[f2fs-dev] [PATCH v2] f2fs: continuous counting for 'issued' in __issue_discard_cmd_orderly()

[f2fs-dev] [PATCH v2] f2fs: continuous counting for 'issued' in __issue_discard_cmd_orderly()

[Yuwei Guan]

As the 'dcc->discard_granularity' and 'dcc->max_ordered_discard' can be set
at the user space, and if the 'dcc->max_ordered_discard' is set larger than
'dcc->discard_granularity' in DPOLICY_BG mode, or it's a volume device,
discard_granularity can be tuned to 1 in f2fs_tuning_parameters(),
it will may send more requests than the number of 'dpolicy->max_requests'
in issue_discard_thread().

This patch will fix the issue.

Signed-off-by: Yuwei Guan <Yuwei.Guan@zeekrlife.com>
---
 fs/f2fs/segment.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index a9099a754dd2..908b9a9bd82d 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1379,8 +1379,8 @@ static void __queue_discard_cmd(struct f2fs_sb_info *sbi,
 	mutex_unlock(&SM_I(sbi)->dcc_info->cmd_lock);
 }
 
-static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
-					struct discard_policy *dpolicy)
+static void __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
+					struct discard_policy *dpolicy, int *issued)
 {
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
 	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
@@ -1388,7 +1388,6 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
 	struct discard_cmd *dc;
 	struct blk_plug plug;
 	unsigned int pos = dcc->next_pos;
-	unsigned int issued = 0;
 	bool io_interrupted = false;
 
 	mutex_lock(&dcc->cmd_lock);
@@ -1415,9 +1414,9 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
 		}
 
 		dcc->next_pos = dc->lstart + dc->len;
-		err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
+		err = __submit_discard_cmd(sbi, dpolicy, dc, issued);
 
-		if (issued >= dpolicy->max_requests)
+		if (*issued >= dpolicy->max_requests)
 			break;
 next:
 		node = rb_next(&dc->rb_node);
@@ -1433,10 +1432,8 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
 
 	mutex_unlock(&dcc->cmd_lock);
 
-	if (!issued && io_interrupted)
-		issued = -1;
-
-	return issued;
+	if (!(*issued) && io_interrupted)
+		*issued = -1;
 }
 static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
 					struct discard_policy *dpolicy);
@@ -1464,8 +1461,10 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
 		if (i + 1 < dpolicy->granularity)
 			break;
 
-		if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered)
-			return __issue_discard_cmd_orderly(sbi, dpolicy);
+		if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered) {
+			__issue_discard_cmd_orderly(sbi, dpolicy, &issued);
+			return issued;
+		}
 
 		pend_list = &dcc->pend_list[i];
 
-- 
2.34.1



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Re: [f2fs-dev] [PATCH v2] f2fs: continuous counting for 'issued' in __issue_discard_cmd_orderly()

[Yuwei Guan]

Bagas Sanjaya <bagasdotme@gmail.com> 于2022年12月11日周日 21:20写道：
>
> On Sun, Dec 11, 2022 at 08:18:52PM +0800, Yuwei Guan wrote:
> > As the 'dcc->discard_granularity' and 'dcc->max_ordered_discard' can be set
> > at the user space, and if the 'dcc->max_ordered_discard' is set larger than
> > 'dcc->discard_granularity' in DPOLICY_BG mode, or it's a volume device,
> > discard_granularity can be tuned to 1 in f2fs_tuning_parameters(),
> > it will may send more requests than the number of 'dpolicy->max_requests'
> > in issue_discard_thread().
> >
>
> You don't know how to stop sentences (aka "abusing" comma), so I read
> above as uber-long sentence. Care to reword? There are many cases when I
> have to reply with such rewording, but this time I choose not to do
> because I'm lazy at the time I write this reply.
>
Hi Bagas,
Thanks for your review.
Sorry for submitting a poorly described patch,
I will update a v3 patch to rewrite the issue description and solution.
> > This patch will fix the issue.
>
> Fix by what? I don't understand the code.
>
> >
> > Signed-off-by: Yuwei Guan <Yuwei.Guan@zeekrlife.com>
>
> You send from your Gmail address but have SoB from either personal email
> domain or is this a random company? If it is the latter, please talk
> with your company to fix the mail system so that you can send from its
> domain (and receive traffic from mailing lists). In any case, your email
> address in From header and SoB must match.
>
The email system has been fixed,
and the email addresses will match in the future.
> Thanks.
>
> --
> An old man doll... just what I always wanted! - Clara


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