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Date:   Mon, 15 Jun 2020 16:25:56 +0200
From:   Oleksandr Natalenko <oleksandr@redhat.com>
To:     Nitin Gupta <nigupta@nvidia.com>
Cc:     Mel Gorman <mgorman@techsingularity.net>,
        Michal Hocko <mhocko@suse.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Matthew Wilcox <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        David Rientjes <rientjes@google.com>,
        Nitin Gupta <ngupta@nitingupta.dev>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-mm <linux-mm@kvack.org>,
        Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCH v6] mm: Proactive compaction
Message-ID: <20200615142556.5mekzzwvratx2n2i@butterfly.localdomain>
References: <20200601194822.30252-1-nigupta@nvidia.com>
 <20200615082901.eccfhaklq6fz4bh6@butterfly.localdomain>
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On Mon, Jun 15, 2020 at 10:29:01AM +0200, Oleksandr Natalenko wrote:
> Just to let you know, this fails to compile for me with THP disabled on
> v5.8-rc1:
> 
>   CC      mm/compaction.o
> In file included from ./include/linux/dev_printk.h:14,
>                  from ./include/linux/device.h:15,
>                  from ./include/linux/node.h:18,
>                  from ./include/linux/cpu.h:17,
>                  from mm/compaction.c:11:
> In function ‘fragmentation_score_zone’,
>     inlined from ‘__compact_finished’ at mm/compaction.c:1982:11,
>     inlined from ‘compact_zone’ at mm/compaction.c:2062:8:
> ./include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_397’ declared with attribute error: BUILD_BUG failed
>   392 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |                                      ^
> ./include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’
>   373 |    prefix ## suffix();    \
>       |    ^~~~~~
> ./include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’
>   392 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |  ^~~~~~~~~~~~~~~~~~~
> ./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
>    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>       |                                     ^~~~~~~~~~~~~~~~~~
> ./include/linux/build_bug.h:59:21: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
>    59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
>       |                     ^~~~~~~~~~~~~~~~
> ./include/linux/huge_mm.h:319:28: note: in expansion of macro ‘BUILD_BUG’
>   319 | #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
>       |                            ^~~~~~~~~
> ./include/linux/huge_mm.h:115:26: note: in expansion of macro ‘HPAGE_PMD_SHIFT’
>   115 | #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
>       |                          ^~~~~~~~~~~~~~~
> mm/compaction.c:64:32: note: in expansion of macro ‘HPAGE_PMD_ORDER’
>    64 | #define COMPACTION_HPAGE_ORDER HPAGE_PMD_ORDER
>       |                                ^~~~~~~~~~~~~~~
> mm/compaction.c:1898:28: note: in expansion of macro ‘COMPACTION_HPAGE_ORDER’
>  1898 |    extfrag_for_order(zone, COMPACTION_HPAGE_ORDER);
>       |                            ^~~~~~~~~~~~~~~~~~~~~~
> In function ‘fragmentation_score_zone’,
>     inlined from ‘kcompactd’ at mm/compaction.c:1918:12:
> ./include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_397’ declared with attribute error: BUILD_BUG failed
>   392 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |                                      ^
> ./include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’
>   373 |    prefix ## suffix();    \
>       |    ^~~~~~
> ./include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’
>   392 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |  ^~~~~~~~~~~~~~~~~~~
> ./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
>    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>       |                                     ^~~~~~~~~~~~~~~~~~
> ./include/linux/build_bug.h:59:21: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
>    59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
>       |                     ^~~~~~~~~~~~~~~~
> ./include/linux/huge_mm.h:319:28: note: in expansion of macro ‘BUILD_BUG’
>   319 | #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
>       |                            ^~~~~~~~~
> ./include/linux/huge_mm.h:115:26: note: in expansion of macro ‘HPAGE_PMD_SHIFT’
>   115 | #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
>       |                          ^~~~~~~~~~~~~~~
> mm/compaction.c:64:32: note: in expansion of macro ‘HPAGE_PMD_ORDER’
>    64 | #define COMPACTION_HPAGE_ORDER HPAGE_PMD_ORDER
>       |                                ^~~~~~~~~~~~~~~
> mm/compaction.c:1898:28: note: in expansion of macro ‘COMPACTION_HPAGE_ORDER’
>  1898 |    extfrag_for_order(zone, COMPACTION_HPAGE_ORDER);
>       |                            ^~~~~~~~~~~~~~~~~~~~~~
> In function ‘fragmentation_score_zone’,
>     inlined from ‘kcompactd’ at mm/compaction.c:1918:12:
> ./include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_397’ declared with attribute error: BUILD_BUG failed
>   392 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |                                      ^
> ./include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’
>   373 |    prefix ## suffix();    \
>       |    ^~~~~~
> ./include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’
>   392 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |  ^~~~~~~~~~~~~~~~~~~
> ./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
>    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>       |                                     ^~~~~~~~~~~~~~~~~~
> ./include/linux/build_bug.h:59:21: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
>    59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
>       |                     ^~~~~~~~~~~~~~~~
> ./include/linux/huge_mm.h:319:28: note: in expansion of macro ‘BUILD_BUG’
>   319 | #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
>       |                            ^~~~~~~~~
> ./include/linux/huge_mm.h:115:26: note: in expansion of macro ‘HPAGE_PMD_SHIFT’
>   115 | #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
>       |                          ^~~~~~~~~~~~~~~
> mm/compaction.c:64:32: note: in expansion of macro ‘HPAGE_PMD_ORDER’
>    64 | #define COMPACTION_HPAGE_ORDER HPAGE_PMD_ORDER
>       |                                ^~~~~~~~~~~~~~~
> mm/compaction.c:1898:28: note: in expansion of macro ‘COMPACTION_HPAGE_ORDER’
>  1898 |    extfrag_for_order(zone, COMPACTION_HPAGE_ORDER);
>       |                            ^~~~~~~~~~~~~~~~~~~~~~
> In function ‘fragmentation_score_zone’,
>     inlined from ‘kcompactd’ at mm/compaction.c:1918:12:
> ./include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_397’ declared with attribute error: BUILD_BUG failed
>   392 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |                                      ^
> ./include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’
>   373 |    prefix ## suffix();    \
>       |    ^~~~~~
> ./include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’
>   392 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |  ^~~~~~~~~~~~~~~~~~~
> ./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
>    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>       |                                     ^~~~~~~~~~~~~~~~~~
> ./include/linux/build_bug.h:59:21: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
>    59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
>       |                     ^~~~~~~~~~~~~~~~
> ./include/linux/huge_mm.h:319:28: note: in expansion of macro ‘BUILD_BUG’
>   319 | #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
>       |                            ^~~~~~~~~
> ./include/linux/huge_mm.h:115:26: note: in expansion of macro ‘HPAGE_PMD_SHIFT’
>   115 | #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
>       |                          ^~~~~~~~~~~~~~~
> mm/compaction.c:64:32: note: in expansion of macro ‘HPAGE_PMD_ORDER’
>    64 | #define COMPACTION_HPAGE_ORDER HPAGE_PMD_ORDER
>       |                                ^~~~~~~~~~~~~~~
> mm/compaction.c:1898:28: note: in expansion of macro ‘COMPACTION_HPAGE_ORDER’
>  1898 |    extfrag_for_order(zone, COMPACTION_HPAGE_ORDER);
>       |                            ^~~~~~~~~~~~~~~~~~~~~~
> make[1]: *** [scripts/Makefile.build:281: mm/compaction.o] Error 1
> make: *** [Makefile:1764: mm] Error 2
> 

What about doing this:

diff --git a/mm/compaction.c b/mm/compaction.c
index 0d4f91dfb801..ac2030814edb 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -60,7 +60,7 @@ static const int HPAGE_FRAG_CHECK_INTERVAL_MSEC = 500;
  * calculates external fragmentation, which is used as
  * the "fragmentation score" of a node/zone.
  */
-#if defined HPAGE_PMD_ORDER
+#if defined CONFIG_TRANSPARENT_HUGEPAGE
 #define COMPACTION_HPAGE_ORDER	HPAGE_PMD_ORDER
 #elif defined HUGETLB_PAGE_ORDER
 #define COMPACTION_HPAGE_ORDER	HUGETLB_PAGE_ORDER

?

-- 
  Best regards,
    Oleksandr Natalenko (post-factum)
    Principal Software Maintenance Engineer