linux-stable/lib/dim/rdma_dim.c
Gustavo A. R. Silva 6a9dc5fd61 lib: Revert use of fallthrough pseudo-keyword in lib/
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 <natechancellor@gmail.com>
Fixes: df561f6688 ("treewide: Use fallthrough pseudo-keyword")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-and-tested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-24 14:17:44 -07:00

108 lines
2.6 KiB
C

// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
/*
* Copyright (c) 2019, Mellanox Technologies inc. All rights reserved.
*/
#include <linux/dim.h>
static int rdma_dim_step(struct dim *dim)
{
if (dim->tune_state == DIM_GOING_RIGHT) {
if (dim->profile_ix == (RDMA_DIM_PARAMS_NUM_PROFILES - 1))
return DIM_ON_EDGE;
dim->profile_ix++;
dim->steps_right++;
}
if (dim->tune_state == DIM_GOING_LEFT) {
if (dim->profile_ix == 0)
return DIM_ON_EDGE;
dim->profile_ix--;
dim->steps_left++;
}
return DIM_STEPPED;
}
static int rdma_dim_stats_compare(struct dim_stats *curr,
struct dim_stats *prev)
{
/* first stat */
if (!prev->cpms)
return DIM_STATS_SAME;
if (IS_SIGNIFICANT_DIFF(curr->cpms, prev->cpms))
return (curr->cpms > prev->cpms) ? DIM_STATS_BETTER :
DIM_STATS_WORSE;
if (IS_SIGNIFICANT_DIFF(curr->cpe_ratio, prev->cpe_ratio))
return (curr->cpe_ratio > prev->cpe_ratio) ? DIM_STATS_BETTER :
DIM_STATS_WORSE;
return DIM_STATS_SAME;
}
static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim)
{
int prev_ix = dim->profile_ix;
u8 state = dim->tune_state;
int stats_res;
int step_res;
if (state != DIM_PARKING_ON_TOP && state != DIM_PARKING_TIRED) {
stats_res = rdma_dim_stats_compare(curr_stats,
&dim->prev_stats);
switch (stats_res) {
case DIM_STATS_SAME:
if (curr_stats->cpe_ratio <= 50 * prev_ix)
dim->profile_ix = 0;
break;
case DIM_STATS_WORSE:
dim_turn(dim);
/* fall through */
case DIM_STATS_BETTER:
step_res = rdma_dim_step(dim);
if (step_res == DIM_ON_EDGE)
dim_turn(dim);
break;
}
}
dim->prev_stats = *curr_stats;
return dim->profile_ix != prev_ix;
}
void rdma_dim(struct dim *dim, u64 completions)
{
struct dim_sample *curr_sample = &dim->measuring_sample;
struct dim_stats curr_stats;
u32 nevents;
dim_update_sample_with_comps(curr_sample->event_ctr + 1, 0, 0,
curr_sample->comp_ctr + completions,
&dim->measuring_sample);
switch (dim->state) {
case DIM_MEASURE_IN_PROGRESS:
nevents = curr_sample->event_ctr - dim->start_sample.event_ctr;
if (nevents < DIM_NEVENTS)
break;
dim_calc_stats(&dim->start_sample, curr_sample, &curr_stats);
if (rdma_dim_decision(&curr_stats, dim)) {
dim->state = DIM_APPLY_NEW_PROFILE;
schedule_work(&dim->work);
break;
}
/* fall through */
case DIM_START_MEASURE:
dim->state = DIM_MEASURE_IN_PROGRESS;
dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0,
curr_sample->comp_ctr,
&dim->start_sample);
break;
case DIM_APPLY_NEW_PROFILE:
break;
}
}
EXPORT_SYMBOL(rdma_dim);