[PATCH v2 35/40] mm: eliminate VMA_SPECIAL_FLAGS check in lru_gen_look_around()
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Date: 2026-09-14 15:15:34
Also in:
bpf, dri-devel, fuse-devel, kvm, kvm-riscv, kvmarm, linux-arch, linux-doc, linux-fbdev, linux-fsdevel, linux-mm, linux-perf-users, linux-rdma, linux-riscv, linux-s390, linux-scsi, linux-sound, linux-trace-kernel, linux-usb, lkml, selinux, sparclinux
Subsystem:
memory management, memory management - mglru (multi-gen lru), memory management - reclaim, the rest · Maintainers:
Andrew Morton, Johannes Weiner, Linus Torvalds
A kernel-owned or fixed mapping is one which sets VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT or VMA_DONTEXPAND_BIT, which is precisely what VMA_SPECIAL_FLAGS tests for other than VMA_IO_BIT, which is safe to drop as only kernel-owned mappings may set it. Using these predicates rather than VMA_SPECIAL_FLAGS makes the check self-documenting and helps eliminate the confusion around 'special' flags. No functional change intended. Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org> --- mm/vmscan.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 09ff20c3df5b..001f8b760266 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c@@ -4418,8 +4418,8 @@ bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw, unsigned int nr) if (spin_is_contended(pvmw->ptl)) return true; - /* exclude special VMAs containing anon pages from COW */ - if (vma->vm_flags & VM_SPECIAL) + /* exclude kernel-owned and fixed VMAs containing anon pages from COW */ + if (vma_is_kernel_owned(vma) || vma_is_fixed_mapping(vma)) return true; /* avoid taking the LRU lock under the PTL when possible */
--
2.55.0