[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <48417f46-d01c-48d1-b53e-d9458a1527fe@arm.com>
Date: Mon, 27 Nov 2023 10:34:59 +0000
From: Ryan Roberts <ryan.roberts@....com>
To: David Hildenbrand <david@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Matthew Wilcox <willy@...radead.org>,
Yin Fengwei <fengwei.yin@...el.com>,
Yu Zhao <yuzhao@...gle.com>,
Catalin Marinas <catalin.marinas@....com>,
Anshuman Khandual <anshuman.khandual@....com>,
Yang Shi <shy828301@...il.com>,
"Huang, Ying" <ying.huang@...el.com>, Zi Yan <ziy@...dia.com>,
Luis Chamberlain <mcgrof@...nel.org>,
Itaru Kitayama <itaru.kitayama@...il.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
John Hubbard <jhubbard@...dia.com>,
David Rientjes <rientjes@...gle.com>,
Vlastimil Babka <vbabka@...e.cz>,
Hugh Dickins <hughd@...gle.com>,
Kefeng Wang <wangkefeng.wang@...wei.com>
Cc: linux-mm@...ck.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH v7 02/10] mm: Non-pmd-mappable, large folios for
folio_add_new_anon_rmap()
On 24/11/2023 17:40, David Hildenbrand wrote:
> On 22.11.23 17:29, Ryan Roberts wrote:
>> In preparation for supporting anonymous small-sized THP, improve
>> folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be
>> passed to it. In this case, all contained pages are accounted using the
>> order-0 folio (or base page) scheme.
>>
>> Reviewed-by: Yu Zhao <yuzhao@...gle.com>
>> Reviewed-by: Yin Fengwei <fengwei.yin@...el.com>
>> Signed-off-by: Ryan Roberts <ryan.roberts@....com>
>> ---
>> mm/rmap.c | 28 ++++++++++++++++++++--------
>> 1 file changed, 20 insertions(+), 8 deletions(-)
>>
>> diff --git a/mm/rmap.c b/mm/rmap.c
>> index 49e4d86a4f70..b086dc957b0c 100644
>> --- a/mm/rmap.c
>> +++ b/mm/rmap.c
>> @@ -1305,32 +1305,44 @@ void page_add_anon_rmap(struct page *page, struct
>> vm_area_struct *vma,
>> * This means the inc-and-test can be bypassed.
>> * The folio does not have to be locked.
>> *
>> - * If the folio is large, it is accounted as a THP. As the folio
>> + * If the folio is pmd-mappable, it is accounted as a THP. As the folio
>> * is new, it's assumed to be mapped exclusively by a single process.
>> */
>> void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
>> unsigned long address)
>> {
>> - int nr;
>> + int nr = folio_nr_pages(folio);
>>
>> - VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
>> + VM_BUG_ON_VMA(address < vma->vm_start ||
>> + address + (nr << PAGE_SHIFT) > vma->vm_end, vma);
>> __folio_set_swapbacked(folio);
>> + __folio_set_anon(folio, vma, address, true);
>
> Likely the changed order doesn't matter.
Yes; the reason I moved __folio_set_anon() up here is because
SetPageAnonExclusive() asserts that the page is anon, and SetPageAnonExclusive()
has to be called differently for the 3 cases. I couldn't see any reason why it
wouldn't be safe to call __folio_set_anon() before setting up the mapcounts.
>
> LGTM
>
> Reviewed-by: David Hildenbrand <david@...hat.com>
>
Thanks!
Powered by blists - more mailing lists