Re: [PATCH v3] mm/page_reporting: Add page_reporting_delay_ms module parameter

[SJ Park]

On Mon, 27 Jul 2026 23:05:45 +0000 pratmal@xxxxxxxxxx wrote:

> From: Pratyush Mallick <pratmal@xxxxxxxxxx>
> 
> Currently, the free page reporting uses a hardcoded delay of
> (2 HZ) between reporting intervals. While this is a reasonable
> default, it lacks the flexibility to adapt to varying guest workloads.
> 
> A low delay allows aggressive memory reclamation, returning unused
> pages to the host as quickly as possible. However, during spiky
> allocation/free churn, this immediate reporting can lead to a severe
> performance penalty (nested page faults) as the guest re-allocates memory
> that the host has just unmapped. In these scenarios, there is benefit
> from increasing the delay to batch free pages over a longer window,
> absorbing the churn without hypercall and re-fault overhead.
> 
> This patch exposes the delay as a module parameter:
> /sys/module/page_reporting/parameters/page_reporting_delay_ms, measured
> in milliseconds and defaults to 2000ms.

Makes sense to me.

> 
> Signed-off-by: Pratyush Mallick <pratmal@xxxxxxxxxx>

Reviewed-by: SJ Park <sj@xxxxxxxxxx>


Thanks,
SJ

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