Thread (140 messages) 140 messages, 10 authors, 13d ago

Re: [PATCH 05/30] mm/rmap: update mm/interval_tree.c comments

From: Lorenzo Stoakes <ljs@kernel.org>
Date: 2026-06-29 16:41:43
Also in: damon, dri-devel, kvm, linux-arm-msm, linux-fsdevel, linux-iommu, linux-mm, linux-perf-users, linux-tegra, lkml, nvdimm

On Mon, Jun 29, 2026 at 12:01:02PM -0400, Gregory Price wrote:
On Mon, Jun 29, 2026 at 01:23:16PM +0100, Lorenzo Stoakes wrote:
quoted
Update the file comment to clarify that both file-backed and anonymous
interval trees are provided, referencing the relevant data types for
clarity.
Isn't this self-evident by nature of the function definitions?
(one takes a vm_area_struct, the other takes an anon_vma_chain)
Well you see you're already hitting up on issues there, they both take an
rb_root_cached and the vma_*() ones do not instantly scream 'file-backed' do
they? As VMAs are obviously used for buth anon and file-backed...

But later patches fix this stuff :)

And I feel it's hard visually to see where one set of definitions end and
another begins, which was really the motive for this, as trivial as it is!
quoted
-	VM_BUG_ON_VMA(vma_start_pgoff(node) != vma_start_pgoff(prev), node);
+	VM_WARN_ON_ONCE_VMA(vma_start_pgoff(node) != vma_start_pgoff(prev), node);
For my own edification - I know not to add new BUG(), should I be
converting BUG->WARN/something when i find them in areas i happen to be
working in?
Yeah pretty much in all cases.

It's very rare that you'd want the kernel to definitely oops, and I can't think
of any circumstance where you'd only what that if CONFIG_DEBUG_VM was set :))
~Gregory
Cheers, Lorenzo
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