drivers/net/ethernet/chelsio/cxgb4/sge.c:2396:13: warning: stack frame size of 1168 bytes in function 'ethofld_xmit'
5:36 p.m.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 84196390620ac0e5070ae36af84c137c6216a7dc
commit: 97e4910232fa1f81e806aa60c25a0450276d99a2 linux/compiler-clang.h: define
HAVE_BUILTIN_BSWAP*
date: 9 days ago
config: mips-randconfig-r023-20210322 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project
78a65cd945d006ff02f9d24d9cc20a302ed93b08)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# install mips cross compiling tool for clang build
# apt-get install binutils-mips-linux-gnu
#
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit...
git remote add linus
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 97e4910232fa1f81e806aa60c25a0450276d99a2
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com>
All warnings (new ones prefixed by >>):
drivers/net/ethernet/chelsio/cxgb4/sge.c:814:28: warning: unused function
'calc_tx_descs' [-Wunused-function]
static inline unsigned int calc_tx_descs(const struct sk_buff *skb,
^
> drivers/net/ethernet/chelsio/cxgb4/sge.c:2396:13: warning: stack
frame size of 1168 bytes in function 'ethofld_xmit' [-Wframe-larger-than=]
static void ethofld_xmit(struct net_device *dev, struct sge_eosw_txq *eosw_txq)
^
2 warnings generated.
vim +/ethofld_xmit +2396 drivers/net/ethernet/chelsio/cxgb4/sge.c
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2395
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 @2396 static void ethofld_xmit(struct
net_device *dev, struct sge_eosw_txq *eosw_txq)
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2397 {
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2398 struct sk_buff *skb;
4f1d97262d58e0 Rahul Lakkireddy 2020-05-15 2399 int pktcount, ret;
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2400
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2401 switch (eosw_txq->state) {
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2402 case CXGB4_EO_STATE_ACTIVE:
0e395b3cb1fb82 Rahul Lakkireddy 2019-11-07 2403 case CXGB4_EO_STATE_FLOWC_OPEN_SEND:
0e395b3cb1fb82 Rahul Lakkireddy 2019-11-07 2404 case CXGB4_EO_STATE_FLOWC_CLOSE_SEND:
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2405 pktcount = eosw_txq->pidx -
eosw_txq->last_pidx;
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2406 if (pktcount < 0)
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2407 pktcount += eosw_txq->ndesc;
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2408 break;
0e395b3cb1fb82 Rahul Lakkireddy 2019-11-07 2409 case CXGB4_EO_STATE_FLOWC_OPEN_REPLY:
0e395b3cb1fb82 Rahul Lakkireddy 2019-11-07 2410 case CXGB4_EO_STATE_FLOWC_CLOSE_REPLY:
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2411 case CXGB4_EO_STATE_CLOSED:
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2412 default:
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2413 return;
272630feb4c0d2 Rahul Lakkireddy 2019-11-19 2414 }
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2415
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2416 while (pktcount--) {
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2417 skb = eosw_txq_peek(eosw_txq);
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2418 if (!skb) {
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2419
eosw_txq_advance_index(&eosw_txq->last_pidx, 1,
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2420 eosw_txq->ndesc);
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2421 continue;
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2422 }
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2423
4f1d97262d58e0 Rahul Lakkireddy 2020-05-15 2424 ret = ethofld_hard_xmit(dev,
eosw_txq);
4f1d97262d58e0 Rahul Lakkireddy 2020-05-15 2425 if (ret)
4f1d97262d58e0 Rahul Lakkireddy 2020-05-15 2426 break;
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2427 }
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2428 }
4846d5330dafc8 Rahul Lakkireddy 2019-11-07 2429
:::::: The code at line 2396 was first introduced by commit
:::::: 4846d5330dafc82990be7ffe1d1b383157268bd9 cxgb4: add Tx and Rx path for ETHOFLD
traffic
:::::: TO: Rahul Lakkireddy <rahul.lakkireddy(a)chelsio.com>
:::::: CC: David S. Miller <davem(a)davemloft.net>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
8:24 p.m.
On Tue, Mar 23, 2021 at 7:37 AM kernel test robot <lkp(a)intel.com> wrote:
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 84196390620ac0e5070ae36af84c137c6216a7dc
commit: 97e4910232fa1f81e806aa60c25a0450276d99a2 linux/compiler-clang.h: define
HAVE_BUILTIN_BSWAP*
date: 9 days ago
config: mips-randconfig-r023-20210322 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project
78a65cd945d006ff02f9d24d9cc20a302ed93b08)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# install mips cross compiling tool for clang build
# apt-get install binutils-mips-linux-gnu
#
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit...
git remote add linus
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 97e4910232fa1f81e806aa60c25a0450276d99a2
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com>
All warnings (new ones prefixed by >>):
drivers/net/ethernet/chelsio/cxgb4/sge.c:814:28: warning: unused function
'calc_tx_descs' [-Wunused-function]
static inline unsigned int calc_tx_descs(const struct sk_buff *skb,
^
>> drivers/net/ethernet/chelsio/cxgb4/sge.c:2396:13: warning: stack frame size of
1168 bytes in function 'ethofld_xmit' [-Wframe-larger-than=]
static void ethofld_xmit(struct net_device *dev, struct sge_eosw_txq *eosw_txq)
^
2 warnings generated.
This looks related to a warning we saw on powerpc. I've tried digging
into it a little
bit more, but all I found is that the use of __builtin_bswap32() changes the
inlining decisions but doesn't actively cause worse code.
In fact, if I force the inlining like this:
--- a/drivers/net/ethernet/chelsio/cxgb4/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c
@@ -2257,7 +2257,7 @@ static void *write_eo_wr(struct adapter *adap,
struct sge_eosw_txq *eosw_txq,
return cpl;
}
-static int ethofld_hard_xmit(struct net_device *dev,
+static __attribute__((flatten)) __always_inline int
ethofld_hard_xmit(struct net_device *dev,
struct sge_eosw_txq *eosw_txq)
{
struct port_info *pi = netdev2pinfo(dev);
@@ -2393,7 +2393,7 @@ static int ethofld_hard_xmit(struct net_device *dev,
return ret;
}
-static void ethofld_xmit(struct net_device *dev, struct sge_eosw_txq *eosw_txq)
+static noinline void ethofld_xmit(struct net_device *dev, struct
sge_eosw_txq *eosw_txq)
{
struct sk_buff *skb;
int pktcount, ret;
I see a different effect: the function's frame grows to 2232 bytes with the
open-coded bswap32 slightly less at 2200 bytes with the builtin bswap32,
all because of too many variables getting spilled.
On the other hand, marking ethofld_hard_xmit as flatten+noinline, I don't
get these spills with either version of bswap32, and the stack usage of
ethofld_hard_xmit()/ethofld_xmit() goes down to 472+112 bytes.
If I remove -fsanitize=alignment, the total stack size for these functions is
no more than 368 bytes regardless of the inlining or the bswap32()
implementation.
I would conclude that there is something wrong in clang that leads to badly
optimized code in this file, but that my __builtin_bswap32() change is only
what triggers the right conditions here, not the root cause.
Arnd
546
days inactive
546
days old
1 comments
2 participants
participants (2)
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Arnd Bergmann -
kernel test robot