Hello Matthew. Matthew Wilcox - 24.11.17, 02:16: > ====== > XArray > ====== > > Overview > ======== > > The XArray is an array of ULONG_MAX entries. Each entry can be either > a pointer, or an encoded value between 0 and LONG_MAX. It is efficient > when the indices used are densely clustered; hashing the object and > using the hash as the index will not perform well. A freshly-initialised > XArray contains a NULL pointer at every index. There is no difference > between an entry which has never been stored to and an entry which has most > recently had NULL stored to it. I am no kernel developer (just provided a tiny bit of documentation a long time ago)… but on reading into this, I missed: What is it about? And what is it used for? "Overview" appears to be already a description of the actual implementation specifics, instead of… well an overview. Of course, I am sure you all know what it is for… but someone who wants to learn about the kernel is likely to be confused by such a start. Thanks, -- Martin -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href