Re: [f2fs-dev] [PATCH] f2fs-tools: add write hint support

[Chao Yu <chao@kernel.org>]

On 2024/8/9 15:32, Daejun Park wrote:
> This patch enables support for write hints by segment type.

What about adding an option to enable this functionality? otherwise,
for a device which doesn't support whint feature, it will cause
overhead whenever calling fcntl() syscall.

[snip]

> @@ -1005,7 +1005,7 @@ int get_device_info(int i)
>   #endif
>   
>   	if (!c.sparse_mode) {
> -		if (dev->zoned_model == F2FS_ZONED_HM && c.func == FSCK)
> +		if (dev->zoned_model == F2FS_ZONED_HM)

Why do we need to change the condtion?

[snip]

> -int dev_write(void *buf, __u64 offset, size_t len)
> +static int __dev_write(void *buf, __u64 offset, size_t len, enum rw_hint whint)
>   {
> +	bool set_whint = whint != WRITE_LIFE_NONE;
> +	u64 hint = whint;
>   	int fd;
>   
> +	fd = __get_device_fd(&offset);
> +	if (fd < 0)
> +		return fd;
> +
> +	if (lseek(fd, (off_t)offset, SEEK_SET) < 0)
> +		return -1;
> +
> +	if (set_whint)
> +		fcntl(fd, F_SET_RW_HINT, &hint);

What about keeping last hint in fd, and update it once new hint is
not same to old one?

Thanks,


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