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Wed, 29 May 2024 10:16:24 +0800 Message-ID: Date: Wed, 29 May 2024 10:16:23 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/5] mm: add folio_mc_copy() To: Lance Yang CC: , , Tony Luck , Miaohe Lin , , Matthew Wilcox , David Hildenbrand , Muchun Song , Benjamin LaHaise , , Zi Yan , Jiaqi Yan , Hugh Dickins , Vishal Moola , Alistair Popple , Jane Chu , Oscar Salvador References: <20240528134513.2283548-1-wangkefeng.wang@huawei.com> <20240528134513.2283548-2-wangkefeng.wang@huawei.com> Content-Language: en-US From: Kefeng Wang In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm100001.china.huawei.com (7.185.36.93) X-Rspamd-Queue-Id: 2BE65C002A X-Stat-Signature: s3wrdg5jrjhb157e3xw6dn9bhjy5c8xt X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1716948988-875318 X-HE-Meta: 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 Y0p9Qq4R 9bMuykhs9pbkRV9aV3YhdiTW7oIYACk8XEAwUKEXkgJV5hZzYcGsUyM+1sjiIic+s8sDTNlOxz00dwDZ3UTtbUky/DpP0rPCohdTJzZiFeuTcMsvjEF63qNehw05fjpaeDku3+QWGgqjujiqBTs6tBRaszwKHWh6GlsjiJXYEqRa5w86XBdptRb3KCSc7ee2Tv8HbZit0vDXHBIs9kP2Oz5icawtQTXic5vrkEwd9fDc4aSuOXqv1DctWW5i+1sfoWPWttJSGFbS5knTE5SvQtNtgV8uTQ6/wdUQq8xUISrIx5jgH+561SbgCeeaVdfWfdGCv3pEcohI5EAV9ktwHIfq2Fw== 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: List-Subscribe: List-Unsubscribe: On 2024/5/28 22:17, Lance Yang wrote: > Hi Kefeng, > > On Tue, May 28, 2024 at 9:45 PM Kefeng Wang wrote: >> >> Add a #MC variant of folio_copy() which uses copy_mc_highpage() to >> support #MC handled during folio copy, it will be used in folio >> migration soon. >> >> Signed-off-by: Kefeng Wang >> --- >> include/linux/mm.h | 1 + >> mm/util.c | 20 ++++++++++++++++++++ >> 2 files changed, 21 insertions(+) >> >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index 12bf20ebae5a..0c78d67f787d 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -1321,6 +1321,7 @@ void put_pages_list(struct list_head *pages); >> >> void split_page(struct page *page, unsigned int order); >> void folio_copy(struct folio *dst, struct folio *src); >> +int folio_mc_copy(struct folio *dst, struct folio *src); >> >> unsigned long nr_free_buffer_pages(void); >> >> diff --git a/mm/util.c b/mm/util.c >> index c9e519e6811f..9462dbf7ce02 100644 >> --- a/mm/util.c >> +++ b/mm/util.c >> @@ -828,6 +828,26 @@ void folio_copy(struct folio *dst, struct folio *src) >> } >> EXPORT_SYMBOL(folio_copy); >> >> +int folio_mc_copy(struct folio *dst, struct folio *src) >> +{ >> + long nr = folio_nr_pages(src); >> + long i = 0; >> + int ret = 0; >> + >> + for (;;) { >> + if (copy_mc_highpage(folio_page(dst, i), folio_page(src, i))) { >> + ret = -EFAULT; >> + break; >> + } >> + if (++i == nr) >> + break; >> + cond_resched(); >> + } >> + >> + return ret; >> +} >> +EXPORT_SYMBOL(folio_mc_copy); > > The code below might be clearer: > > +int folio_mc_copy(struct folio *dst, struct folio *src) > +{ > + long nr = folio_nr_pages(src); > + long i = 0; > + > + for (;;) { > + if (copy_mc_highpage(folio_page(dst, i), folio_page(src, i))) > + return -EFAULT; > + if (++i == nr) > + break; > + cond_resched(); > + } > + > + return 0; > +} > +EXPORT_SYMBOL(folio_mc_copy); > > IMO, we can return the error code directly without needing to use the 'ret'. Clearer, will update, thanks > > Thanks, > Lance > >> + >> int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; >> int sysctl_overcommit_ratio __read_mostly = 50; >> unsigned long sysctl_overcommit_kbytes __read_mostly; >> -- >> 2.27.0 >> >> >