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| author | Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com> | 2016-09-28 00:24:24 -0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-01-19 20:17:22 +0100 |
| commit | 6e8210ad2585ba8292d91374e2d0750dd45773e9 (patch) | |
| tree | 1e935f2d01dd0ac511372254c942e518449dc029 /net/lapb/lapb_subr.c | |
| parent | ddf0c377bf8204848cec783b6dd3b5c809ed00cd (diff) | |
blk-mq: Always schedule hctx->next_cpu
commit c02ebfdddbafa9a6a0f52fbd715e6bfa229af9d3 upstream.
Commit 0e87e58bf60e ("blk-mq: improve warning for running a queue on the
wrong CPU") attempts to avoid triggering the WARN_ON in
__blk_mq_run_hw_queue when the expected CPU is dead. Problem is, in the
last batch execution before round robin, blk_mq_hctx_next_cpu can
schedule a dead CPU and also update next_cpu to the next alive CPU in
the mask, which will trigger the WARN_ON despite the previous
workaround.
The following patch fixes this scenario by always scheduling the value
in hctx->next_cpu. This changes the moment when we round-robin the CPU
running the hctx, but it really doesn't matter, since it still executes
BLK_MQ_CPU_WORK_BATCH times in a row before switching to another CPU.
Fixes: 0e87e58bf60e ("blk-mq: improve warning for running a queue on the wrong CPU")
Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/lapb/lapb_subr.c')
0 files changed, 0 insertions, 0 deletions