Sergio López, le Tue 03 Apr 2012 00:00:02 +0200, a écrit : > 2012/4/2 Samuel Thibault <[email protected]>: > > Sergio Lopez, le Mon 02 Apr 2012 17:09:08 +0200, a écrit : > >> El Mon, 02 Apr 2012 00:23:03 +0300 > >> Maksym Planeta <[email protected]> escribió: > >> > This function allows user advise the kernel about how to handle paging > >> > input/output in specified memory range. There are several behaviors, > >> > like RANDOM, NORMAL, SEQUENTIAL, WILLNEED and DONTNEED. From the page > >> > fault handler's point of view these behaviors differ only in size of > >> > memory chunk that will be read ahead. > >> > >> I don't think the kernel should be the one to be advised, but the > >> filesystem translators. These are the ones who really know current and > >> future (as they control most of the operations) state of the object, > > > > Do they really? We discussed about it with neal a long time ago, and we > > believed that Mach was at a better position, because it knows about > > each and every mapping. Say for instance that two processes map the same > > file, and access it concurrently, but in a different way. AIUI, the > > translators will get data requests without indication of what mapping is > > pulling it, and thus no correlation between them, thus seemingly > > random.
I realize that I was talking for read-ahead, which has not much to do with cluster size. Samuel
