Re: [PATCH] ext4: Don't use CR_BEST_AVAIL_LEN for non-regular files

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sun, Jul 16, 2023 at 07:33:34PM +0530, Ritesh Harjani (IBM) wrote:
> Using CR_BEST_AVAIL_LEN only make sense for regular files, as for
> non-regular files we never normalize the allocation request length i.e.
> goal len is same as original length (ac_g_ex.fe_len == ac_o_ex.fe_len).
> 
> Hence there is no scope of trimming the goal length to make it
> satisfy original request len. Thus this patch avoids using
> CR_BEST_AVAIL_LEN criteria for non-regular files request.
> 
> Fixes: 33122aa930f1 ("ext4: Add allocation criteria 1.5 (CR1_5)")
> Reported-by: Eric Whitney <enwlinux@xxxxxxxxx>
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
> ---
Hi Ritesh,

patch looks good to me. Feel free to add:

Reviewed-by: Ojaswin Mujoo <ojaswin.linux.ibm.com>

Regards,
ojaswin
>  fs/ext4/mballoc.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 3ab37533349f..bc004f5d3f3c 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -975,7 +975,18 @@ static void ext4_mb_choose_next_group_goal_fast(struct ext4_allocation_context *
>  		*group = grp->bb_group;
>  		ac->ac_flags |= EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED;
>  	} else {
> -		*new_cr = CR_BEST_AVAIL_LEN;
> +		/*
> +		 * CR_BEST_AVAIL_LEN works based on the concept that we have
> +		 * a larger normalized goal len request which can be trimmed to
> +		 * a smaller goal len such that it can still satisfy original
> +		 * request len. However, allocation request for non-regular
> +		 * files never gets normalized.
> +		 * See function ext4_mb_normalize_request() (EXT4_MB_HINT_DATA).
> +		 */
> +		if (ac->ac_flags & EXT4_MB_HINT_DATA)
> +			*new_cr = CR_BEST_AVAIL_LEN;
> +		else
> +			*new_cr = CR_GOAL_LEN_SLOW;
>  	}
>  }
> 
> --
> 2.40.1
> 



[Index of Archives]     [Reiser Filesystem Development]     [Ceph FS]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux FS]     [Yosemite National Park]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Device Mapper]     [Linux Media]

  Powered by Linux