[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <20151002130345.GS3068@techsingularity.net>
Date: Fri, 2 Oct 2015 14:03:45 +0100
From: Mel Gorman <mgorman@...hsingularity.net>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Vlastimil Babka <vbabka@...e.cz>,
Johannes Weiner <hannes@...xchg.org>,
Rik van Riel <riel@...hat.com>,
David Rientjes <rientjes@...gle.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Michal Hocko <mhocko@...nel.org>,
Linux-MM <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] mm: page_alloc: Hide some GFP internals and document the
bits and flag combinations -fix
This patch address minor comment nitpicks from Vlastimil. It is a fix for the
mmotm patch
mm-page_alloc-hide-some-GFP-internals-and-document-the-bit-and-flag-combinations.patch
Signed-off-by: Mel Gorman <mgorman@...hsingularity.net>
---
include/linux/gfp.h | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 67654f08a28b..4ab8cfa0aa9f 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -110,17 +110,18 @@ struct vm_area_struct;
*
* __GFP_IO can start physical IO.
*
- * __GFP_FS can call down to the low-level FS. Avoids the allocator
- * recursing into the filesystem which might already be holding locks.
+ * __GFP_FS can call down to the low-level FS. Clearing the flag avoids the
+ * allocator recursing into the filesystem which might already be holding
+ * locks.
*
* __GFP_DIRECT_RECLAIM indicates that the caller may enter direct reclaim.
* This flag can be cleared to avoid unnecessary delays when a fallback
* option is available.
*
- * __GFP_KSWAPD_RECLAIM indicates that the caller wants kswapd when the low
- * watermark is reached and have it reclaim pages until the high watermark
- * is reached. A caller may wish to clear this flag when fallback options
- * are available and the reclaim is likely to disrupt the system. The
+ * __GFP_KSWAPD_RECLAIM indicates that the caller wants to wake kswapd when
+ * the low watermark is reached and have it reclaim pages until the high
+ * watermark is reached. A caller may wish to clear this flag when fallback
+ * options are available and the reclaim is likely to disrupt the system. The
* canonical example is THP allocation where a fallback is cheap but
* reclaim/compaction may cause indirect stalls.
*
@@ -208,11 +209,6 @@ struct vm_area_struct;
* for buffers that are mapped to userspace (e.g. graphics) that hardware
* still must DMA to. cpuset limits are enforced for these allocations.
*
- * GFP_HIGHUSER is for userspace allocations that may be mapped to userspace,
- * do not need to be directly accessible by the kernel but that cannot
- * move once in use. An example may be a hardware allocation that maps
- * data directly into userspace but has no addressing limitations.
- *
* GFP_DMA exists for historical reasons and should be avoided where possible.
* The flags indicates that the caller requires that the lowest zone be
* used (ZONE_DMA or 16M on x86-64). Ideally, this would be removed but
@@ -223,6 +219,11 @@ struct vm_area_struct;
* GFP_DMA32 is similar to GFP_DMA except that the caller requires a 32-bit
* address.
*
+ * GFP_HIGHUSER is for userspace allocations that may be mapped to userspace,
+ * do not need to be directly accessible by the kernel but that cannot
+ * move once in use. An example may be a hardware allocation that maps
+ * data directly into userspace but has no addressing limitations.
+ *
* GFP_HIGHUSER_MOVABLE is for userspace allocations that the kernel does not
* need direct access to but can use kmap() when access is required. They
* are expected to be movable via page reclaim or page migration. Typically,
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists