From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: willy@infradead.org, wei.w.wang@intel.com
Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
kvm@vger.kernel.org, linux-mm@kvack.org, mst@redhat.com,
mhocko@kernel.org, akpm@linux-foundation.org,
mawilcox@microsoft.com, david@redhat.com,
cornelia.huck@de.ibm.com, mgorman@techsingularity.net,
aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com,
liliang.opensource@gmail.com, yang.zhang.wz@gmail.com,
quan.xu@aliyun.com, nilal@redhat.com, riel@redhat.com
Subject: Re: [PATCH v18 05/10] xbitmap: add more operations
Date: Sun, 3 Dec 2017 10:50:42 +0900 [thread overview]
Message-ID: <201712031050.IAC64520.QVLFFOOJOSFtHM@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <20171201172519.GA27192@bombadil.infradead.org>
Matthew Wilcox wrote:
> On Fri, Dec 01, 2017 at 03:09:08PM +0000, Wang, Wei W wrote:
> > On Friday, December 1, 2017 9:02 PM, Tetsuo Handa wrote:
> > > If start == end is legal,
> > >
> > > for (; start < end; start = (start | (IDA_BITMAP_BITS - 1)) + 1) {
> > >
> > > makes this loop do nothing because 10 < 10 is false.
> >
> > How about "start <= end "?
>
> Don't ask Tetsuo for his opinion, write some userspace code that uses it.
>
Please be sure to prepare for "end == -1UL" case, for "start < end" will become
true when "start = (start | (IDA_BITMAP_BITS - 1)) + 1" made "start == 0" due to
overflow.
WARNING: multiple messages have this Message-ID (diff)
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: willy@infradead.org, wei.w.wang@intel.com
Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
kvm@vger.kernel.org, linux-mm@kvack.org, mst@redhat.com,
mhocko@kernel.org, akpm@linux-foundation.org,
mawilcox@microsoft.com, david@redhat.com,
cornelia.huck@de.ibm.com, mgorman@techsingularity.net,
aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com,
liliang.opensource@gmail.com, yang.zhang.wz@gmail.com,
quan.xu@aliyun.com, nilal@redhat.com, riel@redhat.com
Subject: Re: [PATCH v18 05/10] xbitmap: add more operations
Date: Sun, 3 Dec 2017 10:50:42 +0900 [thread overview]
Message-ID: <201712031050.IAC64520.QVLFFOOJOSFtHM@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <20171201172519.GA27192@bombadil.infradead.org>
Matthew Wilcox wrote:
> On Fri, Dec 01, 2017 at 03:09:08PM +0000, Wang, Wei W wrote:
> > On Friday, December 1, 2017 9:02 PM, Tetsuo Handa wrote:
> > > If start == end is legal,
> > >
> > > for (; start < end; start = (start | (IDA_BITMAP_BITS - 1)) + 1) {
> > >
> > > makes this loop do nothing because 10 < 10 is false.
> >
> > How about "start <= end "?
>
> Don't ask Tetsuo for his opinion, write some userspace code that uses it.
>
Please be sure to prepare for "end == -1UL" case, for "start < end" will become
true when "start = (start | (IDA_BITMAP_BITS - 1)) + 1" made "start == 0" due to
overflow.
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WARNING: multiple messages have this Message-ID (diff)
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: willy@infradead.org, wei.w.wang@intel.com
Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
kvm@vger.kernel.org, linux-mm@kvack.org, mst@redhat.com,
mhocko@kernel.org, akpm@linux-foundation.org,
mawilcox@microsoft.com, david@redhat.com,
cornelia.huck@de.ibm.com, mgorman@techsingularity.net,
aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com,
liliang.opensource@gmail.com, yang.zhang.wz@gmail.com,
quan.xu@aliyun.com, nilal@redhat.com, riel@redhat.com
Subject: Re: [Qemu-devel] [PATCH v18 05/10] xbitmap: add more operations
Date: Sun, 3 Dec 2017 10:50:42 +0900 [thread overview]
Message-ID: <201712031050.IAC64520.QVLFFOOJOSFtHM@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <20171201172519.GA27192@bombadil.infradead.org>
Matthew Wilcox wrote:
> On Fri, Dec 01, 2017 at 03:09:08PM +0000, Wang, Wei W wrote:
> > On Friday, December 1, 2017 9:02 PM, Tetsuo Handa wrote:
> > > If start == end is legal,
> > >
> > > for (; start < end; start = (start | (IDA_BITMAP_BITS - 1)) + 1) {
> > >
> > > makes this loop do nothing because 10 < 10 is false.
> >
> > How about "start <= end "?
>
> Don't ask Tetsuo for his opinion, write some userspace code that uses it.
>
Please be sure to prepare for "end == -1UL" case, for "start < end" will become
true when "start = (start | (IDA_BITMAP_BITS - 1)) + 1" made "start == 0" due to
overflow.
next prev parent reply other threads:[~2017-12-03 1:50 UTC|newest]
Thread overview: 167+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-29 13:55 [PATCH v18 00/10] Virtio-balloon Enhancement Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [PATCH v18 01/10] idr: add #include <linux/bug.h> Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-30 0:58 ` Matthew Wilcox
2017-11-30 0:58 ` Matthew Wilcox
2017-11-30 0:58 ` [Qemu-devel] " Matthew Wilcox
2017-11-30 0:58 ` Matthew Wilcox
2017-11-30 7:07 ` Michal Hocko
2017-11-30 7:07 ` Michal Hocko
2017-11-30 7:07 ` [Qemu-devel] " Michal Hocko
2017-11-30 7:07 ` Michal Hocko
2017-11-30 21:49 ` Andrew Morton
2017-11-30 21:49 ` Andrew Morton
2017-11-30 21:49 ` Andrew Morton
2017-11-29 13:55 ` [PATCH v18 02/10] radix tree test suite: remove ARRAY_SIZE to avoid redefinition Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [PATCH v18 03/10] xbitmap: Introduce xbitmap Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [PATCH v18 04/10] xbitmap: potential improvement Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [PATCH v18 05/10] xbitmap: add more operations Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-30 10:34 ` Tetsuo Handa
2017-11-30 10:34 ` [Qemu-devel] " Tetsuo Handa
2017-11-30 10:34 ` Tetsuo Handa
2017-11-30 13:35 ` Tetsuo Handa
2017-11-30 13:35 ` [Qemu-devel] " Tetsuo Handa
2017-11-30 13:35 ` Tetsuo Handa
2017-11-30 14:39 ` Matthew Wilcox
2017-11-30 14:39 ` Matthew Wilcox
2017-11-30 14:39 ` [Qemu-devel] " Matthew Wilcox
2017-11-30 14:39 ` Matthew Wilcox
2017-12-03 1:44 ` Tetsuo Handa
2017-12-03 1:44 ` [Qemu-devel] " Tetsuo Handa
2017-12-03 1:44 ` Tetsuo Handa
2017-12-01 8:02 ` Wei Wang
2017-12-01 8:02 ` [virtio-dev] " Wei Wang
2017-12-01 8:02 ` Wei Wang
2017-12-01 13:02 ` Tetsuo Handa
2017-12-01 13:02 ` [Qemu-devel] " Tetsuo Handa
2017-12-01 13:02 ` Tetsuo Handa
2017-12-01 14:13 ` Matthew Wilcox
2017-12-01 14:13 ` Matthew Wilcox
2017-12-01 14:13 ` [Qemu-devel] " Matthew Wilcox
2017-12-01 14:13 ` Matthew Wilcox
2017-12-01 15:09 ` Wang, Wei W
2017-12-01 15:09 ` Wang, Wei W
2017-12-01 15:09 ` [virtio-dev] " Wang, Wei W
2017-12-01 15:09 ` [Qemu-devel] " Wang, Wei W
2017-12-01 15:09 ` Wang, Wei W
2017-12-01 15:09 ` Wang, Wei W
2017-12-01 17:25 ` Matthew Wilcox
2017-12-01 17:25 ` [Qemu-devel] " Matthew Wilcox
2017-12-01 17:25 ` Matthew Wilcox
2017-12-01 17:25 ` Matthew Wilcox
2017-12-03 1:50 ` Tetsuo Handa [this message]
2017-12-03 1:50 ` [Qemu-devel] " Tetsuo Handa
2017-12-03 1:50 ` Tetsuo Handa
2017-12-07 12:01 ` Wei Wang
2017-12-07 12:01 ` Wei Wang
2017-12-07 12:01 ` [virtio-dev] " Wei Wang
2017-12-07 12:01 ` [Qemu-devel] " Wei Wang
2017-12-07 12:01 ` Wei Wang
2017-12-07 15:41 ` Michael S. Tsirkin
2017-12-07 15:41 ` [virtio-dev] " Michael S. Tsirkin
2017-12-07 15:41 ` [Qemu-devel] " Michael S. Tsirkin
2017-12-07 15:41 ` Michael S. Tsirkin
2017-12-07 15:41 ` Michael S. Tsirkin
2017-12-01 17:25 ` Matthew Wilcox
2017-12-01 8:02 ` Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [PATCH v18 06/10] virtio_ring: add a new API, virtqueue_add_one_desc Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-30 19:38 ` Michael S. Tsirkin
2017-11-30 19:38 ` [virtio-dev] " Michael S. Tsirkin
2017-11-30 19:38 ` [Qemu-devel] " Michael S. Tsirkin
2017-11-30 19:38 ` Michael S. Tsirkin
2017-12-01 8:06 ` Wei Wang
2017-12-01 8:06 ` Wei Wang
2017-12-01 8:06 ` [virtio-dev] " Wei Wang
2017-12-01 8:06 ` Wei Wang
2017-11-30 19:38 ` Michael S. Tsirkin
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [PATCH v18 07/10] virtio-balloon: VIRTIO_BALLOON_F_SG Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-30 10:35 ` Tetsuo Handa
2017-11-30 10:35 ` [Qemu-devel] " Tetsuo Handa
2017-11-30 10:35 ` Tetsuo Handa
2017-11-30 16:25 ` Wang, Wei W
2017-11-30 16:25 ` Wang, Wei W
2017-11-30 16:25 ` [virtio-dev] " Wang, Wei W
2017-11-30 16:25 ` [Qemu-devel] " Wang, Wei W
2017-11-30 16:25 ` Wang, Wei W
2017-11-30 16:25 ` Wang, Wei W
2017-12-01 15:38 ` Michael S. Tsirkin
2017-12-01 15:38 ` Michael S. Tsirkin
2017-12-01 15:38 ` [virtio-dev] " Michael S. Tsirkin
2017-12-01 15:38 ` [Qemu-devel] " Michael S. Tsirkin
2017-12-01 15:38 ` Michael S. Tsirkin
2017-12-04 3:46 ` Wei Wang
2017-12-04 3:46 ` [Qemu-devel] " Wei Wang
2017-12-04 3:46 ` Wei Wang
2017-12-04 3:46 ` Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [PATCH v18 08/10] mm: support reporting free page blocks Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [PATCH v18 09/10] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-29 13:55 ` [PATCH v18 10/10] virtio-balloon: don't report free pages when page poisoning is enabled Wei Wang
2017-11-29 13:55 ` [virtio-dev] " Wei Wang
2017-11-29 13:55 ` [Qemu-devel] " Wei Wang
2017-11-29 13:55 ` Wei Wang
2017-11-30 10:45 ` Tetsuo Handa
2017-12-01 8:06 ` Wei Wang
2017-12-01 8:06 ` [virtio-dev] " Wei Wang
2017-12-01 15:49 ` Michael S. Tsirkin
2017-12-01 15:49 ` Michael S. Tsirkin
2017-12-01 15:49 ` [virtio-dev] " Michael S. Tsirkin
2017-12-01 15:49 ` [Qemu-devel] " Michael S. Tsirkin
2017-12-01 15:49 ` Michael S. Tsirkin
2017-12-04 5:39 ` Wei Wang
2017-12-04 5:39 ` [Qemu-devel] " Wei Wang
2017-12-04 5:39 ` Wei Wang
2017-12-04 5:39 ` Wei Wang
2017-12-11 6:38 ` Wei Wang
2017-12-11 6:38 ` Wei Wang
2017-12-11 6:38 ` [virtio-dev] " Wei Wang
2017-12-11 6:38 ` [Qemu-devel] " Wei Wang
2017-12-11 6:38 ` Wei Wang
2017-12-11 13:24 ` Michael S. Tsirkin
2017-12-11 13:24 ` Michael S. Tsirkin
2017-12-11 13:24 ` [virtio-dev] " Michael S. Tsirkin
2017-12-11 13:24 ` [Qemu-devel] " Michael S. Tsirkin
2017-12-11 13:24 ` Michael S. Tsirkin
2017-12-12 12:21 ` Wei Wang
2017-12-12 12:21 ` Wei Wang
2017-12-12 12:21 ` [virtio-dev] " Wei Wang
2017-12-12 12:21 ` [Qemu-devel] " Wei Wang
2017-12-12 12:21 ` Wei Wang
2017-11-29 13:55 ` Wei Wang
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