Sahitya,
On 2021/3/15 12:56, Sahitya Tummala wrote:
> When f2fs is heavily utilized over 80%, the current discard policy
> sets the max sleep timeout of discard thread as 50ms
> (DEF_MIN_DISCARD_ISSUE_TIME). But this is set even when there are
> no pending discard commands to be issued. This results into
> unnecessary frequent and periodic wake ups of the discard thread.
> This patch adds check for pending discard commands in addition
> to heavy utilization condition to prevent those wake ups.
Could this commit fix your issue?
https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=43f8c47ea7d59c7b2270835f1d7c4618a1ea27b6
Thanks,
>
> Signed-off-by: Sahitya Tummala <[email protected]>
> ---
> fs/f2fs/segment.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index dced46c..df30220 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1112,6 +1112,8 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
> struct discard_policy *dpolicy,
> int discard_type, unsigned int granularity)
> {
> + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
> +
> /* common policy */
> dpolicy->type = discard_type;
> dpolicy->sync = true;
> @@ -1129,7 +1131,8 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
> dpolicy->io_aware = true;
> dpolicy->sync = false;
> dpolicy->ordered = true;
> - if (utilization(sbi) > DEF_DISCARD_URGENT_UTIL) {
> + if (utilization(sbi) > DEF_DISCARD_URGENT_UTIL &&
> + atomic_read(&dcc->discard_cmd_cnt)) {
> dpolicy->granularity = 1;
> dpolicy->max_interval = DEF_MIN_DISCARD_ISSUE_TIME;
> }
>