All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sean Christopherson <seanjc@google.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,
	 Shuah Khan <skhan@linuxfoundation.org>,
	Thomas Gleixner <tglx@kernel.org>,
	 Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	 Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org,  "H. Peter Anvin" <hpa@zytor.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Juergen Gross <jgross@suse.com>,
	 Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Paul Durrant <paul@xen.org>,  Jonathan Cameron <jic23@kernel.org>,
	Sascha Bischoff <Sascha.Bischoff@arm.com>,
	 Marc Zyngier <maz@kernel.org>, Joey Gouly <joey.gouly@arm.com>,
	Jack Allister <jalliste@amazon.com>,
	 Dongli Zhang <dongli.zhang@oracle.com>,
	joe.jin@oracle.com, kvm@vger.kernel.org,
	 linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	 xen-devel@lists.xenproject.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v7 05/36] KVM: x86: Fold __get_kvmclock() into get_kvmclock()
Date: Tue, 28 Jul 2026 16:06:09 -0700	[thread overview]
Message-ID: <amk14dmn5j7Oov1B@google.com> (raw)
In-Reply-To: <20260728144954.355376-6-dwmw2@infradead.org>

On Tue, Jul 28, 2026, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
> 
> There is no need for the separate __get_kvmclock() helper; just inline
> its body into get_kvmclock() within the seqcount retry loop.

Actually, there ends up being quite a bit of value if we rework the inner helper
to be all about the master clock mode.  If we go that route, then the main loop
is pretty self-explanatory, we can use early returns instead of continues and
subtle fall-throughs, and the indentation levels go down.

	do {
		data->flags = 0;

		seq = read_seqcount_begin(&ka->pvclock_sc);
		if (!__get_kvmclock_master_clock(kvm, data))
			data->clock = get_kvmclock_base_ns() + ka->kvmclock_offset;
	} while (read_seqcount_retry(&ka->pvclock_sc, seq));

  reply	other threads:[~2026-07-28 23:06 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-28 14:39 [PATCH v7 00/36] Cleaning up the KVM clock mess David Woodhouse
2026-07-28 14:39 ` [PATCH v7 01/36] KVM: x86: Improve accuracy of KVM clock when TSC scaling is in force David Woodhouse
2026-07-28 14:39 ` [PATCH v7 02/36] KVM: x86: Explicitly disable TSC scaling without CONSTANT_TSC David Woodhouse
2026-07-28 14:39 ` [PATCH v7 03/36] KVM: x86: Activate master clock immediately on vCPU creation David Woodhouse
2026-07-28 15:17   ` sashiko-bot
2026-07-28 14:39 ` [PATCH v7 04/36] KVM: x86: Avoid NTP frequency skew for KVM clock on 32-bit host David Woodhouse
2026-07-28 14:39 ` [PATCH v7 05/36] KVM: x86: Fold __get_kvmclock() into get_kvmclock() David Woodhouse
2026-07-28 23:06   ` Sean Christopherson [this message]
2026-07-28 14:39 ` [PATCH v7 06/36] KVM: x86: Drop CPU pinning in get_kvmclock() David Woodhouse
2026-07-28 14:39 ` [PATCH v7 07/36] KVM: x86: Restructure get_kvmclock() David Woodhouse
2026-07-28 15:11   ` sashiko-bot
2026-07-28 23:02     ` Sean Christopherson
2026-07-28 23:04   ` Sean Christopherson
2026-07-28 14:39 ` [PATCH v7 08/36] KVM: x86: Fix KVM clock precision in get_kvmclock() with TSC scaling David Woodhouse
2026-07-28 14:39 ` [PATCH v7 09/36] KVM: x86: Use get_kvmclock() in kvm_get_wall_clock_epoch() David Woodhouse
2026-07-28 14:39 ` [PATCH v7 10/36] KVM: x86: Fix compute_guest_tsc() to handle negative time deltas David Woodhouse
2026-07-28 14:39 ` [PATCH v7 11/36] KVM: x86: Restructure kvm_guest_time_update() for TSC upscaling David Woodhouse
2026-07-28 15:11   ` sashiko-bot
2026-07-28 14:39 ` [PATCH v7 12/36] KVM: x86: Simplify and comment kvm_get_time_scale() David Woodhouse
2026-07-28 14:39 ` [PATCH v7 13/36] KVM: x86: Remove implicit rdtsc() from kvm_compute_l1_tsc_offset() David Woodhouse
2026-07-28 14:39 ` [PATCH v7 14/36] KVM: x86: Improve synchronization in kvm_synchronize_tsc() David Woodhouse
2026-07-28 15:08   ` sashiko-bot
2026-07-28 14:39 ` [PATCH v7 15/36] KVM: x86: Kill last_tsc_{nsec,write,offset} fields David Woodhouse
2026-07-28 15:09   ` sashiko-bot
2026-07-28 14:39 ` [PATCH v7 16/36] KVM: x86: Replace nr_vcpus_matched_tsc count with all_vcpus_matched_tsc bool David Woodhouse
2026-07-28 14:39 ` [PATCH v7 17/36] KVM: x86: Allow KVM master clock mode when TSCs are offset from each other David Woodhouse
2026-07-28 14:39 ` [PATCH v7 18/36] KVM: x86: Factor out kvm_use_master_clock() David Woodhouse
2026-07-28 14:39 ` [PATCH v7 19/36] KVM: x86: Avoid gratuitous global clock updates David Woodhouse
2026-07-28 14:40 ` [PATCH v7 20/36] KVM: x86/xen: Prevent runstate times from becoming negative David Woodhouse
2026-07-28 15:15   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 21/36] KVM: x86: Avoid redundant masterclock updates from multiple vCPUs David Woodhouse
2026-07-28 15:23   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 22/36] KVM: x86: Remove runtime Xen TSC frequency CPUID update David Woodhouse
2026-07-28 15:18   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 23/36] KVM: x86: Re-synchronize TSC after KVM_SET_TSC_KHZ David Woodhouse
2026-07-28 15:19   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 24/36] KVM: x86: Use ktime_get_snapshot_id() for master clock David Woodhouse
2026-07-28 15:21   ` sashiko-bot
2026-07-28 22:59     ` Sean Christopherson
2026-07-28 14:40 ` [PATCH v7 25/36] KVM: x86: Compute kvmclock base without pvclock_gtod_data David Woodhouse
2026-07-28 14:40 ` [PATCH v7 26/36] KVM: x86: Cache host vclock_mode for masterclock eligibility checks David Woodhouse
2026-07-28 15:26   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 27/36] KVM: x86: Remove pvclock_gtod_data and private timekeeping code David Woodhouse
2026-07-28 15:25   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 28/36] KVM: x86: Activate master clock from kvm_arch_init_vm() David Woodhouse
2026-07-28 15:31   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 29/36] UAPI: x86: Move pvclock-abi to UAPI for x86 platforms David Woodhouse
2026-07-28 14:40 ` [PATCH v7 30/36] KVM: selftests: Use UAPI pvclock-abi.h in xen_shinfo_test David Woodhouse
2026-07-28 14:40 ` [PATCH v7 31/36] KVM: x86: Add KVM_[GS]ET_CLOCK_GUEST for accurate KVM clock migration David Woodhouse
2026-07-28 14:40 ` [PATCH v7 32/36] KVM: x86: Add KVM_VCPU_TSC_SCALE and fix the documentation on TSC migration David Woodhouse
2026-07-28 15:26   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 33/36] KVM: selftests: Add KVM/PV clock selftest to prove timer correction David Woodhouse
2026-07-28 14:40 ` [PATCH v7 34/36] KVM: selftests: Add master clock offset test David Woodhouse
2026-07-28 15:22   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 35/36] KVM: selftests: Add Xen/generic CPUID timing leaf test David Woodhouse
2026-07-28 15:23   ` sashiko-bot
2026-07-28 14:40 ` [PATCH v7 36/36] KVM: selftests: Add Xen runstate migration test David Woodhouse
2026-07-28 23:18 ` [PATCH v7 00/36] Cleaning up the KVM clock mess Sean Christopherson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=amk14dmn5j7Oov1B@google.com \
    --to=seanjc@google.com \
    --cc=Sascha.Bischoff@arm.com \
    --cc=boris.ostrovsky@oracle.com \
    --cc=bp@alien8.de \
    --cc=corbet@lwn.net \
    --cc=dave.hansen@linux.intel.com \
    --cc=dongli.zhang@oracle.com \
    --cc=dwmw2@infradead.org \
    --cc=hpa@zytor.com \
    --cc=jalliste@amazon.com \
    --cc=jgross@suse.com \
    --cc=jic23@kernel.org \
    --cc=joe.jin@oracle.com \
    --cc=joey.gouly@arm.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=maz@kernel.org \
    --cc=mingo@redhat.com \
    --cc=paul@xen.org \
    --cc=pbonzini@redhat.com \
    --cc=skhan@linuxfoundation.org \
    --cc=tglx@kernel.org \
    --cc=vkuznets@redhat.com \
    --cc=x86@kernel.org \
    --cc=xen-devel@lists.xenproject.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.