Re: [PATCH v5] net/mlx5: Reclaim max 50K pages at once

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On 6/25/24 02:11, Jesse Brandeburg wrote:
On 6/24/2024 8:33 AM, Anand Khoje wrote:

--- a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
@@ -608,6 +608,7 @@ enum {
  	RELEASE_ALL_PAGES_MASK = 0x4000,
  };
+#define MAX_RECLAIM_NPAGES -50000
Can you please explain why this is negative? There doesn't seem to be
any reason mentioned in the commit message or code.

At the very least it's super confusing to have a MAX be negative, and at
worst it's a bug. I don't have any other context on this code besides
this patch, so an explanation would be helpful.



Hi Jesse,

The way Mellanox ConnectX5 driver handles 'release of allocated pages from HCA' or 'allocation of pages to HCA', is by sending an event to the host. This event will have number of pages in it. If the number is positive, that indicates HCA is requesting that number of pages to be allocated. And if that number is negative, it is the HCA indicating that that number of pages can be reclaimed by the host.

In this patch we are restricting the maximum number of pages that can be reclaimed to be 50000 (effectively this would be -50000 as it is reclaim). This limit is based on the capability of the firmware as it cannot release more than 50000 back to the host in one go.

I hope that explains.

Thanks,

Anand





[Index of Archives]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Photo]     [Yosemite News]     [Yosemite Photos]     [Linux Kernel]     [Linux SCSI]     [XFree86]

  Powered by Linux