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From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Matthew Wilcox <willy@infradead.org>
CC:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        Neil Brown <neilb@suse.de>
Subject: Re: [PATCH v3 2/3] SUNRPC: Add svc_rqst_replace_page() API
Thread-Topic: [PATCH v3 2/3] SUNRPC: Add svc_rqst_replace_page() API
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Date:   Fri, 9 Jul 2021 03:04:44 +0000
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> On Jul 8, 2021, at 7:30 PM, Matthew Wilcox <willy@infradead.org> wrote:
>=20
> On Thu, Jul 08, 2021 at 11:26:29AM -0400, Chuck Lever wrote:
>> @@ -256,6 +256,9 @@ struct svc_rqst {
>> 	struct page *		*rq_next_page; /* next reply page to use */
>> 	struct page *		*rq_page_end;  /* one past the last page */
>>=20
>> +	struct page		*rq_relpages[16];
>> +	int			rq_numrelpages;
>=20
> This is only one struct page away from being a pagevec ... ?
>=20
>> @@ -838,6 +839,33 @@ svc_set_num_threads_sync(struct svc_serv *serv, str=
uct svc_pool *pool, int nrser
>> }
>> EXPORT_SYMBOL_GPL(svc_set_num_threads_sync);
>>=20
>> +static void svc_rqst_release_replaced_pages(struct svc_rqst *rqstp)
>> +{
>> +	release_pages(rqstp->rq_relpages, rqstp->rq_numrelpages);
>> +	rqstp->rq_numrelpages =3D 0;
>=20
> This would be pagevec_release()

 986 void __pagevec_release(struct pagevec *pvec)
 987 {
 988         if (!pvec->percpu_pvec_drained) {
 989                 lru_add_drain();
 990                 pvec->percpu_pvec_drained =3D true;
 991         }
 992         release_pages(pvec->pages, pagevec_count(pvec));
 993         pagevec_reinit(pvec);
 994 }

Pretty much the same under the bonnet. Fair enough!


--
Chuck Lever