On Mon, Jan 11, 2021 at 12:59 PM Sudarshan Rajagopalan
<sudaraja@xxxxxxxxxxxxxx> wrote:
>
> When performing memory reclaim support treating anonymous and
> file backed pages equally.
> Swapping anonymous pages out to memory can be efficient enough
> to justify treating anonymous and file backed pages equally.
>
> Signed-off-by: Sudarshan Rajagopalan <sudaraja@xxxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
> mm/vmscan.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 257cba79a96d..ec7585e0d5f5 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -169,6 +169,8 @@ struct scan_control {
> */
> int vm_swappiness = 60;
>
> +bool balance_anon_file_reclaim = false;
I think the same effect could be achieved by adjusting swappiness. The
"swappiness" can go to 200 now.
Please check the document at Documentation/admin-guide/sysctl/vm.rst, it says:
This control is used to define the rough relative IO cost of swapping
and filesystem paging, as a value between 0 and 200. At 100, the VM
assumes equal IO cost and will thus apply memory pressure to the page
cache and swap-backed pages equally; lower values signify more
expensive swap IO, higher values indicates cheaper.
> +
> static void set_task_reclaim_state(struct task_struct *task,
> struct reclaim_state *rs)
> {
> @@ -201,6 +203,13 @@ static DECLARE_RWSEM(shrinker_rwsem);
> static DEFINE_IDR(shrinker_idr);
> static int shrinker_nr_max;
>
> +static int __init cmdline_parse_balance_reclaim(char *p)
> +{
> + balance_anon_file_reclaim = true;
> + return 0;
> +}
> +early_param("balance_reclaim", cmdline_parse_balance_reclaim);
> +
> static int prealloc_memcg_shrinker(struct shrinker *shrinker)
> {
> int id, ret = -ENOMEM;
> @@ -2291,9 +2300,11 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
>
> /*
> * If there is enough inactive page cache, we do not reclaim
> - * anything from the anonymous working right now.
> + * anything from the anonymous working right now. But when balancing
> + * anon and page cache files for reclaim, allow swapping of anon pages
> + * even if there are a number of inactive file cache pages.
> */
> - if (sc->cache_trim_mode) {
> + if (!balance_anon_file_reclaim && sc->cache_trim_mode) {
> scan_balance = SCAN_FILE;
> goto out;
> }
> --
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> a Linux Foundation Collaborative Project
>
>
