On 11/02/26 at 06:46pm, Ridong Chen wrote: > > > On 11/2/2026 9:37 AM, Baoquan He wrote: > > On 10/31/26 at 05:00pm, Ridong Chen wrote: > > > From: Ridong Chen <[email protected]> > > > > > > Move include/trace/events/vmscan.h to mm/trace_vmscan.h so that the > > > tracepoints can be extended to reference vmscan-internal structures such > > > as struct scan_control, which is not visible outside mm/. This mirrors > > > what several other subsystems already do with their trace headers (e.g. > > > fs/fuse/fuse_trace.h, fs/gfs2/trace_gfs2.h, fs/lockd/trace.h). As they > > > do, set TRACE_INCLUDE_PATH to "." and add mm/ to the include path of > > > vmscan.o, the only user that defines CREATE_TRACE_POINTS. > > > > > > No functional change. > > > > > > Signed-off-by: Ridong Chen <[email protected]> > > > Reviewed-by: Barry Song <[email protected]> > > > --- > > > MAINTAINERS | 2 ++ > > > mm/Makefile | 1 + > > > mm/shrinker.c | 2 +- > > > include/trace/events/vmscan.h => mm/trace_vmscan.h | 4 ++++ > > > mm/vmscan.c | 2 +- > > > 5 files changed, 9 insertions(+), 2 deletions(-) > > > rename include/trace/events/vmscan.h => mm/trace_vmscan.h (99%) > > > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > > index aaf2825ac945..2ad01107fa05 100644 > > > --- a/MAINTAINERS > > > +++ b/MAINTAINERS > > > @@ -17653,6 +17653,7 @@ F: > > > Documentation/admin-guide/mm/multigen_lru.rst > > > F: Documentation/mm/multigen_lru.rst > > > F: include/linux/mm_inline.h > > > F: include/linux/mmzone.h > > > +F: mm/trace_vmscan.h > > > F: mm/vmscan.c > > > F: mm/workingset.c > > > @@ -17802,6 +17803,7 @@ R: Shakeel Butt <[email protected]> > > > R: Lorenzo Stoakes <[email protected]> > > > L: [email protected] > > > S: Maintained > > > +F: mm/trace_vmscan.h > > > F: mm/vmscan.c > > > F: mm/workingset.c > > > diff --git a/mm/Makefile b/mm/Makefile > > > index 2a3ec53d62ee..277b97f7f8d7 100644 > > > --- a/mm/Makefile > > > +++ b/mm/Makefile > > > @@ -32,6 +32,7 @@ KCOV_INSTRUMENT_vmstat.o := n > > > KCOV_INSTRUMENT_failslab.o := n > > > CFLAGS_init-mm.o += -Wno-override-init > > > +CFLAGS_vmscan.o += -I$(src) > > > > One nit: > > > > Does it really need the above line? It affects mm/shrinker.c too, did your > > shrinker.o building fail? > > > > Seems it's redundant because kbuild adds -I$(src) -I$(obj) for every object > > in the directory since commit cdd750bfb1f7 ("kbuild: remove 'addtree' and > > 'flags' magic for header search paths"). Please correct me if I am > > wrong. > > > > Hi Baoquan, > > Thanks for the review. > > The line is needed for vmscan.o, and mm/shrinker.c is fine without it, > because the two files include trace_vmscan.h in different ways. > > mm/shrinker.c only does a plain #include "trace_vmscan.h". The lookup > starts from mm/, where the header lives, so no -I is needed. > > mm/vmscan.c defines CREATE_TRACE_POINTS before including the header. > In that case <trace/define_trace.h>, included at the end of > trace_vmscan.h, includes the header again to generate the tracepoint > definitions: > > #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) /* -> "./trace_vmscan.h" */ > > This #include is in include/trace/define_trace.h, so the lookup starts > from include/trace/ and only finds the header through -I. Without the > flag, vmscan.o fails to build: > > ./include/trace/define_trace.h:118:42: fatal error: ./trace_vmscan.h: No > such file or directory > > As for cdd750bfb1f7, it doesn't add -I$(src) for every build. kbuild > only adds -I$(src) -I$(obj) automatically when building with O= > (see "ifdef building_out_of_srctree" in scripts/Makefile.lib). So > with O= the line is indeed redundant and vmscan.o builds fine without > it, but a plain in-tree "make" fails with the error above. The > explicit flag keeps both working. > > To be honest, I had the same worry at first: I thought every .c file > that includes the header would need a Makefile change. That's why v3 > used a relative TRACE_INCLUDE_PATH (../../mm) instead. Steven corrected > me and pointed out that the proper way is TRACE_INCLUDE_PATH "." plus > -I$(src) for the one object that defines CREATE_TRACE_POINTS [1]. That > turned out to need only this one line. Thanks again to Steven for > that.
You are right, my nit was wrong. Learned it from you, thanks for the detailed explanation. > > [1] https://lore.kernel.org/all/[email protected]/ > > > > Other than the nit, this patch looks good to me, > > > > Reviewed-by: Baoquan He <[email protected]> > > > > Thanks. > > > mmu-y := nommu.o > > > mmu-$(CONFIG_MMU) := highmem.o memory.o mincore.o \ > > > diff --git a/mm/shrinker.c b/mm/shrinker.c > > > index 4fb424e721bc..4fbdade6d2f6 100644 > > > --- a/mm/shrinker.c > > > +++ b/mm/shrinker.c > > > @@ -3,7 +3,7 @@ > > > #include <linux/rwsem.h> > > > #include <linux/shrinker.h> > > > #include <linux/rculist.h> > > > -#include <trace/events/vmscan.h> > > > +#include "trace_vmscan.h" > > > #include "internal.h" > > > diff --git a/include/trace/events/vmscan.h b/mm/trace_vmscan.h > > > similarity index 99% > > > rename from include/trace/events/vmscan.h > > > rename to mm/trace_vmscan.h > > > index 8a872990b4be..ad90f0e9bf2e 100644 > > > --- a/include/trace/events/vmscan.h > > > +++ b/mm/trace_vmscan.h > > > @@ -648,4 +648,8 @@ TRACE_EVENT(mm_vmscan_kswapd_clear_hopeless, > > > #endif /* _TRACE_VMSCAN_H */ > > > /* This part must be outside protection */ > > > +#undef TRACE_INCLUDE_FILE > > > +#undef TRACE_INCLUDE_PATH > > > +#define TRACE_INCLUDE_PATH . > > > +#define TRACE_INCLUDE_FILE trace_vmscan > > > #include <trace/define_trace.h> > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > > index 9959ca158ce8..79d2d614afd0 100644 > > > --- a/mm/vmscan.c > > > +++ b/mm/vmscan.c > > > @@ -71,7 +71,7 @@ > > > #include "swap.h" > > > #define CREATE_TRACE_POINTS > > > -#include <trace/events/vmscan.h> > > > +#include "trace_vmscan.h" > > > struct scan_control { > > > /* How many pages shrink_list() should reclaim */ > > > -- > > > 2.43.0 > > > > > -- > Best regards > Ridong >
