From: Mel Gorman <mgorman@techsingularity.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@redhat.com>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Michal Hocko <mhocko@kernel.org>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH] mm: page_alloc: Hide some GFP internals and document the bits and flag combinations -fix
Date: Fri, 2 Oct 2015 14:03:45 +0100 [thread overview]
Message-ID: <20151002130345.GS3068@techsingularity.net> (raw)
In-Reply-To: <560CF134.2060107@suse.cz>
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@techsingularity.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,
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next prev parent reply other threads:[~2015-10-02 13:03 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-21 10:52 [PATCH 00/10] Remove zonelist cache and high-order watermark checking v4 Mel Gorman
2015-09-21 10:52 ` [PATCH 01/10] mm, page_alloc: Remove unnecessary parameter from zone_watermark_ok_safe Mel Gorman
2015-09-24 20:01 ` Johannes Weiner
2015-09-21 10:52 ` [PATCH 02/10] mm, page_alloc: Remove unnecessary recalculations for dirty zone balancing Mel Gorman
2015-09-24 20:05 ` Johannes Weiner
2015-09-21 10:52 ` [PATCH 03/10] mm, page_alloc: Remove unnecessary taking of a seqlock when cpusets are disabled Mel Gorman
2015-09-24 20:06 ` Johannes Weiner
2015-09-30 22:22 ` David Rientjes
2015-10-01 7:35 ` Vlastimil Babka
2015-09-21 10:52 ` [PATCH 04/10] mm, page_alloc: Use masks and shifts when converting GFP flags to migrate types Mel Gorman
2015-09-24 20:34 ` Johannes Weiner
2015-09-25 12:50 ` Mel Gorman
2015-09-25 13:56 ` Johannes Weiner
2015-09-21 10:52 ` [PATCH 05/10] mm, page_alloc: Distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd Mel Gorman
2015-09-24 13:51 ` Michal Hocko
2015-09-24 20:55 ` Johannes Weiner
2015-09-25 12:51 ` Mel Gorman
2015-09-25 19:01 ` Johannes Weiner
2015-09-29 13:35 ` Mel Gorman
2015-09-30 12:26 ` Vlastimil Babka
2015-09-30 13:17 ` Mel Gorman
2015-10-01 3:04 ` Drokin, Oleg
2015-10-02 12:30 ` Mel Gorman
2015-09-21 10:52 ` [PATCH 06/10] mm, page_alloc: Rename __GFP_WAIT to __GFP_RECLAIM Mel Gorman
2015-09-25 19:03 ` Johannes Weiner
2015-09-28 23:55 ` Andrew Morton
2015-09-29 13:37 ` Mel Gorman
2015-10-01 8:39 ` Vlastimil Babka
2015-10-02 13:03 ` Mel Gorman [this message]
2015-10-01 14:06 ` Michal Hocko
2015-09-30 22:25 ` David Rientjes
2015-09-21 10:52 ` [PATCH 07/10] mm, page_alloc: Delete the zonelist_cache Mel Gorman
2015-09-25 19:09 ` Johannes Weiner
2015-09-21 10:52 ` [PATCH 08/10] mm, page_alloc: Remove MIGRATE_RESERVE Mel Gorman
2015-09-21 10:52 ` [PATCH 09/10] mm, page_alloc: Reserve pageblocks for high-order atomic allocations on demand Mel Gorman
2015-09-24 13:50 ` Michal Hocko
2015-09-25 19:22 ` Johannes Weiner
2015-09-29 21:01 ` Andrew Morton
2015-09-30 8:27 ` Mel Gorman
2015-09-30 14:02 ` Vlastimil Babka
2015-09-21 12:03 ` [PATCH 10/10] mm, page_alloc: Only enforce watermarks for order-0 allocations Mel Gorman
2015-09-25 19:32 ` Johannes Weiner
2015-09-29 21:05 ` Andrew Morton
2015-09-30 8:46 ` Mel Gorman
2015-09-30 14:17 ` Vlastimil Babka
2015-09-30 15:12 ` Mel Gorman
2015-09-30 20:37 ` Andrew Morton
2015-09-30 14:11 ` Vlastimil Babka
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