> -----Original Message----- > From: Guoqing Jiang <guoqing.jiang@xxxxxxxxx> > Sent: Tuesday, January 23, 2024 3:43 AM > To: Bernard Metzler <BMT@xxxxxxxxxxxxxx>; linux-rdma@xxxxxxxxxxxxxxx > Cc: jgg@xxxxxxxx; leon@xxxxxxxxxx; ionut_n2001@xxxxxxxxx > Subject: [EXTERNAL] Re: [PATCH] RDMA/siw: Trim size of page array to max > size needed > > Hi Bernard, > > On 1/19/24 21:05, Bernard Metzler wrote: > > siw tries sending all parts of an iWarp wire frame in one socket > > send operation. If user data can be send without copy, user data > > pages for one wire frame are referenced in an fixed size page array. > > The size of this array can be made 2 elements smaller, since it > > does not reference iWarp header and trailer crc. Trimming > > the page array reduces the affected siw_tx_hdt() functions frame > > size, staying below 1024 bytes. This avoids the following > > compile-time warning: > > > > drivers/infiniband/sw/siw/siw_qp_tx.c: In function 'siw_tx_hdt': > > drivers/infiniband/sw/siw/siw_qp_tx.c:677:1: warning: the frame > > size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=] > > I saw similar warning in my ubuntu 22.04 VM which has below gcc. > > root@buk:/home/gjiang/linux-mirror# make M=drivers/infiniband/sw/siw/ > -j16 W=1 > CC [M] drivers/infiniband/sw/siw/siw_qp_tx.o > drivers/infiniband/sw/siw/siw_qp_tx.c: In function ‘siw_tx_hdt’: > drivers/infiniband/sw/siw/siw_qp_tx.c:665:1: warning: the frame size of > 1440 bytes is larger than 1024 bytes [-Wframe-larger-than=] > 665 | } > | ^ > Whew.. that is quite substantially off the target! How come different compilers making so much of a difference. Guoqing, can you check if the macro computing the maximum number of fragments is broken, i.e., computes different values in the cases you refer? Thanks a lot! Bernard > # gcc --version > gcc (Ubuntu 12.3.0-1ubuntu1~22.04) 12.3.0 > > And it still appears after apply this patch on top of 6.8-rc1. > > root@buk:/home/gjiang/linux-mirror# git am > ./20240119_bmt_rdma_siw_trim_size_of_page_array_to_max_size_needed.mbx > Applying: RDMA/siw: Trim size of page array to max size needed > root@buk:/home/gjiang/linux-mirror# make M=drivers/infiniband/sw/siw/ > -j16 W=1 > CC [M] drivers/infiniband/sw/siw/siw_qp_tx.o > drivers/infiniband/sw/siw/siw_qp_tx.c: In function ‘siw_tx_hdt’: > drivers/infiniband/sw/siw/siw_qp_tx.c:668:1: warning: the frame size of > 1408 bytes is larger than 1024 bytes [-Wframe-larger-than=] > 668 | } > | ^ > > However with gcc-13.1, I can't see the warning with or without the > patch. > > Thanks, > Guoqing
