From: Greg Kurz <groug@kaod.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: <linux-fsdevel@vger.kernel.org>, <dan.j.williams@intel.com>,
<jack@suse.cz>, <willy@infradead.org>,
<linux-nvdimm@lists.01.org>, <miklos@szeredi.hu>,
<linux-kernel@vger.kernel.org>, <virtio-fs@redhat.com>
Subject: Re: [Virtio-fs] [PATCH v3 1/3] dax: Add an enum for specifying dax wakup mode
Date: Tue, 20 Apr 2021 09:19:25 +0200 [thread overview]
Message-ID: <20210420091925.08054e8b@bahia.lan> (raw)
In-Reply-To: <20210419213636.1514816-2-vgoyal@redhat.com>
On Mon, 19 Apr 2021 17:36:34 -0400
Vivek Goyal <vgoyal@redhat.com> wrote:
> Dan mentioned that he is not very fond of passing around a boolean true/false
> to specify if only next waiter should be woken up or all waiters should be
> woken up. He instead prefers that we introduce an enum and make it very
> explicity at the callsite itself. Easier to read code.
>
> This patch should not introduce any change of behavior.
>
> Suggested-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
> ---
Reviewed-by: Greg Kurz <groug@kaod.org>
> fs/dax.c | 23 +++++++++++++++++------
> 1 file changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index b3d27fdc6775..00978d0838b1 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -144,6 +144,16 @@ struct wait_exceptional_entry_queue {
> struct exceptional_entry_key key;
> };
>
> +/**
> + * enum dax_entry_wake_mode: waitqueue wakeup toggle
> + * @WAKE_NEXT: entry was not mutated
> + * @WAKE_ALL: entry was invalidated, or resized
> + */
> +enum dax_entry_wake_mode {
> + WAKE_NEXT,
> + WAKE_ALL,
> +};
> +
> static wait_queue_head_t *dax_entry_waitqueue(struct xa_state *xas,
> void *entry, struct exceptional_entry_key *key)
> {
> @@ -182,7 +192,8 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait,
> * The important information it's conveying is whether the entry at
> * this index used to be a PMD entry.
> */
> -static void dax_wake_entry(struct xa_state *xas, void *entry, bool wake_all)
> +static void dax_wake_entry(struct xa_state *xas, void *entry,
> + enum dax_entry_wake_mode mode)
> {
> struct exceptional_entry_key key;
> wait_queue_head_t *wq;
> @@ -196,7 +207,7 @@ static void dax_wake_entry(struct xa_state *xas, void *entry, bool wake_all)
> * must be in the waitqueue and the following check will see them.
> */
> if (waitqueue_active(wq))
> - __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key);
> + __wake_up(wq, TASK_NORMAL, mode == WAKE_ALL ? 0 : 1, &key);
> }
>
> /*
> @@ -268,7 +279,7 @@ static void put_unlocked_entry(struct xa_state *xas, void *entry)
> {
> /* If we were the only waiter woken, wake the next one */
> if (entry && !dax_is_conflict(entry))
> - dax_wake_entry(xas, entry, false);
> + dax_wake_entry(xas, entry, WAKE_NEXT);
> }
>
> /*
> @@ -286,7 +297,7 @@ static void dax_unlock_entry(struct xa_state *xas, void *entry)
> old = xas_store(xas, entry);
> xas_unlock_irq(xas);
> BUG_ON(!dax_is_locked(old));
> - dax_wake_entry(xas, entry, false);
> + dax_wake_entry(xas, entry, WAKE_NEXT);
> }
>
> /*
> @@ -524,7 +535,7 @@ static void *grab_mapping_entry(struct xa_state *xas,
>
> dax_disassociate_entry(entry, mapping, false);
> xas_store(xas, NULL); /* undo the PMD join */
> - dax_wake_entry(xas, entry, true);
> + dax_wake_entry(xas, entry, WAKE_ALL);
> mapping->nrexceptional--;
> entry = NULL;
> xas_set(xas, index);
> @@ -937,7 +948,7 @@ static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
> xas_lock_irq(xas);
> xas_store(xas, entry);
> xas_clear_mark(xas, PAGECACHE_TAG_DIRTY);
> - dax_wake_entry(xas, entry, false);
> + dax_wake_entry(xas, entry, WAKE_NEXT);
>
> trace_dax_writeback_one(mapping->host, index, count);
> return ret;
next prev parent reply other threads:[~2021-04-20 7:35 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-19 21:36 [PATCH v3 0/3] dax: Fix missed wakeup in put_unlocked_entry() Vivek Goyal
2021-04-19 21:36 ` [PATCH v3 1/3] dax: Add an enum for specifying dax wakup mode Vivek Goyal
2021-04-20 7:19 ` Greg Kurz [this message]
2021-04-21 9:24 ` Jan Kara
2021-04-21 15:56 ` Vivek Goyal
2021-04-21 16:16 ` Matthew Wilcox
2021-04-21 17:21 ` Vivek Goyal
2021-04-19 21:36 ` [PATCH v3 2/3] dax: Add a wakeup mode parameter to put_unlocked_entry() Vivek Goyal
2021-04-20 7:34 ` [Virtio-fs] " Greg Kurz
2021-04-20 14:00 ` Vivek Goyal
2021-04-21 19:09 ` Dan Williams
2021-04-21 19:13 ` Vivek Goyal
2021-04-22 6:24 ` Christoph Hellwig
2021-04-22 16:12 ` Darrick J. Wong
2021-04-22 20:01 ` Dan Williams
2021-04-22 20:07 ` Vivek Goyal
2021-05-17 17:10 ` Dan Williams
2021-04-21 17:39 ` Vivek Goyal
2021-04-21 9:25 ` Jan Kara
2021-04-19 21:36 ` [PATCH v3 3/3] dax: Wake up all waiters after invalidating dax entry Vivek Goyal
2021-04-21 9:26 ` Jan Kara
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