From: Helge Deller <deller@gmx•de>
To: Eric Dumazet <eric.dumazet@gmail•com>,
linux-parisc@vger•kernel.org,
James Bottomley <James.Bottomley@HansenPartnership•com>,
John David Anglin <dave.anglin@bell•net>
Cc: Tom Herbert <therbert@google•com>,
"David S. Miller" <davem@davemloft•net>,
netdev@vger•kernel.org
Subject: Re: CONFIG_XPS depends on L1_CACHE_BYTES being greater than sizeof(struct xps_map)
Date: Fri, 23 Oct 2015 23:09:42 +0200 [thread overview]
Message-ID: <562AA216.5030107@gmx.de> (raw)
In-Reply-To: <20151023210810.GA1969@ls3530.box>
On 23.10.2015 23:08, Helge Deller wrote:
> * Eric Dumazet <eric.dumazet@gmail•com>:
>> On Fri, 2015-10-23 at 21:25 +0200, Helge Deller wrote:
>>
>>> Then, how about simply changing it to twice of L1_CACHE_BYTES ?
>>>
>>> #define XPS_MIN_MAP_ALLOC ((L1_CACHE_BYTES * 2 - sizeof(struct xps_map)) / sizeof(u16))
>>
>>
>> Seems good to me.
>
> Great!
>
> Can you then maybe give me an Acked-by or signed-off for the patch below?
> It further adds a compile-time check to avoid that XPS_MIN_MAP_ALLOC
> gets calculated to zero on any architecture - otherwise no queues would
> be allocated.
>
> In addition I would like to push it for v4.3 then through my parisc-tree
> (after keeping it in for-next for 1-2 days), together with the patch
> which reduces L1_CACHE_BYTES to 16 on parisc.
> Would that be OK too?
>
> Thanks!
> Helge
>
>
> [PATCH] net/xps: Increase initial number of xps queues
>
> Increase the number of initial allocated xps queues, so that the initial record
> allocates twice the size of L1_CACHE_BYTES bytes.
>
> This change is needed to copy with architectures where L1_CACHE_BYTES is
s/copy/cope/g
> defined to equal or less than 16 bytes.
>
> Signed-off-by: Helge Deller <deller@gmx•de>
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 2d15e38..d152788 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -718,7 +718,7 @@ struct xps_map {
> u16 queues[0];
> };
> #define XPS_MAP_SIZE(_num) (sizeof(struct xps_map) + ((_num) * sizeof(u16)))
> -#define XPS_MIN_MAP_ALLOC ((L1_CACHE_BYTES - sizeof(struct xps_map)) \
> +#define XPS_MIN_MAP_ALLOC ((L1_CACHE_BYTES * 2 - sizeof(struct xps_map)) \
> / sizeof(u16))
>
> /*
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 6bb6470..f6d6dd1 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -1972,6 +1972,8 @@ static struct xps_map *expand_xps_map(struct xps_map *map,
> int alloc_len = XPS_MIN_MAP_ALLOC;
> int i, pos;
>
> + BUILD_BUG_ON(XPS_MIN_MAP_ALLOC == 0);
> +
> for (pos = 0; map && pos < map->len; pos++) {
> if (map->queues[pos] != index)
> continue;
>
next prev parent reply other threads:[~2015-10-23 21:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <42430464-867C-4E0B-8E95-C6CDB6D8A0B2@bell.net>
[not found] ` <32A3BF6F-B243-4AD4-9AE9-A5F9DAE0270A@bell.net>
[not found] ` <B8E85737-5ECD-4CBE-8730-886B098C5FA4@bell.net>
[not found] ` <trinity-eda7d55d-7234-4b29-a15c-955f8ba0c95e-1445513884942@3capp-gmx-bs32>
[not found] ` <trinity-8980ad10-b889-45cf-8f37-a33ba9cf99ef-1445514797080@3capp-gmx-bs32>
[not found] ` <1445524549.2207.1.camel@HansenPartnership.com>
[not found] ` <5628F868.3040105@bell.net>
2015-10-22 20:00 ` CONFIG_XPS depends on L1_CACHE_BYTES being greater than sizeof(struct xps_map) Helge Deller
2015-10-22 21:37 ` Tom Herbert
2015-10-23 19:21 ` Helge Deller
2015-10-23 22:16 ` Tom Herbert
2015-10-22 21:50 ` Eric Dumazet
2015-10-23 19:25 ` Helge Deller
2015-10-23 20:03 ` Eric Dumazet
2015-10-23 21:08 ` Helge Deller
2015-10-23 21:09 ` Helge Deller [this message]
2015-10-23 21:38 ` Eric Dumazet
2015-10-23 22:00 ` Alexander Duyck
2015-10-23 22:17 ` Helge Deller
2015-10-23 22:40 ` Alexander Duyck
2015-10-24 14:43 ` Helge Deller
2015-10-25 5:41 ` Alexander Duyck
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