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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qrKFA-006A5i-Gv; Fri, 13 Oct 2023 15:38:28 +0000 Date: Fri, 13 Oct 2023 16:38:28 +0100 From: Matthew Wilcox To: "zhaoyang.huang" Cc: Andrew Morton , Johannes Weiner , Suren Baghdasaryan , Michal Hocko , Yu Zhao , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Zhaoyang Huang , steve.kang@unisoc.com Subject: Re: [RFC PATCH 1/1] mm: only use old generation and stable tier for madv_pageout Message-ID: References: <20231013113028.2720996-1-zhaoyang.huang@unisoc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231013113028.2720996-1-zhaoyang.huang@unisoc.com> X-Rspamd-Queue-Id: AFBF7120026 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: zbzms8hjdsco4y569xcpaq1ejxb5ttri X-HE-Tag: 1697211524-964411 X-HE-Meta: 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 WdKbz683 79JiTj3J4U6rJg041YP7HHyeQ7V64WbTbFBw8U+PplOd5o82n+4j7JS8D6go2mFtSiS21HvhdAwg6YOQGI2UetXP8Jd0P5HTQuXTyvGezHum7S1PP6QKF5jS6Vbf6l3AThMJEJjVuOgJ5ISbrggPXhW/mE69NHAEXBGrQtNnOcyPq8kiMVyQsFHcKyKfdFv1XJqcabfSkE5kgBakFkgYkfvqnHJ1dO5MGZjnWJyq6+2amVuzGvVs4rqnTGA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Oct 13, 2023 at 07:30:28PM +0800, zhaoyang.huang wrote: > From: Zhaoyang Huang > > Dropping pages of young generation or unstable tier via madvise could > make the system experience heavy page thrashing and IO pressure. ... then userspace should not do that? > @@ -5091,6 +5091,7 @@ static int get_tier_idx(struct lruvec *lruvec, int type) > > return tier - 1; > } > +EXPORT_SYMBOL_GPL(get_tier_idx); Why would this need to be exported to modules in order to be used by madvise? Is this patch just a trojan horse so you can use get_tier_idx in your own module? NAK.