From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx174.postini.com [74.125.245.174]) by kanga.kvack.org (Postfix) with SMTP id C673F6B005D for ; Mon, 19 Nov 2012 05:06:56 -0500 (EST) Received: by mail-da0-f41.google.com with SMTP id e20so595344dak.14 for ; Mon, 19 Nov 2012 02:06:56 -0800 (PST) Date: Mon, 19 Nov 2012 02:06:48 -0800 (PST) From: Hugh Dickins Subject: Re: [patch 1/2 v2]swap: add a simple buddy allocator In-Reply-To: <20121119075943.GA17405@kernel.org> Message-ID: References: <20121119075943.GA17405@kernel.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Shaohua Li Cc: linux-mm@kvack.org, akpm@linux-foundation.org, minchan@kernel.org, riel@redhat.com On Mon, 19 Nov 2012, Shaohua Li wrote: > > Changes from V1 to V2: > 1. free cluster is added to a list, which makes searching cluster more efficient > 2. only enable the buddy allocator for SSD. Oh. My fault, not yours at all, but I wish I'd known this was coming. I spent today testing and fixing (a couple of hangs in discard 2/2) V1, was about to send you a patch, but looks like none of it relevant to V2. It's nice work you've done, I thoroughly approve of V1 (very minor mods), but it'll take me a few more days to get around to looking at V2, sorry. Though, it may be my ignorance, I entirely fail to see what this has to do with a buddy allocator: you've speeded up scan_swap_map()'s search for a cluster by adding an additional cluster map, then extended that neatly for a much better discard implementation. Good work yes, but a buddy allocator?? Thanks! Hugh -- 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