Messages in this thread Patch in this message | | | From | "Zi Yan" <> | Subject | Re: [PATCH v9 05/10] mm: thp: enable thp migration in generic path | Date | Wed, 19 Jul 2017 22:54:04 -0400 |
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On 19 Jul 2017, at 16:59, Andrew Morton wrote:
> On Wed, 19 Jul 2017 14:39:43 -0400 "Zi Yan" <zi.yan@cs.rutgers.edu> > wrote: > >> On 19 Jul 2017, at 4:04, kbuild test robot wrote: >> >>> Hi Zi, >>> >>> [auto build test WARNING on mmotm/master] >>> [also build test WARNING on v4.13-rc1 next-20170718] >>> [if your patch is applied to the wrong git tree, please drop us a >>> note to help improve the system] >>> >>> url: >>> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2F0day-ci%2Flinux%2Fcommits%2FZi-Yan%2Fmm-page-migration-enhancement-for-thp%2F20170718-095519&data=02%7C01%7Czi.yan%40cs.rutgers.edu%7Ca711ac47d4c0436ef66f08d4ce7cf30c%7Cb92d2b234d35447093ff69aca6632ffe%7C1%7C0%7C636360483431631457&sdata=NpxRpWbxe6o56xDJYpw1K6wgQo11IPCAbG2tE8l%2BU6E%3D&reserved=0 >>> base: git://git.cmpxchg.org/linux-mmotm.git master >>> config: xtensa-common_defconfig (attached as .config) >>> compiler: xtensa-linux-gcc (GCC) 4.9.0 >>> reproduce: >>> wget >>> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fraw.githubusercontent.com%2F01org%2Flkp-tests%2Fmaster%2Fsbin%2Fmake.cross&data=02%7C01%7Czi.yan%40cs.rutgers.edu%7Ca711ac47d4c0436ef66f08d4ce7cf30c%7Cb92d2b234d35447093ff69aca6632ffe%7C1%7C0%7C636360483431631457&sdata=rBCfu0xUg3v%2B8r%2Be2tsiqRcqw%2FEZSTa4OtF0hU%2FqMbc%3D&reserved=0 >>> -O ~/bin/make.cross >>> chmod +x ~/bin/make.cross >>> # save the attached .config to linux build tree >>> make.cross ARCH=xtensa >>> >>> All warnings (new ones prefixed by >>): >>> >>> In file included from mm/vmscan.c:55:0: >>> include/linux/swapops.h: In function 'swp_entry_to_pmd': >>>>> include/linux/swapops.h:220:2: warning: missing braces around >>>>> initializer [-Wmissing-braces] >>> return (pmd_t){ 0 }; >>> ^ >>> include/linux/swapops.h:220:2: warning: (near initialization for >>> '(anonymous).pud') [-Wmissing-braces] >>> >>> vim +220 include/linux/swapops.h >>> >>> 217 >>> 218 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) >>> 219 { >>>> 220 return (pmd_t){ 0 }; >>> 221 } >>> 222 >> >> It is a GCC 4.9.0 bug: >> https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgcc.gnu.org%2Fbugzilla%2Fshow_bug.cgi%3Fid%3D53119&data=02%7C01%7Czi.yan%40cs.rutgers.edu%7C07c903c4f1444958942508d4cee90ca7%7Cb92d2b234d35447093ff69aca6632ffe%7C1%7C0%7C636360947714283172&sdata=84%2BXG7hglTCsTjGA8G3jyL7%2BFupkQaMkjAwzofffA5A%3D&reserved=0 >> >> Upgrading GCC can get rid of this warning. > > I think there was a workaround for this, but I don't recall what it > was. > > This suppressed the warning: > > --- a/include/linux/swapops.h~a > +++ a/include/linux/swapops.h > @@ -217,7 +217,7 @@ static inline swp_entry_t pmd_to_swp_ent > > static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) > { > - return (pmd_t){ 0 }; > + return (pmd_t){}; > } > > static inline int is_pmd_migration_entry(pmd_t pmd) > > But I don't know if this is the approved workaround and I don't know > what it will do at runtime! > > But we should fix this. Expecting zillions of people to update their > compiler version isn't nice.
How about this one?
--- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -219,7 +219,7 @@ static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) { - return (pmd_t){ 0 }; + return __pmd(0); }
static inline int is_pmd_migration_entry(pmd_t pmd)
No warning or error was present during i386 kernel compilations with gcc-4.9.3 or gcc-6.4.0. i386 gcc should share the same front-end as xtensa-linux-gcc.
__pmd() should be the standard way of making pmd entries, right?
-- Best Regards Yan Zi
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