All of lore.kernel.org
 help / color / mirror / Atom feed
From: Martin KaFai Lau <kafai@fb.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: <davem@davemloft.net>, <daniel@iogearbox.net>,
	<andrii@kernel.org>, <netdev@vger.kernel.org>,
	<bpf@vger.kernel.org>, <kernel-team@fb.com>
Subject: Re: [PATCH v4 bpf-next 2/9] bpf: Add map side support for bpf timers.
Date: Thu, 1 Jul 2021 23:23:43 -0700	[thread overview]
Message-ID: <20210702062343.dblrnycfwzjch6py@kafai-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20210701192044.78034-3-alexei.starovoitov@gmail.com>

On Thu, Jul 01, 2021 at 12:20:37PM -0700, Alexei Starovoitov wrote:
[ ... ]

> +static void htab_free_prealloced_timers(struct bpf_htab *htab)
> +{
> +	u32 num_entries = htab->map.max_entries;
> +	int i;
> +
> +	if (likely(!map_value_has_timer(&htab->map)))
> +		return;
> +	if (htab_has_extra_elems(htab))
> +		num_entries += num_possible_cpus();
> +
> +	for (i = 0; i < num_entries; i++) {
> +		struct htab_elem *elem;
> +
> +		elem = get_htab_elem(htab, i);
> +		bpf_timer_cancel_and_free(elem->key +
> +					  round_up(htab->map.key_size, 8) +
> +					  htab->map.timer_off);
> +		cond_resched();
> +	}
> +}
> +
[ ... ]

> +static void htab_free_malloced_timers(struct bpf_htab *htab)
> +{
> +	int i;
> +
> +	for (i = 0; i < htab->n_buckets; i++) {
> +		struct hlist_nulls_head *head = select_bucket(htab, i);
> +		struct hlist_nulls_node *n;
> +		struct htab_elem *l;
> +
> +		hlist_nulls_for_each_entry(l, n, head, hash_node)
It is called from map_release_uref() which is not under rcu.
Either a bucket lock or rcu_read_lock is needed here.

Another question, can prealloc map does the same thing
like here (i.e. walk the buckets) during map_release_uref()?

  reply	other threads:[~2021-07-02  6:24 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-01 19:20 [PATCH v4 bpf-next 0/9] bpf: Introduce BPF timers Alexei Starovoitov
2021-07-01 19:20 ` [PATCH v4 bpf-next 1/9] bpf: Introduce bpf timers Alexei Starovoitov
2021-07-02  1:04   ` Martin KaFai Lau
2021-07-04 14:19     ` Alexei Starovoitov
2021-07-07  1:38       ` Alexei Starovoitov
2021-07-06 13:57   ` luwei (O)
2021-07-06 15:44     ` Toke Høiland-Jørgensen
2021-07-01 19:20 ` [PATCH v4 bpf-next 2/9] bpf: Add map side support for " Alexei Starovoitov
2021-07-02  6:23   ` Martin KaFai Lau [this message]
2021-07-04 14:23     ` Alexei Starovoitov
2021-07-01 19:20 ` [PATCH v4 bpf-next 3/9] bpf: Prevent pointer mismatch in bpf_timer_init Alexei Starovoitov
2021-07-01 19:20 ` [PATCH v4 bpf-next 4/9] bpf: Remember BTF of inner maps Alexei Starovoitov
2021-07-01 19:20 ` [PATCH v4 bpf-next 5/9] bpf: Relax verifier recursion check Alexei Starovoitov
2021-07-01 19:20 ` [PATCH v4 bpf-next 6/9] bpf: Implement verifier support for validation of async callbacks Alexei Starovoitov
2021-07-01 19:20 ` [PATCH v4 bpf-next 7/9] bpf: Teach stack depth check about " Alexei Starovoitov
2021-07-01 19:20 ` [PATCH v4 bpf-next 8/9] selftests/bpf: Add bpf_timer test Alexei Starovoitov
2021-07-01 19:20 ` [PATCH v4 bpf-next 9/9] selftests/bpf: Add a test with bpf_timer in inner map Alexei Starovoitov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210702062343.dblrnycfwzjch6py@kafai-mbp.dhcp.thefacebook.com \
    --to=kafai@fb.com \
    --cc=alexei.starovoitov@gmail.com \
    --cc=andrii@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=davem@davemloft.net \
    --cc=kernel-team@fb.com \
    --cc=netdev@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.