Change the upper boundary of SMC-R's snd_buf and rcv_buf to 512MB

[PATCH net-next 1/2] net/smc: set rmb's SG_MAX_SINGLE_ALLOC limitation only when CONFIG_ARCH_NO_SG_CHAIN is defined

Posted by Guangguan Wang 1 year, 6 months ago

SG_MAX_SINGLE_ALLOC is used to limit maximum number of entries that
will be allocated in one piece of scatterlist. When the entries of
scatterlist exceeds SG_MAX_SINGLE_ALLOC, sg chain will be used. From
commit 7c703e54cc71 ("arch: switch the default on ARCH_HAS_SG_CHAIN"),
we can know that the macro CONFIG_ARCH_NO_SG_CHAIN is used to identify
whether sg chain is supported. So, SMC-R's rmb buffer should be limitted
by SG_MAX_SINGLE_ALLOC only when the macro CONFIG_ARCH_NO_SG_CHAIN is
defined.

Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
Co-developed-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Fixes: a3fe3d01bd0d ("net/smc: introduce sg-logic for RMBs")
---
 net/smc/smc_core.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index fafdb97adfad..acca3b1a068f 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -2015,7 +2015,6 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
  */
 static u8 smc_compress_bufsize(int size, bool is_smcd, bool is_rmb)
 {
-	const unsigned int max_scat = SG_MAX_SINGLE_ALLOC * PAGE_SIZE;
 	u8 compressed;
 
 	if (size <= SMC_BUF_MIN_SIZE)
@@ -2025,9 +2024,11 @@ static u8 smc_compress_bufsize(int size, bool is_smcd, bool is_rmb)
 	compressed = min_t(u8, ilog2(size) + 1,
 			   is_smcd ? SMCD_DMBE_SIZES : SMCR_RMBE_SIZES);
 
+#ifdef CONFIG_ARCH_NO_SG_CHAIN
 	if (!is_smcd && is_rmb)
 		/* RMBs are backed by & limited to max size of scatterlists */
-		compressed = min_t(u8, compressed, ilog2(max_scat >> 14));
+		compressed = min_t(u8, compressed, ilog2((SG_MAX_SINGLE_ALLOC * PAGE_SIZE) >> 14));
+#endif
 
 	return compressed;
 }
-- 
2.24.3 (Apple Git-128)

Re: [PATCH net-next 1/2] net/smc: set rmb's SG_MAX_SINGLE_ALLOC limitation only when CONFIG_ARCH_NO_SG_CHAIN is defined

Posted by Simon Horman 1 year, 6 months ago

On Tue, May 28, 2024 at 09:51:37PM +0800, Guangguan Wang wrote:
> SG_MAX_SINGLE_ALLOC is used to limit maximum number of entries that
> will be allocated in one piece of scatterlist. When the entries of
> scatterlist exceeds SG_MAX_SINGLE_ALLOC, sg chain will be used. From
> commit 7c703e54cc71 ("arch: switch the default on ARCH_HAS_SG_CHAIN"),
> we can know that the macro CONFIG_ARCH_NO_SG_CHAIN is used to identify
> whether sg chain is supported. So, SMC-R's rmb buffer should be limitted

Hi Guangguan Wang,

As it looks like there will be a v2:

In this patch: limitted -> limited
In patch 2/2:  defalut -> default

checkpatch.pl --codespell is your friend.

> by SG_MAX_SINGLE_ALLOC only when the macro CONFIG_ARCH_NO_SG_CHAIN is
> defined.
> 
> Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
> Co-developed-by: Wen Gu <guwen@linux.alibaba.com>
> Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
> Fixes: a3fe3d01bd0d ("net/smc: introduce sg-logic for RMBs")

I think it is usual to put the fixes tag above the Signed-of tags,
although I don't see anything about that in [1].

[1] https://www.kernel.org/doc/html/latest/process/submitting-patches.html#using-reported-by-tested-by-reviewed-by-suggested-by-and-fixes

...

Re: [PATCH net-next 1/2] net/smc: set rmb's SG_MAX_SINGLE_ALLOC limitation only when CONFIG_ARCH_NO_SG_CHAIN is defined

Posted by Guangguan Wang 1 year, 6 months ago


On 2024/6/1 16:35, Simon Horman wrote:
> On Tue, May 28, 2024 at 09:51:37PM +0800, Guangguan Wang wrote:
>> SG_MAX_SINGLE_ALLOC is used to limit maximum number of entries that
>> will be allocated in one piece of scatterlist. When the entries of
>> scatterlist exceeds SG_MAX_SINGLE_ALLOC, sg chain will be used. From
>> commit 7c703e54cc71 ("arch: switch the default on ARCH_HAS_SG_CHAIN"),
>> we can know that the macro CONFIG_ARCH_NO_SG_CHAIN is used to identify
>> whether sg chain is supported. So, SMC-R's rmb buffer should be limitted
> 
> Hi Guangguan Wang,
> 
> As it looks like there will be a v2:
> 
> In this patch: limitted -> limited
> In patch 2/2:  defalut -> default
> 
> checkpatch.pl --codespell is your friend.
> 
>> by SG_MAX_SINGLE_ALLOC only when the macro CONFIG_ARCH_NO_SG_CHAIN is
>> defined.
>>
>> Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
>> Co-developed-by: Wen Gu <guwen@linux.alibaba.com>
>> Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
>> Fixes: a3fe3d01bd0d ("net/smc: introduce sg-logic for RMBs")
> 
> I think it is usual to put the fixes tag above the Signed-of tags,
> although I don't see anything about that in [1].
> 
> [1] https://www.kernel.org/doc/html/latest/process/submitting-patches.html#using-reported-by-tested-by-reviewed-by-suggested-by-and-fixes
> 
> ...

I will fix it in the next version.

Thanks,
Guangguan Wang