linux-kernel - [PATCH v10 05/18] mm: mark vmas detached upon exit

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Message-ID: <20250213224655.1680278-6-surenb@google.com>
Date: Thu, 13 Feb 2025 14:46:42 -0800
From: Suren Baghdasaryan <surenb@...gle.com>
To: akpm@...ux-foundation.org
Cc: peterz@...radead.org, willy@...radead.org, liam.howlett@...cle.com, 
	lorenzo.stoakes@...cle.com, david.laight.linux@...il.com, mhocko@...e.com, 
	vbabka@...e.cz, hannes@...xchg.org, mjguzik@...il.com, oliver.sang@...el.com, 
	mgorman@...hsingularity.net, david@...hat.com, peterx@...hat.com, 
	oleg@...hat.com, dave@...olabs.net, paulmck@...nel.org, brauner@...nel.org, 
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	lokeshgidra@...gle.com, minchan@...gle.com, jannh@...gle.com, 
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	linux-doc@...r.kernel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org, 
	kernel-team@...roid.com, surenb@...gle.com
Subject: [PATCH v10 05/18] mm: mark vmas detached upon exit

When exit_mmap() removes vmas belonging to an exiting task, it does not
mark them as detached since they can't be reached by other tasks and they
will be freed shortly. Once we introduce vma reuse, all vmas will have to
be in detached state before they are freed to ensure vma when reused is
in a consistent state. Add missing vma_mark_detached() before freeing the
vma.

Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
Reviewed-by: Vlastimil Babka <vbabka@...e.cz>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
---
Changes since v9 [1]:
- Add Reviewed-by, per Lorenzo Stoakes

[1] https://lore.kernel.org/all/20250111042604.3230628-6-surenb@google.com/

 mm/vma.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/vma.c b/mm/vma.c
index f72b73f57451..a16a83d0253f 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -427,10 +427,12 @@ void remove_vma(struct vm_area_struct *vma, bool unreachable)
 	if (vma->vm_file)
 		fput(vma->vm_file);
 	mpol_put(vma_policy(vma));
-	if (unreachable)
+	if (unreachable) {
+		vma_mark_detached(vma);
 		__vm_area_free(vma);
-	else
+	} else {
 		vm_area_free(vma);
+	}
 }
 
 /*
-- 
2.48.1.601.g30ceb7b040-goog