[Crash-utility] [BUG FIXED]fix bug of CACHED in kmem -i show memory

>>>> (gdb) p nr_swapper_spaces >>>> $4 = <optimized out> >>> Thank you folks, for the various information. >>> >>> Apparently the data of nr_swapper_spaces exists in the kernel, but its >>> symbol does not exist. I think this means that we cannot calculate the >>> number of pages from swapper_spaces[] with such a debuginfo, because we >>> cannot get the array size of a swapper_spaces entry. >> That's correct, Kazu. >> >> >>> So I'd like to go with Johan's patch. >>> >>> cc -c -g -DX86_64 -DLZO -DSNAPPY -DGDB_10_2 memory.c -Wall -O2 >>> -Wstrict-prototypes -Wmissing-prototypes -fstack-protector >>> -Wformat-security >>> memory.c: In function dump_kmeminfo: >>> memory.c:8612:50: warning: pointer targets in passing argument 2 of >>> dump_vm_stat differ in signedness [-Wpointer-sign] >>> 8612 | if (dump_vm_stat("NR_SWAPCACHE", >>> &swapper_space_nrpages, 0)) { >>> | >>> ^~~~~~~~~~~~~~~~~~~~~~ >>> | | >>> | ulong * {aka >>> long unsigned int *} >>> memory.c:298:33: note: expected long int * but argument is of type ulong >>> * {aka long unsigned int *} >>> 298 | static int dump_vm_stat(char *, long *, ulong); >>> | ^~~~~~ >>> >>> So with the following, >>> >>> - ulong swapper_space_nrpages; >>> + long swapper_space_nrpages; >> Looks good. Maybe the patch log also needs to be improved a little bit. >> >> Although the checking of kernel version looks not very good, seems no >> better way. > hmm, this sounds strange. My ack is for Johan's patch (attached), which Ah, I did not see the attached patch. Thank you for pointing out this issue, Kazu. > does not have kernel version check, is this ok? sorry for confusing. Sounds good idea if there is no kernel version check. I still have one question: the following two commits were introduced separately in kernel 5.12 and 4.11. b6038942480e ("mm: memcg: add swapcache stat for memcg v2") 4b3ef9daa4fc ("mm/swap: split swap cache into 64MB trunks") It indicates that the attached patch may not work well between kernel 4.11 and 5.12, is it possible to encounter the similar issue(the nr_swapper_spaces may be optimized away)?