From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 20 Apr 2007 15:06:18 -0700 From: Andrew Morton Subject: Re: [PATCH] lazy freeing of memory through MADV_FREE Message-Id: <20070420150618.179d31a4.akpm@linux-foundation.org> In-Reply-To: <462932BE.4020005@redhat.com> References: <46247427.6000902@redhat.com> <20070420135715.f6e8e091.akpm@linux-foundation.org> <462932BE.4020005@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: linux-kernel , linux-mm List-ID: On Fri, 20 Apr 2007 17:38:06 -0400 Rik van Riel wrote: > Andrew Morton wrote: > > > I've also merged Nick's "mm: madvise avoid exclusive mmap_sem". > > > > - Nick's patch also will help this problem. It could be that your patch > > no longer offers a 2x speedup when combined with Nick's patch. > > > > It could well be that the combination of the two is even better, but it > > would be nice to firm that up a bit. > > I'll test that. Thanks. > > I do go on about that. But we're adding page flags at about one per > > year, and when we run out we're screwed - we'll need to grow the > > pageframe. > > If you want, I can take a look at folding this into the > ->mapping pointer. I can guarantee you it won't be > pretty, though :) Well, let's see how fugly it ends up looking? > > - I need to update your patch for Nick's patch. Please confirm that > > down_read(mmap_sem) is sufficient for MADV_FREE. > > It is. MADV_FREE needs no more protection than MADV_DONTNEED. > > > Stylistic nit: > > > >> + if (PageLazyFree(page) && !migration) { > >> + /* There is new data in the page. Reinstate it. */ > >> + if (unlikely(pte_dirty(pteval))) { > >> + set_pte_at(mm, address, pte, pteval); > >> + ret = SWAP_FAIL; > >> + goto out_unmap; > >> + } > > > > The comment should be inside the second `if' statement. As it is, It > > looks like we reinstate the page if (PageLazyFree(page) && !migration). > > Want me to move it? I did that, thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org