On Thu, 15 Mar 2007 22:49:23 +0100 Andrea Arcangeli <[EMAIL PROTECTED]> wrote:
> On Thu, Mar 15, 2007 at 11:07:35AM -0800, Andrew Morton wrote: > > > On Thu, 15 Mar 2007 01:22:45 -0400 (EDT) Ashif Harji <[EMAIL PROTECTED]> > > > wrote: > > > I still think the simple fix of removing the > > > condition is the best approach, but I'm certainly open to alternatives. > > > > Yes, the problem of falsely activating pages when the file is read in small > > hunks is worse than the problem which your patch fixes. > > Really? I would have expected all performance sensitive apps to read > in >=PAGE_SIZE chunks. And if they don't because they split their > dataset in blocks (like some database), it may not be so wrong to > activate those pages that have two "hot" blocks more aggressively than > those pages with a single hot block. But the problem which is being fixed here is really obscure: an application repeatedly reading the first page and only the first page of a file, always via the same fd. I'd expect that the sub-page-size read scenarion happens heaps more often than that, especially when dealing with larger PAGE_SIZEs. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
