linux-kernel - Re: [PATCH net-next v17 03/14] mm: page_frag: use initial zero offset for page_frag_alloc

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Message-ID: <CAKgT0UfqH0tyB0tWavkx2cE+1YhW1ZGhqg271=s8_hvSCzQkpw@mail.gmail.com>
Date: Wed, 4 Sep 2024 08:47:03 -0700
From: Alexander Duyck <alexander.duyck@...il.com>
To: Yunsheng Lin <linyunsheng@...wei.com>
Cc: davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com, 
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org
Subject: Re: [PATCH net-next v17 03/14] mm: page_frag: use initial zero offset
 for page_frag_alloc_align()

On Mon, Sep 2, 2024 at 5:09 AM Yunsheng Lin <linyunsheng@...wei.com> wrote:
>
> We are about to use page_frag_alloc_*() API to not just
> allocate memory for skb->data, but also use them to do
> the memory allocation for skb frag too. Currently the
> implementation of page_frag in mm subsystem is running
> the offset as a countdown rather than count-up value,
> there may have several advantages to that as mentioned
> in [1], but it may have some disadvantages, for example,
> it may disable skb frag coalescing and more correct cache
> prefetching
>
> We have a trade-off to make in order to have a unified
> implementation and API for page_frag, so use a initial zero
> offset in this patch, and the following patch will try to
> make some optimization to avoid the disadvantages as much
> as possible.
>
> 1. https://lore.kernel.org/all/f4abe71b3439b39d17a6fb2d410180f367cadf5c.camel@gmail.com/
>
> CC: Alexander Duyck <alexander.duyck@...il.com>
> Signed-off-by: Yunsheng Lin <linyunsheng@...wei.com>
> ---
>  mm/page_frag_cache.c | 46 ++++++++++++++++++++++----------------------
>  1 file changed, 23 insertions(+), 23 deletions(-)
>

Reviewed-by: Alexander Duyck <alexanderduyck@...com>