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Is anyone usefully using the existing instrumentation? >> What is to be gained by expanding it further? What is the case for >> adding this code? >> >> I don't recall hearing of anyone using the existing debug >> instrumentation so perhaps we should remove it! > Hi Andrew, this was discussed in [1]. In short, I use the > debug files to test change in submit patchset [1]. The > wb_monitor.py is suggested by Tejun in [2] to improve > visibility of writeback. > I use the debug files to test change in [1]. The wb_monitor.py is suggested by Tejun > in [2] to improve visibility of writeback. >> >> Also, I hit a build error and a pile of warnings with an arm >> allnoconfig build. With arm allnoconfig build on uptodated mm-unstable branch, I don't hit any build error but only some warnings as following: ... mm/page-writeback.c: In function ¡®cgwb_calc_thresh¡¯: mm/page-writeback.c:906:13: warning: ¡®writeback¡¯ is used uninitialized in this function [-Wuninitialized] 906 | mdtc.dirty += writeback; | ~~~~~~~~~~~^~~~~~~~~~~~ In file included from ./include/linux/kernel.h:28, from mm/page-writeback.c:15: ./include/linux/minmax.h:46:54: warning: ¡®filepages¡¯ is used uninitialized in this function [-Wuninitialized] 46 | #define __cmp(op, x, y) ((x) __cmp_op_##op (y) ? (x) : (y)) | ^ mm/page-writeback.c:898:16: note: ¡®filepages¡¯ was declared here 898 | unsigned long filepages, headroom, writeback; | ^~~~~~~~~ In file included from ./include/linux/kernel.h:28, from mm/page-writeback.c:15: ./include/linux/minmax.h:46:54: warning: ¡®headroom¡¯ is used uninitialized in this function [-Wuninitialized] 46 | #define __cmp(op, x, y) ((x) __cmp_op_##op (y) ? (x) : (y)) | ^ mm/page-writeback.c:898:27: note: ¡®headroom¡¯ was declared here 898 | unsigned long filepages, headroom, writeback; | ^~~~~~~~ ... The only reason I can think of is that I also apply patchset [1] for build. I mentioned patchset [1] in cover letter but I forgot to notify the dependency to the patchset. If this is the reason to blame for buidl error, I will send a new set based on mm-unstable in next version. Thanks, Kemeng [1] https://lore.kernel.org/lkml/20240123183332.876854-1-shikemeng@huaweicloud.com/T/#mc6455784a63d0f8aa1a2f5aff325abcdf9336b76 >> > Sorry for this, I only tested on x86. I will look into this and > fix the build problem in next version. > > [1] https://lore.kernel.org/lkml/44e3b910-8b52-5583-f8a9-37105bf5e5b6@huaweicloud.com/ > [2] https://lore.kernel.org/lkml/a747dc7d-f24a-08bd-d969-d3fb35e151b7@huaweicloud.com/ > [3] https://lore.kernel.org/lkml/ZcUsOb_fyvYr-zZ-@slm.duckdns.org/ >