All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nadav Amit <nadav.amit@gmail.com>
To: Roman Kagan <rkagan@virtuozzo.com>
Cc: "Vitaly Kuznetsov" <vkuznets@redhat.com>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	"Haiyang Zhang" <haiyangz@microsoft.com>,
	"Stephen Hemminger" <sthemmin@microsoft.com>,
	"Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH v2 1/4] x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h
Date: Tue, 27 Nov 2018 17:49:29 -0800	[thread overview]
Message-ID: <8A215F49-BB8F-4E93-AC62-EC33B4734F24@gmail.com> (raw)
In-Reply-To: <20181127184835.GA5147@rkaganip.lan>

> On Nov 27, 2018, at 10:48 AM, Roman Kagan <rkagan@virtuozzo.com> wrote:
> 
> On Tue, Nov 27, 2018 at 02:10:49PM +0100, Vitaly Kuznetsov wrote:
>> Roman Kagan <rkagan@virtuozzo.com> writes:
>>> On Mon, Nov 26, 2018 at 04:47:29PM +0100, Vitaly Kuznetsov wrote:
>>> I personally tend to prefer masks over bitfields, so I'd rather do the
>>> consolidation in the opposite direction: use the definitions in
>>> hyperv-tlfs.h and replace those unions/bitfields elsewhere.  (I vaguely
>>> remember posting such a patchset a couple of years ago but I lacked the
>>> motivation to complete it).
>> 
>> Are there any known advantages of using masks over bitfields or the
>> resulting binary code is the same?
> 
> Strictly speaking bitwise ops are portable while bitfields are not, but
> I guess this is not much of an issue with gcc which is dependable to
> produce the right thing.
> 
> I came to dislike the bitfields for the false feeling of atomicity of
> assignment while most of the time they are read-modify-write operations.
> 
> And no, I don't feel strong about it, so if nobody backs me on this I
> give up :)

Last time I tried to push a change from bitmasks to bitfields I failed:
https://lkml.org/lkml/2014/9/16/245

On a different note: how come all of the hyper-v structs are not marked
with the “packed" attribute?

  reply	other threads:[~2018-11-28  1:49 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-26 15:47 [PATCH v2 0/4] x86/kvm/hyper-v: Implement Direct Mode for synthetic timers Vitaly Kuznetsov
2018-11-26 15:47 ` [PATCH v2 1/4] x86/hyper-v: move synic/stimer control structures definitions to hyperv-tlfs.h Vitaly Kuznetsov
2018-11-26 17:00   ` Michael Kelley
2018-11-26 20:04   ` Roman Kagan
2018-11-27 13:10     ` Vitaly Kuznetsov
2018-11-27 15:52       ` Michael Kelley
2018-11-27 16:32         ` Vitaly Kuznetsov
2018-11-27 18:48       ` Roman Kagan
2018-11-28  1:49         ` Nadav Amit [this message]
2018-11-28 10:37           ` Vitaly Kuznetsov
2018-11-28 13:07             ` Thomas Gleixner
2018-11-28 17:55               ` Nadav Amit
2018-11-29 11:36                 ` Vitaly Kuznetsov
2018-11-29 19:22                   ` Thomas Gleixner
2018-11-29  7:52               ` Roman Kagan
2018-11-28  8:40         ` Paolo Bonzini
2018-11-26 15:47 ` [PATCH v2 2/4] x86/kvm/hyper-v: use stimer config definition from hyperv-tlfs.h Vitaly Kuznetsov
2018-11-26 15:47 ` [PATCH v2 3/4] x86/kvm/hyper-v: direct mode for synthetic timers Vitaly Kuznetsov
2018-11-26 16:44   ` Paolo Bonzini
2018-11-26 17:14     ` Vitaly Kuznetsov
2018-11-27  8:37     ` Roman Kagan
2018-11-27 13:54       ` Paolo Bonzini
2018-11-27 19:05         ` Roman Kagan
2018-11-28  8:43           ` Paolo Bonzini
2018-11-27  8:21   ` Roman Kagan
2018-12-03 17:12   ` Roman Kagan
2018-12-04 12:36     ` Vitaly Kuznetsov
2018-12-10 12:06   ` Roman Kagan
2018-12-10 12:54     ` Vitaly Kuznetsov
2018-12-10 13:21       ` Roman Kagan
2018-12-10 14:53         ` Vitaly Kuznetsov
2018-11-26 15:47 ` [PATCH v2 4/4] x86/kvm/hyper-v: avoid open-coding stimer_mark_pending() in kvm_hv_notify_acked_sint() Vitaly Kuznetsov
2018-11-26 16:45   ` Paolo Bonzini
2018-11-27  8:49   ` Roman Kagan
2018-11-26 16:45 ` [PATCH v2 0/4] x86/kvm/hyper-v: Implement Direct Mode for synthetic timers Paolo Bonzini

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=8A215F49-BB8F-4E93-AC62-EC33B4734F24@gmail.com \
    --to=nadav.amit@gmail.com \
    --cc=Michael.H.Kelley@microsoft.com \
    --cc=haiyangz@microsoft.com \
    --cc=kvm@vger.kernel.org \
    --cc=kys@microsoft.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=rkagan@virtuozzo.com \
    --cc=rkrcmar@redhat.com \
    --cc=sthemmin@microsoft.com \
    --cc=vkuznets@redhat.com \
    --cc=x86@kernel.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.