linux-toradex.git/lib/dim, branch v5.10-rc6

lib: Revert use of fallthrough pseudo-keyword in lib/

2020-08-24T21:17:44+00:00

The following build error for powerpc64 was reported by Nathan Chancellor:

  "$ scripts/config --file arch/powerpc/configs/powernv_defconfig -e KERNEL_XZ

   $ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64le-linux- distclean powernv_defconfig zImage
   ...
   In file included from arch/powerpc/boot/../../../lib/decompress_unxz.c:234,
                    from arch/powerpc/boot/decompress.c:38:
   arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c: In function 'dec_main':
   arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c:586:4: error: 'fallthrough' undeclared (first use in this function)
     586 |    fallthrough;
         |    ^~~~~~~~~~~

   This will end up affecting distribution configurations such as Debian
   and OpenSUSE according to my testing. I am not sure what the solution
   is, the PowerPC wrapper does not set -D__KERNEL__ so I am not sure
   that compiler_attributes.h can be safely included."

In order to avoid these sort of problems, it seems that the best
solution is to use /* fall through */ comments instead of the
fallthrough pseudo-keyword macro in lib/, for now.

Reported-by: Nathan Chancellor 
Fixes: df561f6688fe ("treewide: Use fallthrough pseudo-keyword")
Signed-off-by: Gustavo A. R. Silva 
Reviewed-and-tested-by: Nathan Chancellor 
Signed-off-by: Linus Torvalds

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

lib/dim: Fix -Wunused-const-variable warnings

2019-07-25T18:34:39+00:00

DIM causes to the following warnings during kernel compilation
which indicates that tx_profile and rx_profile are supposed to
be declared in *.c and not in *.h files.

In file included from ./include/rdma/ib_verbs.h:64,
                 from ./include/linux/mlx5/device.h:37,
                 from ./include/linux/mlx5/driver.h:51,
                 from ./include/linux/mlx5/vport.h:36,
                 from drivers/infiniband/hw/mlx5/ib_virt.c:34:
./include/linux/dim.h:326:1: warning: _tx_profile_ defined but not used [-Wunused-const-variable=]
  326 | tx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
      | ^~~~~~~~~~
./include/linux/dim.h:320:1: warning: _rx_profile_ defined but not used [-Wunused-const-variable=]
  320 | rx_profile[DIM_CQ_PERIOD_NUM_MODES][NET_DIM_PARAMS_NUM_PROFILES] = {
      | ^~~~~~~~~~

Fixes: 4f75da3666c0 ("linux/dim: Move implementation to .c files")
Signed-off-by: Leon Romanovsky 
Reviewed-by: Bart Van Assche 
Acked-by: Saeed Mahameed 
Signed-off-by: David S. Miller

linux/dim: Fix overflow in dim calculation

2019-07-25T18:34:39+00:00

While using net_dim, a dim_sample was used without ever initializing the
comps value. Added use of DIV_ROUND_DOWN_ULL() to prevent potential
overflow, it should not be a problem to save the final result in an int
because after the division by epms the value should not be larger than a
few thousand.

[ 1040.127124] UBSAN: Undefined behaviour in lib/dim/dim.c:78:23
[ 1040.130118] signed integer overflow:
[ 1040.131643] 134718714 * 100 cannot be represented in type 'int'

Fixes: 398c2b05bbee ("linux/dim: Add completions count to dim_sample")
Signed-off-by: Yamin Friedman 
Signed-off-by: Leon Romanovsky 
Acked-by: Saeed Mahameed 
Signed-off-by: David S. Miller

linux/dim: Implement RDMA adaptive moderation (DIM)

2019-07-08T19:37:21+00:00

RDMA DIM implements a different algorithm from net DIM and is based on
completions which is how we can implement interrupt moderation in RDMA.

The algorithm optimizes for number of completions and ratio between
completions and events. In order to avoid long latencies, the
implementation performs fast reduction of moderation level when the
traffic changes.

Signed-off-by: Yamin Friedman 
Reviewed-by: Max Gurtovoy 
Reviewed-by: Sagi Grimberg 
Signed-off-by: Saeed Mahameed 
Signed-off-by: Leon Romanovsky 
Signed-off-by: Jason Gunthorpe

linux/dim: Add completions count to dim_sample

2019-06-25T20:46:40+00:00

Added a measurement of completions per/msec to allow for completion based
dim algorithms.

In order to use dynamic interrupt moderation with RDMA we need to have a
different measurment than packets per second. This change is meant to
prepare for adding a new DIM method.

All drivers that use net_dim and thus do not need a completion count will
have the completions set to 0.

Signed-off-by: Yamin Friedman 
Reviewed-by: Max Gurtovoy 
Signed-off-by: Saeed Mahameed

linux/dim: Move implementation to .c files

2019-06-25T20:46:39+00:00

Moved all logic from dim.h and net_dim.h to dim.c and net_dim.c.
This is both more structurally appealing and would allow to only
expose externally used functions.

Signed-off-by: Tal Gilboa 
Signed-off-by: Saeed Mahameed