On 11/21, Jaegeuk Kim wrote: > On 11/21, Matthew Wilcox wrote: > > On Fri, Nov 21, 2025 at 04:46:14AM +0000, Jaegeuk Kim wrote: > > > On 11/21, Matthew Wilcox wrote: > > > > On Fri, Nov 21, 2025 at 03:27:18AM +0000, Jaegeuk Kim wrote: > > > > > This patch introduces a new POSIX_FADV_MLOCK which 1) invalidates the > > > > > range of > > > > > cached pages, 2) sets the mapping as inaccessible, 3) > > > > > POSIX_FADV_WILLNEED loads > > > > > pages directly to the inaccessible mapping. > > > > > > > > ... what? > > > > > > > > This seems like something which is completely different from mlock(). > > > > So it needs a different name. > > > > > > > > But I don't understand the point of this, whatever it's called. Need > > > > more information. > > > > > > So, the sequence that I'd like to optimize is mmap(MAP_POPULATE) followed > > > by mlock(). For example, mmap() takes 1 second to load 4GB data, and > > > mlock() > > > takes 330ms additionally in order to migrate all the pages into > > > inaccessible > > > map, IIUC. > > > > Oh, so the MLOCK part is right, but the inaccessible() part is wrong. > > Inaccessible is special weird guest_memfd crap that has all kinds of > > side-effects that you don't want. > > > > Wouldn't you get the same effect by calling mlock2(MLOCK_ONFAULT) and > > then calling readahead() for the desired range? > > Oh, thank you. Let me try.
After checking the code and experiment, I don't think that gives what we need. That flag skips populate_vma_page_range only, but we need to allocate pages in the inaccessible mapping and fill the pages afterwards. _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
