From: "Wu, Feng" <feng.wu@intel.com>
To: "Radim Krcmár" <rkrcmar@redhat.com>
Cc: "pbonzini@redhat.com" <pbonzini@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Wu, Feng" <feng.wu@intel.com>
Subject: RE: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts
Date: Fri, 22 Jan 2016 05:12:44 +0000 [thread overview]
Message-ID: <E959C4978C3B6342920538CF579893F00C2C1C3B@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <20160121194950.GC17514@potion.brq.redhat.com>
> -----Original Message-----
> From: Radim Krčmář [mailto:rkrcmar@redhat.com]
> Sent: Friday, January 22, 2016 3:50 AM
> To: Wu, Feng <feng.wu@intel.com>
> Cc: pbonzini@redhat.com; linux-kernel@vger.kernel.org;
> kvm@vger.kernel.org
> Subject: Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-
> priority interrupts
>
> 2016-01-20 09:42+0800, Feng Wu:
> > Use vector-hashing to deliver lowest-priority interrupts, As an
> > example, modern Intel CPUs in server platform use this method to
> > handle lowest-priority interrupts.
> >
> > Signed-off-by: Feng Wu <feng.wu@intel.com>
> > ---
>
> Functionality looks good, so I had a lot of stylistic comments, sorry :)
Any comments are welcome! Thank you! :)
>
> > + const unsigned long *bitmap, u32 bitmap_size)
> > +{
> > + u32 mod;
> > + int i, idx = 0;
> > +
> > + mod = vector % dest_vcpus;
> > +
> > + for (i = 0; i <= mod; i++) {
> > + idx = find_next_bit(bitmap, bitmap_size, idx) + 1;
>
> I'd remove this "+ 1". Current users don't check for errors and always
> do "- 1". The new error value could be 'idx = bitmap_size', with u32 as
> return type.
>
Does the following code look good to you:
u32 mod;
int i, idx = -1;
mod = vector % dest_vcpus;
for (i = 0; i <= mod; i++) {
idx = find_next_bit(bitmap, bitmap_size, idx + 1);
BUG_ON(idx == bitmap_size);
}
return idx;
Thanks,
Feng
next prev parent reply other threads:[~2016-01-22 5:13 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-20 1:42 [PATCH v3 0/4] VT-d posted-interrupts follow ups Feng Wu
2016-01-20 1:42 ` [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination Feng Wu
2016-01-21 3:05 ` Yang Zhang
2016-01-21 3:14 ` Wu, Feng
2016-01-21 3:34 ` Yang Zhang
2016-01-21 4:42 ` Wu, Feng
2016-01-21 4:54 ` Tian, Kevin
2016-01-21 4:59 ` Yang Zhang
2016-01-21 5:07 ` Wu, Feng
2016-01-21 5:35 ` Yang Zhang
2016-01-21 5:41 ` Wu, Feng
2016-01-21 5:44 ` Yang Zhang
2016-01-21 16:35 ` rkrcmar
2016-01-22 2:03 ` Yang Zhang
2016-01-22 13:31 ` rkrcmar
2016-01-25 1:49 ` Yang Zhang
2016-01-25 13:59 ` rkrcmar
2016-01-26 1:44 ` Yang Zhang
2016-01-26 18:22 ` rkrcmar
2016-01-27 2:07 ` Yang Zhang
2016-01-27 15:05 ` rkrcmar
2016-01-21 16:19 ` Radim Krčmář
2016-01-22 1:49 ` Wu, Feng
2016-01-22 13:05 ` Radim Krcmár
2016-01-25 12:22 ` Paolo Bonzini
2016-01-25 12:26 ` Wu, Feng
2016-01-25 12:38 ` Paolo Bonzini
2016-01-25 12:48 ` Wu, Feng
2016-01-25 14:05 ` Radim Krcmár
2016-01-26 0:57 ` Wu, Feng
2016-01-20 1:42 ` [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Feng Wu
2016-01-21 5:23 ` Yang Zhang
2016-01-21 5:33 ` Wu, Feng
2016-01-21 5:42 ` Yang Zhang
2016-01-21 5:46 ` Wu, Feng
2016-01-21 5:57 ` Yang Zhang
2016-01-21 6:02 ` Wu, Feng
2016-01-21 6:07 ` Yang Zhang
2016-01-21 17:21 ` rkrcmar
2016-01-22 2:01 ` Wu, Feng
2016-01-22 4:00 ` Yang Zhang
2016-01-22 13:49 ` rkrcmar
2016-01-21 19:49 ` Radim Krčmář
2016-01-22 5:12 ` Wu, Feng [this message]
2016-01-22 14:01 ` Radim Krcmár
2016-01-25 12:25 ` Paolo Bonzini
2016-01-25 15:20 ` Radim Krcmár
2016-01-25 16:14 ` Paolo Bonzini
2016-01-26 1:10 ` Wu, Feng
2016-01-20 1:42 ` [PATCH v3 3/4] KVM: x86: Add lowest-priority support for vt-d posted-interrupts Feng Wu
2016-01-21 20:16 ` Radim Krčmář
2016-01-22 5:12 ` Wu, Feng
2016-01-22 14:07 ` Radim Krcmár
2016-01-20 1:42 ` [PATCH v3 4/4] KVM/VMX: Add host irq information in trace event when updating IRTE for posted interrupts Feng Wu
2016-01-21 20:19 ` Radim Krčmář
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