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Message-ID: <ZEviO+NPFP/IoiO2@chq-MS-7D45>
Date: Fri, 28 Apr 2023 23:11:55 +0800
From: Cai Huoqing <cai.huoqing@...ux.dev>
To: Herbert Xu <herbert@...dor.apana.org.au>
Cc: kuba@...nel.org, davem@...emloft.net, edumazet@...gle.com,
pabeni@...hat.com, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] netdevsim: fib: Make use of rhashtable_iter
On 26 4月 23 17:37:49, Herbert Xu wrote:
> Cai Huoqing <cai.huoqing@...ux.dev> wrote:
> > Iterating 'fib_rt_ht' by rhashtable_walk_next and rhashtable_iter directly
> > instead of using list_for_each, because each entry of fib_rt_ht can be
> > found by rhashtable API. And remove fib_rt_list.
> >
> > Signed-off-by: Cai Huoqing <cai.huoqing@...ux.dev>
> > ---
> > drivers/net/netdevsim/fib.c | 37 ++++++++++++++++++-------------------
> > 1 file changed, 18 insertions(+), 19 deletions(-)
>
> What is the rationale for this patch? Are you trying to save
> memory?
Hi
Thanks for your reply,
I think not need to use two structs to link fib_rt node,
fib_rt_list is redundant.
Thanks,
Cai-
>
> > @@ -1099,9 +1090,12 @@ static void nsim_fib_dump_inconsistent(struct notifier_block *nb)
> > /* The notifier block is still not registered, so we do not need to
> > * take any locks here.
> > */
> > - list_for_each_entry_safe(fib_rt, fib_rt_tmp, &data->fib_rt_list, list) {
> > - rhashtable_remove_fast(&data->fib_rt_ht, &fib_rt->ht_node,
> > + rhashtable_walk_enter(&data->fib_rt_ht, &hti);
> > + rhashtable_walk_start(&hti);
> > + while ((pos = rhashtable_walk_next(&hti))) {
> > + rhashtable_remove_fast(&data->fib_rt_ht, hti.p,
> > nsim_fib_rt_ht_params);
> > + fib_rt = rhashtable_walk_peek(&hti);
> > nsim_fib_rt_free(fib_rt, data);
> > }
>
> In general rhashtable walks are not stable. You may miss entries
> or see entries twice. They should be avoided unless absolutely
> necessary.
Agree, but how about using rhashtable_free_and_destroy here
instead of rhashtable_walk_next in this patch.
>
> Cheers,
> --
> Email: Herbert Xu <herbert@...dor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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