Re: [PATCH] mm: remove zap_page_range and create zap_vma_pages
From: Michal Hocko <mhocko@suse.com>
Date: 2023-01-04 07:46:33
Also in:
linux-mm, linux-riscv, linux-s390, linuxppc-dev, lkml
On Tue 03-01-23 16:27:32, Mike Kravetz wrote:
zap_page_range was originally designed to unmap pages within an address range that could span multiple vmas. While working on [1], it was discovered that all callers of zap_page_range pass a range entirely within a single vma. In addition, the mmu notification call within zap_page range does not correctly handle ranges that span multiple vmas. When crossing a vma boundary, a new mmu_notifier_range_init/end call pair with the new vma should be made. Instead of fixing zap_page_range, do the following: - Create a new routine zap_vma_pages() that will remove all pages within the passed vma. Most users of zap_page_range pass the entire vma and can use this new routine. - For callers of zap_page_range not passing the entire vma, instead call zap_page_range_single(). - Remove zap_page_range. [1] https://lore.kernel.org/linux-mm/20221114235507.294320-2-mike.kravetz@oracle.com/ (local) Suggested-by: Peter Xu <peterx@redhat.com> Signed-off-by: Mike Kravetz <redacted>
This looks even better than the previous version. Acked-by: Michal Hocko <mhocko@suse.com> minor nit [...]
quoted hunk ↗ jump to hunk
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index ad608ef2a243..ffa36cfe5884 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c@@ -2713,7 +2713,7 @@ void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb) * * The caller must hold lock_page_memcg(). Most callers have the folio * locked. A few have the folio blocked from truncation through other - * means (eg zap_page_range() has it mapped and is holding the page table + * means (eg zap_vma_pages() has it mapped and is holding the page table * lock). This can also be called from mark_buffer_dirty(), which I * cannot prove is always protected against truncate.
strictly speaking this should be unmap_page_range -- Michal Hocko SUSE Labs