Thread (47 messages) 47 messages, 4 authors, 2021-12-13

Re: [PATCH v2 07/34] mm: clarify __GFP_ZEROTAGS comment

From: Andrey Konovalov <andreyknvl@gmail.com>
Date: 2021-12-07 17:33:27
Also in: linux-arm-kernel, lkml

On Mon, Dec 6, 2021 at 10:44 PM [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: Andrey Konovalov <redacted>

__GFP_ZEROTAGS is intended as an optimization: if memory is zeroed during
allocation, it's possible to set memory tags at the same time with little
performance impact.

Clarify this intention of __GFP_ZEROTAGS in the comment.

Signed-off-by: Andrey Konovalov <redacted>
---
 include/linux/gfp.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index b976c4177299..dddd7597689f 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -232,8 +232,8 @@ struct vm_area_struct;
  *
  * %__GFP_ZERO returns a zeroed page on success.
  *
- * %__GFP_ZEROTAGS returns a page with zeroed memory tags on success, if
- * __GFP_ZERO is set.
+ * %__GFP_ZEROTAGS zeroes memory tags at allocation time if the memory itself
+ * is being zeroed (either via __GFP_ZERO or via init_on_alloc).
  *
  * %__GFP_SKIP_KASAN_POISON returns a page which does not need to be poisoned
  * on deallocation. Typically used for userspace pages. Currently only has an
--
2.25.1
Hi Peter,

Could you check whether I correctly understood the intention of
__GFP_ZEROTAGS and give your ack on this patch and the next one?

Thanks!
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