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From: wangyunjian <wangyunjian@huawei.com>
To: "Burakov, Anatoly" <anatoly.burakov@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"david.marchand@redhat.com" <david.marchand@redhat.com>
Cc: "Lilijun (Jerry)" <jerry.lilijun@huawei.com>,
	xudingke <xudingke@huawei.com>,
	"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v2] eal/linux: do not create user mem map repeatedly when it exists
Date: Sat, 25 Jul 2020 09:59:12 +0000
Message-ID: <34EFBCA9F01B0748BEB6B629CE643AE60D0EAAD8@dggemm513-mbx.china.huawei.com> (raw)
In-Reply-To: <c35b31da-703e-d4d4-6283-0bb4e8ad57e2@intel.com>

> -----Original Message-----
> From: Burakov, Anatoly [mailto:anatoly.burakov@intel.com]
> Sent: Friday, July 24, 2020 9:25 PM
> To: wangyunjian <wangyunjian@huawei.com>; dev@dpdk.org;
> david.marchand@redhat.com
> Cc: Lilijun (Jerry) <jerry.lilijun@huawei.com>; xudingke
> <xudingke@huawei.com>; stable@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2] eal/linux: do not create user mem map
> repeatedly when it exists
> 
> On 23-Jul-20 3:48 PM, wangyunjian wrote:
> > From: Yunjian Wang <wangyunjian@huawei.com>
> >
> > Currently, we will create new user mem map entry for the same memory
> > segment, but in fact it has already been added to the user mem maps.
> > It's not necessary to create it twice.
> >
> > To resolve the issue, add support to remove the same entry in the
> > function compact_user_maps().
> >
> > Fixes: 0cbce3a167f1 ("vfio: skip DMA map failure if already mapped")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> > ---
> > v2:
> > * Remove the same entry in the function compact_user_maps()
> > ---
> >   lib/librte_eal/linux/eal_vfio.c | 5 +++++
> >   1 file changed, 5 insertions(+)
> >
> > diff --git a/lib/librte_eal/linux/eal_vfio.c b/lib/librte_eal/linux/eal_vfio.c
> > index abb12a354..df99307b7 100644
> > --- a/lib/librte_eal/linux/eal_vfio.c
> > +++ b/lib/librte_eal/linux/eal_vfio.c
> > @@ -167,6 +167,10 @@ adjust_map(struct user_mem_map *src, struct
> user_mem_map *end,
> >   static int
> >   merge_map(struct user_mem_map *left, struct user_mem_map *right)
> >   {
> > +	/* merge the same maps into one */
> > +	if (memcmp(left, right, sizeof(struct user_mem_map)) == 0)
> > +		goto out;
> > +
> 
> merge_map looks for adjacent maps only, but does not handle maps that
> are wholly contained within one another ("the same map" also matches
> this definition). wouldn't it be better to check for that instead of
> *just* handling identical maps?

What about using the initial implementation?
We don't create new user mem map entry for the same memory segment.

@@ -1828,6 +1828,13 @@  container_dma_map(struct vfio_config *vfio_cfg, uint64_t vaddr, uint64_t iova,
 		ret = -1;
 		goto out;
 	}
+
+	/* we don't need create new user mem map entry
+	 * for the same memory segment.
+	 */
+	if (errno == EBUSY || errno == EEXIST)
+		goto out;
+
 	/* create new user mem map entry */
 	new_map = &user_mem_maps->maps[user_mem_maps->n_maps++];
 	new_map->addr = vaddr;

Thanks,
Yunjian
> 
> >   	if (left->addr + left->len != right->addr)
> >   		return 0;
> >   	if (left->iova + left->len != right->iova)
> > @@ -174,6 +178,7 @@ merge_map(struct user_mem_map *left, struct
> user_mem_map *right)
> >
> >   	left->len += right->len;
> >
> > +out:
> >   	memset(right, 0, sizeof(*right));
> >
> >   	return 1;
> >
> 
> 
> --
> Thanks,
> Anatoly

  reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-16 13:38 [dpdk-dev] [PATCH 1/1] " wangyunjian
2020-07-17 14:19 ` Burakov, Anatoly
2020-07-17 14:23   ` Burakov, Anatoly
2020-07-20  2:00     ` wangyunjian
2020-07-20 11:46       ` Burakov, Anatoly
2020-07-22 12:47         ` wangyunjian
2020-07-23 14:48 ` [dpdk-dev] [PATCH v2] " wangyunjian
2020-07-24 13:25   ` Burakov, Anatoly
2020-07-25  9:59     ` wangyunjian [this message]
2020-07-27  9:24       ` Burakov, Anatoly
2020-07-30 13:16         ` wangyunjian
2020-07-31 11:55           ` Burakov, Anatoly
2020-08-05 12:58             ` wangyunjian
2020-09-17 11:33               ` Burakov, Anatoly
2020-09-17 11:35   ` Burakov, Anatoly

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