The patch titled
Subject: mm: vrealloc: consider spare memory for __GFP_ZERO
has been added to the -mm mm-unstable branch. Its filename is
mm-vmalloc-implement-vrealloc-fix-3.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-implement-vrealloc-fix-3.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Danilo Krummrich <dakr@xxxxxxxxxx>
Subject: mm: vrealloc: consider spare memory for __GFP_ZERO
Date: Tue, 30 Jul 2024 20:49:42 +0200
Zero spare memory when shrinking a buffer with __GFP_ZERO.
Link: https://lkml.kernel.org/r/20240730185049.6244-3-dakr@xxxxxxxxxx
Fixes: 1f39ee9615a8 ("mm: vmalloc: implement vrealloc()")
Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/mm/vmalloc.c~mm-vmalloc-implement-vrealloc-fix-3
+++ a/mm/vmalloc.c
@@ -4077,12 +4077,15 @@ void *vrealloc_noprof(const void *p, siz
old_size = get_vm_area_size(vm);
}
+ /*
+ * TODO: Shrink the vm_area, i.e. unmap and free unused pages. What
+ * would be a good heuristic for when to shrink the vm_area?
+ */
if (size <= old_size) {
- /*
- * TODO: Shrink the vm_area, i.e. unmap and free unused pages.
- * What would be a good heuristic for when to shrink the
- * vm_area?
- */
+ /* Zero out spare memory. */
+ if (want_init_on_alloc(flags))
+ memset((void *)p + size, 0, old_size - size);
+
return (void *)p;
}
_
Patches currently in -mm which might be from dakr@xxxxxxxxxx are
mm-vmalloc-implement-vrealloc.patch
mm-vmalloc-implement-vrealloc-fix.patch
mm-vmalloc-implement-vrealloc-fix-2.patch
mm-vmalloc-implement-vrealloc-fix-3.patch
mm-kvmalloc-align-kvrealloc-with-krealloc.patch
mm-kvmalloc-align-kvrealloc-with-krealloc-fix.patch
mm-kvmalloc-align-kvrealloc-with-krealloc-fix-2.patch
