From: Matthew Wilcox <willy@infradead.org>
To: Zi Yan <ziy@nvidia.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Ryan Roberts <ryan.roberts@arm.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
David Hildenbrand <david@redhat.com>,
Yang Shi <yang@os.amperecomputing.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Yu Zhao <yuzhao@google.com>, John Hubbard <jhubbard@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
Kairui Song <kasong@tencent.com>
Subject: Re: [PATCH v10 2/8] mm/huge_memory: add two new (not yet used) functions for folio_split()
Date: Mon, 10 Mar 2025 17:00:31 +0000 [thread overview]
Message-ID: <Z88ar5YS99HsIRYo@casper.infradead.org> (raw)
In-Reply-To: <D94BB56F-4BA0-4376-B5C4-7E38D2D92624@nvidia.com>
On Mon, Mar 10, 2025 at 12:42:06PM -0400, Zi Yan wrote:
> > Because of the “Careful” comment. But new_folio->* should be fine,
> > since it is the same as new_head. So I probably can replace all
> > new_head with new_folio except those VM_BUG_ON_PAGE checks?
Why not also the VM_BUG_ON_PAGE check? I mean:
> @@ -3364,8 +3364,8 @@ static void __split_folio_to_order(struct folio *folio, int old_order,
> /* ->mapping in first and second tail page is replaced by other uses */
> VM_BUG_ON_PAGE(new_nr_pages > 2 && new_head->mapping != TAIL_MAPPING,
> new_head);
VM_BUG_ON_PAGE(new_nr_pages > 2 && new_folio->mapping != TAIL_MAPPING, new_head);
(or we could just ditch the assert entirely; it's not all that useful)
> - new_head->mapping = head->mapping;
> - new_head->index = head->index + index;
> + new_folio->mapping = head->mapping;
> + new_folio->index = head->index + index;
new_folio->mapping = folio->mapping
new_folio->index = folio->index +index;
(um, and that index + index looks weird; better name might be just 'i')
next prev parent reply other threads:[~2025-03-10 17:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-07 17:39 [PATCH v10 0/8] Buddy allocator like (or non-uniform) folio split Zi Yan
2025-03-07 17:39 ` [PATCH v10 1/8] xarray: add xas_try_split() to split a multi-index entry Zi Yan
2025-03-07 17:39 ` [PATCH v10 2/8] mm/huge_memory: add two new (not yet used) functions for folio_split() Zi Yan
2025-03-10 16:14 ` Zi Yan
2025-03-10 17:32 ` Zi Yan
2025-03-13 14:08 ` Zi Yan
2025-03-10 16:30 ` Matthew Wilcox
2025-03-10 16:39 ` Zi Yan
2025-03-10 16:42 ` Zi Yan
2025-03-10 17:00 ` Matthew Wilcox [this message]
2025-03-10 17:05 ` Zi Yan
2025-03-07 17:39 ` [PATCH v10 3/8] mm/huge_memory: move folio split common code to __folio_split() Zi Yan
2025-03-07 17:39 ` [PATCH v10 4/8] mm/huge_memory: add buddy allocator like (non-uniform) folio_split() Zi Yan
2025-03-07 17:39 ` [PATCH v10 5/8] mm/huge_memory: remove the old, unused __split_huge_page() Zi Yan
2025-03-07 17:39 ` [PATCH v10 6/8] mm/huge_memory: add folio_split() to debugfs testing interface Zi Yan
2025-03-07 17:40 ` [PATCH v10 7/8] mm/truncate: use folio_split() in truncate operation Zi Yan
2025-03-07 17:40 ` [PATCH v10 8/8] selftests/mm: add tests for folio_split(), buddy allocator like split Zi Yan
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