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Date: Wed, 03 Jan 2018 16:56:47 +0800
From: Wei Wang <wei.w.wang@...el.com>
To: Matthew Wilcox <willy@...radead.org>
CC: virtio-dev@...ts.oasis-open.org, linux-kernel@...r.kernel.org,
qemu-devel@...gnu.org, virtualization@...ts.linux-foundation.org,
kvm@...r.kernel.org, linux-mm@...ck.org, mst@...hat.com,
mhocko@...nel.org, akpm@...ux-foundation.org,
mawilcox@...rosoft.com, penguin-kernel@...ove.SAKURA.ne.jp
Subject: Re: [PATCH v20 3/7 RESEND] xbitmap: add more operations
On 01/02/2018 10:09 PM, Matthew Wilcox wrote:
> On Fri, Dec 22, 2017 at 04:49:11PM +0800, Wei Wang wrote:
>> Thanks for the improvement. I also found a small bug in xb_zero. With the
>> following changes, it has passed the current test cases and tested with the
>> virtio-balloon usage without any issue.
> Thanks; I applied the change. Can you supply a test-case for testing
> xb_zero please?
>
Sure. Please check below the test cases. Do you plan to send out the new
version of xbitmap yourself? If so, I will wait for that to send out the
virtio-balloon patches.
static void xbitmap_check_zero_bits(void)
{
assert(xb_empty(&xb1));
/* Zero an empty xbitmap should work though no real work to do */
xb_zero(&xb1, 0, ULONG_MAX);
assert(xb_empty(&xb1));
xb_preload(GFP_KERNEL);
assert(xb_set_bit(&xb1, 0) == 0);
xb_preload_end();
/* Overflow test */
xb_zero(&xb1, ULONG_MAX - 10, ULONG_MAX);
assert(xb_test_bit(&xb1, 0));
xb_preload(GFP_KERNEL);
assert(xb_set_bit(&xb1, ULONG_MAX) == 0);
xb_preload_end();
xb_zero(&xb1, 0, ULONG_MAX);
assert(xb_empty(&xb1));
}
/*
* In the following tests, preload is called once when all the bits to set
* locate in the same ida bitmap. Otherwise, it is recommended to call
* preload for each xb_set_bit.
*/
static void xbitmap_check_bit_range(void)
{
unsigned long nbit = 0;
/* Regular test1: node = NULL */
xb_preload(GFP_KERNEL);
xb_set_bit(&xb1, 700);
xb_preload_end();
assert(xb_find_set(&xb1, ULONG_MAX, &nbit) == true);
assert(nbit == 700);
nbit++;
assert(xb_find_set(&xb1, ULONG_MAX, &nbit) == false);
assert(nbit == 701);
xb_zero(&xb1, 0, 1023);
/*
* Regular test2
* set bit 2000, 2001, 2040
* Next 1 in [0, 2048] --> 2000
* Next 1 in [2000, 2002] --> 2000
* Next 1 in [2002, 2040] --> 2040
* Next 1 in [2002, 2039] --> none
* Next 0 in [2000, 2048] --> 2002
* Next 0 in [2048, 2060] --> 2048
*/
xb_preload(GFP_KERNEL);
assert(!xb_set_bit(&xb1, 2000));
assert(!xb_set_bit(&xb1, 2001));
assert(!xb_set_bit(&xb1, 2040));
nbit = 0;
assert(xb_find_set(&xb1, 2048, &nbit) == true);
assert(nbit == 2000);
assert(xb_find_set(&xb1, 2002, &nbit) == true);
assert(nbit == 2000);
nbit = 2002;
assert(xb_find_set(&xb1, 2040, &nbit) == true);
assert(nbit == 2040);
nbit = 2002;
assert(xb_find_set(&xb1, 2039, &nbit) == false);
assert(nbit == 2002);
nbit = 2000;
assert(xb_find_zero(&xb1, 2048, &nbit) == true);
assert(nbit == 2002);
nbit = 2048;
assert(xb_find_zero(&xb1, 2060, &nbit) == true);
assert(nbit == 2048);
xb_zero(&xb1, 0, 2048);
nbit = 0;
assert(xb_find_set(&xb1, 2048, &nbit) == false);
assert(nbit == 0);
xb_preload_end();
/*
* Overflow tests:
* Set bit 1 and ULONG_MAX - 4
* Next 1 in [0, ULONG_MAX] --> 1
* Next 1 in [1, ULONG_MAX] --> 1
* Next 1 in [2, ULONG_MAX] --> ULONG_MAX - 4
* Next 1 in [ULONG_MAX - 3, 2] --> none
* Next 0 in [ULONG_MAX - 4, ULONG_MAX] --> ULONG_MAX - 3
* Zero [ULONG_MAX - 4, ULONG_MAX]
* Next 1 in [ULONG_MAX - 10, ULONG_MAX] --> none
* Next 1 in [ULONG_MAX - 1, 2] --> none
* Zero [0, 1]
* Next 1 in [0, 2] --> none
*/
xb_preload(GFP_KERNEL);
assert(!xb_set_bit(&xb1, 1));
xb_preload_end();
xb_preload(GFP_KERNEL);
assert(!xb_set_bit(&xb1, ULONG_MAX - 4));
nbit = 0;
assert(xb_find_set(&xb1, ULONG_MAX, &nbit) == true);
assert(nbit == 1);
nbit = 1;
assert(xb_find_set(&xb1, ULONG_MAX, &nbit) == true);
assert(nbit == 1);
nbit = 2;
assert(xb_find_set(&xb1, ULONG_MAX, &nbit) == true);
assert(nbit == ULONG_MAX - 4);
nbit++;
assert(xb_find_set(&xb1, 2, &nbit) == false);
assert(nbit == ULONG_MAX - 3);
nbit--;
assert(xb_find_zero(&xb1, ULONG_MAX, &nbit) == true);
assert(nbit == ULONG_MAX - 3);
xb_zero(&xb1, ULONG_MAX - 4, ULONG_MAX);
nbit = ULONG_MAX - 10;
assert(xb_find_set(&xb1, ULONG_MAX, &nbit) == false);
assert(nbit == ULONG_MAX - 10);
nbit = ULONG_MAX - 1;
assert(xb_find_set(&xb1, 2, &nbit) == false);
xb_zero(&xb1, 0, 1);
nbit = 0;
assert(xb_find_set(&xb1, 2, &nbit) == false);
assert(nbit == 0);
xb_preload_end();
assert(xb_empty(&xb1));
}
Best,
Wei
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