On Thu, Mar 15, 2007 at 05:44:01PM +0000, Hugh Dickins wrote: > On Thu, 15 Mar 2007, Nick Piggin wrote: > > On Thu, Mar 15, 2007 at 11:56:59AM -0400, Chuck Ebbert wrote: > > > Ashif Harji wrote: > > > > > > > > This patch unconditionally calls mark_page_accessed to prevent pages, > > > > especially for small files, from being evicted from the page cache > > > > despite frequent access. > > > > > > > > Signed-off-by: Ashif Harji <[EMAIL PROTECTED]> > > Yeah, yeah, I'm not a real mman, I don't have my own patch and > website for this ;) but I'm old, let me mumble some history... > > Ashif's patch would take us back to 2.4.10 when mark_page_accessed > was introduced: in 2.4.11 someone (probably Andrea) immediately > added a !offset || !filp->f_reada condition on it there, which > remains in 2.4 to this day. That _probably_ means that Ashif's > patch is suboptimal, and that your !offset patch is good. > > f_reada went away in 2.5.8, and the !offset condition remained > until 2.6.11, when Miquel (CC'ed) replaced it by today's prev_index > condition. His changelog entry appended below. Since it's Miquel > who removed the !offset condition, he should be consulted on its > reintroduction.
Yeah I did go back and check up on that changelog, because I knew we had a !offset check there at one stage, which is immune to this problem (or at least can handle it a little better). I suspect that Miquel was probably more interested in _increasing_ mark_page_accessed coverage with his new condition than restricting it from the !offset cases. Thanks for digging it up and posting here, though. - 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/
