diff options
| author |   Jann Horn <jannh@google.com> | 2025-05-28 23:06:17 +0200 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2025-05-31 22:46:14 -0700 |
| commit | 52084f258e46f09a71063447df31cbd48c0cacd0 (patch) | |
| tree | 0adf62f8e9f431285ca1af7ce3dabd277201fd60 /mm | |
| parent | selftests/mm: two fixes for the pfnmap test (diff) | |
| download | linux-rng-52084f258e46f09a71063447df31cbd48c0cacd0.tar.xz linux-rng-52084f258e46f09a71063447df31cbd48c0cacd0.zip | |
mm/gup: update comment explaining why gup_fast() disables IRQs
The current comment in gup_fast() talks about "IPIs that come from THPs
splitting", which is outdated and refers to the old THP splitting
implementation that was removed in commit ad0bed24e98b ("thp: drop all
split_huge_page()-related code"), which landed in v4.5. Before then, THP
splitting involved a pmdp_splitting_flush(), which sent an IPI to
serialize against gup_fast().
Nowadays, we use tlb_remove_table_sync_one() to send IPIs that serialize
against gup_fast(); this is used, for example, in THP *collapsing* to stop
gup_fast() walks of a page table before depositing it.
Link: https://lkml.kernel.org/r/20250528-gup-irq-comment-fix-v1-1-b9d83c345333@google.com
Signed-off-by: Jann Horn <jannh@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shuemov <kirill.shutemov@linux.intel.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/gup.c | 2 |
1 files changed, 1 insertions, 1 deletions
@@ -3299,7 +3299,7 @@ static unsigned long gup_fast(unsigned long start, unsigned long end, * include/asm-generic/tlb.h for more details. * * We do not adopt an rcu_read_lock() here as we also want to block IPIs - * that come from THPs splitting. + * that come from callers of tlb_remove_table_sync_one(). */ local_irq_save(flags); gup_fast_pgd_range(start, end, gup_flags, pages, &nr_pinned); |