Messages in this thread Patch in this message | | | From | Dongli Zhang <> | Subject | [PATCH 1/1] vhost scsi: allocate vhost_scsi with GFP_NOWAIT to avoid delay | Date | Wed, 20 Jan 2021 21:03:28 -0800 |
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The size of 'struct vhost_scsi' is order-10 (~2.3MB). It may take long time delay by kzalloc() to compact memory pages when there is a lack of high-order pages. As a result, there is latency to create a VM (with vhost-scsi) or to hotadd vhost-scsi-based storage.
The prior commit 595cb754983d ("vhost/scsi: use vmalloc for order-10 allocation") prefers to fallback only when really needed, while this patch changes allocation to GFP_NOWAIT in order to avoid the delay caused by memory page compact.
Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Joe Jin <joe.jin@oracle.com> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> --- Another option is to rework by reducing the size of 'struct vhost_scsi', e.g., by replacing inline vhost_scsi.vqs with just memory pointers while each vhost_scsi.vqs[i] should be allocated separately. Please let me know if that option is better.
drivers/vhost/scsi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 4ce9f00ae10e..85eaa4e883f4 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -1814,7 +1814,7 @@ static int vhost_scsi_open(struct inode *inode, struct file *f) struct vhost_virtqueue **vqs; int r = -ENOMEM, i; - vs = kzalloc(sizeof(*vs), GFP_KERNEL | __GFP_NOWARN | __GFP_RETRY_MAYFAIL); + vs = kzalloc(sizeof(*vs), GFP_NOWAIT | __GFP_NOWARN); if (!vs) { vs = vzalloc(sizeof(*vs)); if (!vs) -- 2.17.1
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