Messages in this thread | | | From | Ilias Apalodimas <> | Date | Fri, 15 Dec 2023 13:58:19 +0200 | Subject | Re: [PATCH net-next] page_pool: Rename frag_users to frag_cnt |
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Hi Yunsheng,
On Fri, 15 Dec 2023 at 13:10, Yunsheng Lin <linyunsheng@huawei.com> wrote: > > On 2023/12/15 15:31, Ilias Apalodimas wrote: > > Since [0] got merged, it's clear that 'pp_ref_count' is used to track > > the number of users for each page. On struct_page though we have > > a member called 'frag_users'. Despite of what the name suggests this is > > not the number of users. It instead represents the number of fragments of > > the current page. When we have a single page this is set to one. When we > > split the page this is set to the actual number of frags and later used > > in page_pool_drain_frag() to infer the real number of users. > > > > So let's rename it to something that matches the description above > > > > [0] > > Link: https://lore.kernel.org/netdev/20231212044614.42733-2-liangchen.linux@gmail.com/ > > Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> > > --- > > include/net/page_pool.h | 2 +- > > net/core/page_pool.c | 8 ++++---- > > 2 files changed, 5 insertions(+), 5 deletions(-) > > > > diff --git a/include/net/page_pool.h b/include/net/page_pool.h > > index 813c93499f20..957cd84bb3f4 100644 > > --- a/include/net/page_pool.h > > +++ b/include/net/page_pool.h > > @@ -158,7 +158,7 @@ struct page_pool { > > u32 pages_state_hold_cnt; > > unsigned int frag_offset; > > struct page *frag_page; > > - long frag_users; > > + long frag_cnt; > > I would rename it to something like refcnt_bais to mirror the pagecnt_bias > in struct page_frag_cache.
Sure
> > > > > #ifdef CONFIG_PAGE_POOL_STATS > > /* these stats are incremented while in softirq context */ > > diff --git a/net/core/page_pool.c b/net/core/page_pool.c > > index 9b203d8660e4..19a56a52ac8f 100644 > > --- a/net/core/page_pool.c > > +++ b/net/core/page_pool.c > > @@ -659,7 +659,7 @@ EXPORT_SYMBOL(page_pool_put_page_bulk); > > static struct page *page_pool_drain_frag(struct page_pool *pool, > > struct page *page) > > { > > - long drain_count = BIAS_MAX - pool->frag_users; > > + long drain_count = BIAS_MAX - pool->frag_cnt; > > drain_count = pool->refcnt_bais;
I think this is a typo right? This still remains long drain_count = BIAS_MAX - pool->refcnt_bias;
> > or > > remove it and use pool->refcnt_bais directly.
I don't see any reason for inverting the logic. The bias is the number of refs that should be accounted for during allocation. I'll just stick with the rename
> > > > > /* Some user is still using the page frag */ > > if (likely(page_pool_defrag_page(page, drain_count))) > > @@ -678,7 +678,7 @@ static struct page *page_pool_drain_frag(struct page_pool *pool, > > > > static void page_pool_free_frag(struct page_pool *pool) > > { > > - long drain_count = BIAS_MAX - pool->frag_users; > > + long drain_count = BIAS_MAX - pool->frag_cnt; > > Same here. > > > struct page *page = pool->frag_page; > > > > pool->frag_page = NULL; > > @@ -721,14 +721,14 @@ struct page *page_pool_alloc_frag(struct page_pool *pool, > > pool->frag_page = page; > > > > frag_reset: > > - pool->frag_users = 1; > > + pool->frag_cnt = 1; > > pool->refcnt_bais = BIAS_MAX - 1; > > > *offset = 0; > > pool->frag_offset = size; > > page_pool_fragment_page(page, BIAS_MAX); > > return page; > > } > > > > - pool->frag_users++; > > + pool->frag_cnt++; > > pool->refcnt_bais--; > > > pool->frag_offset = *offset + size; > > alloc_stat_inc(pool, fast); > > return page; > > -- > > 2.37.2 > > > > . > >
Thanks /Ilias
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