On Fri, Apr 20, 2012 at 10:58 AM, Ted Ts'o <tytso@xxxxxxx> wrote: > On Fri, Apr 20, 2012 at 06:42:08PM +0400, James Bottomley wrote: >> >> I'm not at all wedded to O_HOT and O_COLD; I think if we establish a >> hint hierarchy file->page cache->device then we should, of course, >> choose the best API and naming scheme for file->page cache. The only >> real point I was making is that we should tie in the page cache, and >> currently it only knows about "hot" and "cold" pages. > > The problem is that "hot" and "cold" will have different meanings from > the perspective of the file system versus the page cache. The file > system may consider a file "hot" if it is accessed frequently --- > compared to the other 2 TB of data on that HDD. The memory subsystem > will consider a page "hot" compared to what has been recently accessed > in the 8GB of memory that you might have your system. Now consider > that you might have a dozen or so 2TB disks that each have their "hot" > areas, and it's not at all obvious that just because a file, or even > part of a file is marked "hot", that it deserves to be in memory at > any particular point in time. So, this have intentionally different meanings I have no seen a reason why fs uses hot/cold words. It seems to bring a confusion. But I don't know full story of this feature and I might be overlooking something. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
