Re: [PATCH v5] f2fs: Add bggc_io_aware to adjust the priority of BG_GC when issuing IO

[Chao Yu <chao@kernel.org>]

On 8/8/2025 5:48 PM, Liao Yuanhong wrote:
> Currently, we have encountered some issues while testing ZUFS. In
> situations near the storage limit (e.g., 50GB remaining), and after
> simulating fragmentation by repeatedly writing and deleting data, we found
> that application installation and startup tests conducted after idling for
> a few minutes take significantly longer several times that of traditional
> UFS. Tracing the operations revealed that the majority of I/Os were issued
> by background GC, which blocks normal I/O operations.
> 
> Under normal circumstances, ZUFS indeed requires more background GC and
> employs a more aggressive GC strategy. However, I aim to find a way to
> minimize the impact on regular I/O operations under these near-limit
> conditions. To address this, I have introduced a bggc_io_aware feature,
> which controls the prioritization of background GC in the presence of I/Os.
> This switch can be adjusted at the framework level to implement different
> strategies. If set to AWARE_ALL_IO, all background GC operations will be
> skipped during active I/O issuance. The default option remains consistent
> with the current strategy, ensuring no change in behavior.
> 
> Signed-off-by: Liao Yuanhong <liaoyuanhong@vivo.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,