Messages in this thread | | | From | Xin Hao <> | Subject | Re: [PATCH 02/11] mm/damon/dbgfs: Remove an unnecessary error message | Date | Wed, 8 Dec 2021 23:13:34 +0800 |
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Hi SeongJae:
On 12/8/21 8:49 PM, SeongJae Park wrote: > On Wed, 8 Dec 2021 14:29:40 +0800 Xin Hao <xhao@linux.alibaba.com> wrote: > > Hi Xin, > >> Hi park: >> >> On 12/1/21 11:04 PM, SeongJae Park wrote: >>> When wrong scheme action is requested via the debugfs interface, DAMON >>> prints an error message. Because the function returns error code, this >>> is not really needed. Because the code path is triggered by the user >>> specified input, this can result in kernel log mistakenly being messy. >> Completely correct, but there will also be a problem that users can’t >> quickly locate where the problem is, >> >> Especially too many parameters need to be written into the interface. >> >> I think it is necessary to add some debugging methods to help users find >> the error without polluting the kernel log. >> >> And i have an idea, like this: >> >> in dbgfs, add a last_cmd_stat interface. >> >> # echo "1 2 1 2 1 2 1 2 1 2 100 ..." > schemes >> >> # cat last_cmd_stat >> >> # wrong action 100 >> >> In this way, on the one hand, it will not pollute the kernel log, on the >> other hand, it will help users find the cause of the operation >> interface error. >> >> Park, how do you think of about this idea, if ok, i will send a patch. > Thank you always for your great suggestions and efforts! BTW, I prefer to be > called with my first name ;) Ha-Ha, Sorry! > > I want DAMON kernel code to be as simple and small as possible, while putting > fancy but complicated features for user conveniences in user space tools like > DAMO[1]. In other words, I hope the DAMON debugfs interface to be used as an > interface for such user space tools, not an interface for human hands. Ok, I know what you mean. > > IMHO, implementing the feature you proposed in the kernel could make the code > slightly bigger, while it can easily implemented in user space. I therefore > think the feature would be better to be implemented in user space. If you > could send a pull request of the feature for DAMO, it would be so great.
Ok, i will do it, But there's a problem here, If the user does not use the DAMO tools to operate the dbgfs interface,
the operation interface error will still hard to find the cause of errors.
> > [1] https://github.com/awslabs/damo > > > Thanks, > SJ > >>> To avoid the case, this commit removes the message >>> >>> Fixes: af122dd8f3c0 ("mm/damon/dbgfs: support DAMON-based Operation Schemes") >>> Signed-off-by: SeongJae Park <sj@kernel.org> >>> --- >>> mm/damon/dbgfs.c | 4 +--- >>> 1 file changed, 1 insertion(+), 3 deletions(-) >>> >>> diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c >>> index 4bf4204444ab..5b628990ae6e 100644 >>> --- a/mm/damon/dbgfs.c >>> +++ b/mm/damon/dbgfs.c >>> @@ -210,10 +210,8 @@ static struct damos **str_to_schemes(const char *str, ssize_t len, >>> &wmarks.low, &parsed); >>> if (ret != 18) >>> break; >>> - if (!damos_action_valid(action)) { >>> - pr_err("wrong action %d\n", action); >>> + if (!damos_action_valid(action)) >>> goto fail; >>> - } >>> >>> if (min_sz > max_sz || min_nr_a > max_nr_a || min_age > max_age) >>> goto fail; >> -- >> Best Regards! >> Xin Hao >> -- Best Regards! Xin Hao
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