[PATCH v17 06/10] erofs: introduce the page cache share feature

[Gao Xiang]

On 2026/1/22 23:34, Hongbo Li wrote:
> From: Hongzhen Luo <hongzhen at linux.alibaba.com>
> 
> Currently, reading files with different paths (or names) but the same
> content will consume multiple copies of the page cache, even if the
> content of these page caches is the same. For example, reading
> identical files (e.g., *.so files) from two different minor versions of
> container images will cost multiple copies of the same page cache,
> since different containers have different mount points. Therefore,
> sharing the page cache for files with the same content can save memory.
> 
> This introduces the page cache share feature in erofs. It allocate a
> shared inode and use its page cache as shared. Reads for files
> with identical content will ultimately be routed to the page cache of
> the shared inode. In this way, a single page cache satisfies
> multiple read requests for different files with the same contents.
> 
> We introduce new mount option `inode_share` to enable the page
> sharing mode during mounting. This option is used in conjunction
> with `domain_id` to share the page cache within the same trusted
> domain.
> 
> Signed-off-by: Hongzhen Luo <hongzhen at linux.alibaba.com>
> Signed-off-by: Hongbo Li <lihongbo22 at huawei.com>

Reviewed-by: Gao Xiang <hsiangkao at linux.alibaba.com>

Thanks,
Gao Xiang