On Wed, 20 May 2020 at 09:31, Valdis Klētnieks <valdis.kletnieks@xxxxxx> wrote: > > On Tue, 19 May 2020 22:33:15 +0530, Pintu Agarwal said: > > > > Below are some data taken from a small embedded arm32 device with 512MB RAM: > > > > > > > Sorry, I forgot to mention the kernel version. Here it is 3.18 Kernel > > That's a kernel from 2014. You don't seriously expect us to remember how > all those counters worked back then, do you? > Actually I don't care about the kernel version. This was just for reference. I know it is weird to manually arrive a MemTotal from the values of meminfo. But I am actually looking for general formula. I could get some of the answers by tracing the kernel code for each counters. But still there are some gaps which I want to clarify. As I see there are several ways to total it: i.e; (PSS way), (Buffers, Cached), (Active, Inactive) According to me, MemTotal = MemFree + Active + Inactive + SwapCached + Mapped + Shmem + Slab + KernelStack + PageTables + (Init Freed from boot) + (alloc pages) + (min_free_bytes + user_reserve_bytes) Did I miss anything here ? With this I could arrive to some result, but I have some doubts: * Is Mapped already included in Active/Inactive (file) ? Because mapped is coming from NR_FILE_MAPPED. ==> I see that it is accounted from mm/rmap.c * Do we also need to incude VmallocUsed here ? I see in some cases people include it too. ==> But I think vmalloc internally calls kmalloc and use page tables, so it should be already accounted in Slab and PageTables ?? ==> Do I still need to include these values from /proc/vmallocinfo ?? * Is it valid to include min_free_kbytes and user_reserve_kbytes here ? Its kind of reserve for internal purpose but still it contributes to the total. * Is kernel internal allocation (alloc_pages) statistics accounted somewhere ? ==> I can see that some counters like (pgalloc_normal, etc. and pgfree) are available as part of /proc/vmstat ===> But this is like overall allocation and free stats. * Apart from these, do we also need to consider Graphics/3D allocation separately ? Thanks, Pintu _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
