From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC4B511715 for ; Mon, 11 Dec 2023 10:12:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ntcoumax" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02E2DC433C7; Mon, 11 Dec 2023 10:12:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702289527; bh=7ZXmd5rh4Rqq/IAxc7eaZo+Bf3FwdWSw0W4uYwdYPqc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ntcoumaxavZrdA6pD8HO9I8uUIV8ziJTPWMNGRdwJjYSchwfy9H3CNL2ebURgN+3B R0hm53oQ01uvFLYMR8UUxe2p+tdRc8kFvfQn2MM8crnkyHeMKJuQo2gzWiw7BM3jck ke2parp67vwgAdLXklisge+oUonDNQJ05JtAxeK3rbrrxRl835/3eDCCgvtrQpN1dN Sezx3LN/WrHm1hyH8h1plqEnMHvQisygz1TIktV2Qg3mfo2QjRAW0E2rcIVy6x7E82 iOfm6FluXlUeI/74HWL+xiFzLO1XRUKn/fYxJUJ5oOerHDynszMbzXxOwebxcHLGl1 XSMI0dwCT41+Q== Message-ID: <6f7f7724-12a0-45d5-80dc-a811b58783c8@kernel.org> Date: Mon, 11 Dec 2023 11:12:01 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v8 2/4] page_pool: halve BIAS_MAX for multiple user references of a fragment To: Alexander Duyck Cc: netdev@vger.kernel.org, linux-mm@kvack.org, kuba@kernel.org, ilias.apalodimas@linaro.org, jasowang@redhat.com, linyunsheng@huawei.com, Liang Chen , edumazet@google.com, davem@davemloft.net, almasrymina@google.com, pabeni@redhat.com References: <20231211035243.15774-1-liangchen.linux@gmail.com> <20231211035243.15774-3-liangchen.linux@gmail.com> Content-Language: en-US From: Jesper Dangaard Brouer In-Reply-To: <20231211035243.15774-3-liangchen.linux@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Alex, For page_pool BIAS stuff I would really appreciate your review please. -Jesper On 11/12/2023 04.52, Liang Chen wrote: > Referring to patch [1], in order to support multiple users referencing the > same fragment and prevent overflow from pp_ref_count growing, the initial > value of pp_ref_count is halved, leaving room for pp_ref_count to increment > before the page is drained. > > [1] > https://lore.kernel.org/all/20211009093724.10539-3-linyunsheng@huawei.com/ > > Signed-off-by: Liang Chen > Reviewed-by: Yunsheng Lin > --- > net/core/page_pool.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/core/page_pool.c b/net/core/page_pool.c > index 106220b1f89c..436f7ffea7b4 100644 > --- a/net/core/page_pool.c > +++ b/net/core/page_pool.c > @@ -26,7 +26,7 @@ > #define DEFER_TIME (msecs_to_jiffies(1000)) > #define DEFER_WARN_INTERVAL (60 * HZ) > > -#define BIAS_MAX LONG_MAX > +#define BIAS_MAX (LONG_MAX >> 1) > > #ifdef CONFIG_PAGE_POOL_STATS > /* alloc_stat_inc is intended to be used in softirq context */