Hi, I am trying to understand the sparsemem implementation in linux for NUMA/multiple node systems. >From the available documentation and the sparsemem patches, I am able to make out that sparsemem divides memory into different sections and if the whole section contains a hole then its marked as invalid section and if some pages in a section form a hole then those pages are marked reserved. My issue is that this classification, I am not able to map it to the code. e.g. from arch specific code, we call memory_present() to prepare a list of sections in a particular node. but unable to find where exactly some sections are marked invalid because they contain a hole. Can somebody tell me where in the code are we identifying sections as invalid and where we are marking pages as reserved. Pls correct me, if I am wrong in my understanding. Also, If theres any article or writeup on sparsemem, pls point me to that. I apologize, if I have posted this mail on the wrong mailing list, in that case, pls let me know the correct forum to ask this question. Regards, Naren -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>