2 25/28] KVM: x86/mmu: Allow zapping collapsible SPTEs to use MMU " Ben Gardon
2021-02-03 11:34   ` Paolo Bonzini
2021-02-03 18:51     ` Ben Gardon
2021-02-02 18:57 ` [PATCH v2 26/28] KVM: x86/mmu: Allow enabling / disabling dirty logging under " Ben Gardon
2021-02-03 11:38   ` Paolo Bonzini
2021-02-02 18:57 ` [PATCH v2 27/28] KVM: selftests: Add backing src parameter to dirty_log_perf_test Ben Gardon
2021-02-02 18:57 ` [PATCH v2 28/28] KVM: selftests: Disable dirty logging with vCPUs running Ben Gardon
2021-02-03 10:07   ` Paolo Bonzini
2021-02-03 11:00 ` [PATCH v2 00/28] Allow parallel MMU operations with TDP MMU Paolo Bonzini
2021-02-03 17:54   ` Sean Christopherson
2021-02-03 18:13     ` Paolo Bonzini

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