| Message ID | 20240228040857.306483-1-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | blk-mq: don't change nr_hw_queues and nr_maps for kdump kernel | expand |
On Wed, Feb 28, 2024 at 12:08:57PM +0800, Ming Lei wrote: > For most of ARCHs, 'nr_cpus=1' is passed for kdump kernel, so > nr_hw_queues for each mapping is supposed to be 1 already. > > More importantly, this way may cause trouble for driver, because blk-mq and > driver see different queue mapping since driver should setup hardware > queue setting before calling into allocating blk-mq tagset. > > So not overriding nr_hw_queues and nr_maps for kdump kernel. Great to see this hack retired. Reviewed-by: Christoph Hellwig <hch@lst.de>
On Wed, 28 Feb 2024 12:08:57 +0800, Ming Lei wrote: > For most of ARCHs, 'nr_cpus=1' is passed for kdump kernel, so > nr_hw_queues for each mapping is supposed to be 1 already. > > More importantly, this way may cause trouble for driver, because blk-mq and > driver see different queue mapping since driver should setup hardware > queue setting before calling into allocating blk-mq tagset. > > [...] Applied, thanks! [1/1] blk-mq: don't change nr_hw_queues and nr_maps for kdump kernel commit: ec30b461f3d067bd322a6c3a6c5105746ed9bf14 Best regards,
diff --git a/block/blk-mq.c b/block/blk-mq.c index 6abb4ce46baa..be5f6380d46d 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -4391,7 +4391,7 @@ static void blk_mq_update_queue_map(struct blk_mq_tag_set *set) if (set->nr_maps == 1) set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues; - if (set->ops->map_queues && !is_kdump_kernel()) { + if (set->ops->map_queues) { int i; /* @@ -4490,14 +4490,12 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) /* * If a crashdump is active, then we are potentially in a very - * memory constrained environment. Limit us to 1 queue and - * 64 tags to prevent using too much memory. + * memory constrained environment. Limit us to 64 tags to prevent + * using too much memory. */ - if (is_kdump_kernel()) { - set->nr_hw_queues = 1; - set->nr_maps = 1; + if (is_kdump_kernel()) set->queue_depth = min(64U, set->queue_depth); - } + /* * There is no use for more h/w queues than cpus if we just have * a single map @@ -4527,7 +4525,7 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) GFP_KERNEL, set->numa_node); if (!set->map[i].mq_map) goto out_free_mq_map; - set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues; + set->map[i].nr_queues = set->nr_hw_queues; } blk_mq_update_queue_map(set);
For most of ARCHs, 'nr_cpus=1' is passed for kdump kernel, so nr_hw_queues for each mapping is supposed to be 1 already. More importantly, this way may cause trouble for driver, because blk-mq and driver see different queue mapping since driver should setup hardware queue setting before calling into allocating blk-mq tagset. So not overriding nr_hw_queues and nr_maps for kdump kernel. Cc: Wen Xiong <wenxiong@us.ibm.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-mq.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)