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Date:   Fri, 11 Nov 2022 16:50:40 +0000
From:   Wei Liu <wei.liu@kernel.org>
To:     Shradha Gupta <shradhagupta@linux.microsoft.com>
Cc:     linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Long Li <longli@microsoft.com>,
        Michael Kelley <mikelley@microsoft.com>
Subject: Re: [PATCH] hv_balloon: Fix committed value in post_status() if
 dynamic memory is disabled
Message-ID: <Y259YF07nSes6zlp@liuwe-devbox-debian-v2>
References: <1667544770-31377-1-git-send-email-shradhagupta@linux.microsoft.com>
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On Thu, Nov 03, 2022 at 11:52:50PM -0700, Shradha Gupta wrote:
> If Dynamic memory is disabled for VM, the committed value reported by the
> post_status() call by hv_balloon driver includes compute_balloon_floor().
> This is not needed if balloon_up operations or hot_add operations were
> never requested on the VM(or if Dynamic memory was disabled for the VM)
> 
> Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>

Can you put a Fixes: tag here?

You can use git-blame to find out the culprit.

Thanks,
Wei.

> ---
>  drivers/hv/hv_balloon.c | 22 +++++++++++++++++-----
>  1 file changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
> index fdf6decacf06..a6f5321d4a2e 100644
> --- a/drivers/hv/hv_balloon.c
> +++ b/drivers/hv/hv_balloon.c
> @@ -1129,11 +1129,23 @@ static unsigned long compute_balloon_floor(void)
>  
>  static unsigned long get_pages_committed(struct hv_dynmem_device *dm)
>  {
> -	return vm_memory_committed() +
> -		dm->num_pages_ballooned +
> -		(dm->num_pages_added > dm->num_pages_onlined ?
> -		 dm->num_pages_added - dm->num_pages_onlined : 0) +
> -		compute_balloon_floor();
> +	unsigned long pages_committed;
> +
> +	pages_committed = vm_memory_committed();
> +
> +	/*
> +	 * If no balloon_up or hot_add operation was performed do not add
> +	 * num_pages_ballooned, number of pages offline or
> +	 * compute_balloon_floor() to the pages_committed value
> +	 */
> +	if (dm->num_pages_ballooned || dm->num_pages_added) {
> +		pages_committed += dm->num_pages_ballooned +
> +			(dm->num_pages_added > dm->num_pages_onlined ?
> +			 dm->num_pages_added - dm->num_pages_onlined : 0) +
> +			 compute_balloon_floor();
> +	}
> +
> +	return pages_committed;
>  }
>  
>  /*
> -- 
> 2.37.2
>