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From: Muchun Song In-Reply-To: <5e091211-9a32-8480-55fb-faff6a0fadef@linux.dev> Date: Wed, 6 Sep 2023 16:07:20 +0800 Cc: Muchun Song , Joao Martins , Oscar Salvador , David Hildenbrand , Miaohe Lin , David Rientjes , Anshuman Khandual , Naoya Horiguchi , Barry Song , Michal Hocko , Matthew Wilcox , Xiongchun Duan , Andrew Morton Content-Transfer-Encoding: quoted-printable Message-Id: <38E2F051-E00B-4104-A616-0EEB2729386F@linux.dev> References: <20230905214412.89152-1-mike.kravetz@oracle.com> <20230905214412.89152-8-mike.kravetz@oracle.com> <5e091211-9a32-8480-55fb-faff6a0fadef@linux.dev> To: Mike Kravetz , Linux-MM , LKML X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 0E6911A001C X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 98f7pd5pd74ib9qboswkm1rr4wku4im8 X-HE-Tag: 1693987684-888664 X-HE-Meta: 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 3Dky59gl 7h+5m5WanMoUs/0FPdXQrcuqsZF7Xmz1xobA75yvkO9PAlbgSiJejyvaw3JMb3+kTrAUymn1b+b9nZyaX4tQKMLSrbHDvp3qHSfiNqXHsxW/wqiNQ/PHv7RSp5z36XaINPN2klxGpcjHZu8g7wWOeA8hSzwUt/mOF5ifE+t52KC8c01o= 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 Sep 6, 2023, at 15:33, Muchun Song wrote: >=20 >=20 >=20 > On 2023/9/6 05:44, Mike Kravetz wrote: >> When removing hugetlb pages from the pool, we first create a list >> of removed pages and then free those pages back to low level = allocators. >> Part of the 'freeing process' is to restore vmemmap for all base = pages >> if necessary. Pass this list of pages to a new routine >> hugetlb_vmemmap_restore_folios() so that vmemmap restoration can be >> performed in bulk. >>=20 >> Signed-off-by: Mike Kravetz >> --- >> mm/hugetlb.c | 3 +++ >> mm/hugetlb_vmemmap.c | 13 +++++++++++++ >> mm/hugetlb_vmemmap.h | 5 +++++ >> 3 files changed, 21 insertions(+) >>=20 >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index 554be94b07bd..dd2dbc256172 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -1838,6 +1838,9 @@ static void update_and_free_pages_bulk(struct = hstate *h, struct list_head *list) >> { >> struct folio *folio, *t_folio; >> + /* First restore vmemmap for all pages on list. */ >> + hugetlb_vmemmap_restore_folios(h, list); >> + >> list_for_each_entry_safe(folio, t_folio, list, lru) { >> update_and_free_hugetlb_folio(h, folio, false); >> cond_resched(); >> diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c >> index ac5577d372fe..79de984919ef 100644 >> --- a/mm/hugetlb_vmemmap.c >> +++ b/mm/hugetlb_vmemmap.c >> @@ -481,6 +481,19 @@ int hugetlb_vmemmap_restore(const struct hstate = *h, struct page *head) >> return ret; >> } >> +/* >> + * This function will attempt to resore vmemmap for a list of = folios. There >> + * is no guarantee that restoration will be successful for all or = any folios. >> + * This is used in bulk operations, and no feedback is given to the = caller. >> + */ >> +void hugetlb_vmemmap_restore_folios(const struct hstate *h, struct = list_head *folio_list) >> +{ >> + struct folio *folio; >> + >> + list_for_each_entry(folio, folio_list, lru) >> + (void)hugetlb_vmemmap_restore(h, &folio->page); >=20 > I am curious about the purpose of "void" here, seems it it not = necessnary, > ritgh? We cound see so many palces where we do not add the void if the = caller > does not care about the return value of the callee. Another question: should we stop restoring vmemmap pages when hugetlb_vmemmap_restore() fails? In which case, I suspect there is no memory probably, there is no need to continue, right? >=20 > Thanks. >> +} >> + >> /* Return true iff a HugeTLB whose vmemmap should and can be = optimized. */ >> static bool vmemmap_should_optimize(const struct hstate *h, const = struct page *head) >> { >> diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h >> index 036494e040ca..b4ee945dc1d4 100644 >> --- a/mm/hugetlb_vmemmap.h >> +++ b/mm/hugetlb_vmemmap.h >> @@ -12,6 +12,7 @@ >> #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP >> int hugetlb_vmemmap_restore(const struct hstate *h, struct page = *head); >> +void hugetlb_vmemmap_restore_folios(const struct hstate *h, struct = list_head *folio_list); >> void hugetlb_vmemmap_optimize(const struct hstate *h, struct page = *head); >> void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct = list_head *folio_list); >> @@ -44,6 +45,10 @@ static inline int hugetlb_vmemmap_restore(const = struct hstate *h, struct page *h >> return 0; >> } >> +static inline void hugetlb_vmemmap_restore_folios(const struct = hstate *h, struct list_head *folio_list) >> +{ >> +} >> + >> static inline void hugetlb_vmemmap_optimize(const struct hstate *h, = struct page *head) >> { >> } >=20