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b=lMRg/l/X13Y/iSRcAsT5Zn/Sofzb4N6k2MmNKq+nd7Ut6VdDFbMXMeGxT58R0LG8o o8fhkG9PzUzRy/PvjOJspXVchGGJCKj8uUD7oCmXpuMeg2Rl/P6xUYGBJtHF0UwnrR Xi4S5YT1SorcgV+cGeps/so/PTTNxLb2XUqf4kEk= Date: Tue, 7 Apr 2026 14:21:42 -0700 From: Andrew Morton To: "Lorenzo Stoakes (Oracle)" Cc: Hugh Dickins , xu.xin16@zte.com.cn, david@kernel.org, chengming.zhou@linux.dev, wang.yaxin@zte.com.cn, yang.yang29@zte.com.cn, Michel Lespinasse , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/2] ksm: Optimize rmap_walk_ksm by passing a suitable address range Message-Id: <20260407142142.cd093ccafe62eaaadb5cf11c@linux-foundation.org> In-Reply-To: References: <20260212193045556CbzCX8p9gDu73tQ2nvHEI@zte.com.cn> <02e1b8df-d568-8cbb-b8f6-46d5476d9d75@google.com> <20260405140132.3a518740c6c1d68843f44aaf@linux-foundation.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: F0E2080008 X-Stat-Signature: 4i5b94mcf48wnrruszxocamya4knw8on X-Rspam-User: X-HE-Tag: 1775596904-100978 X-HE-Meta: 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 azMy5izs Wze1LkJUhsKCsL7SgGn2vjVKiWmvxEx86A+OH+vviPRHaTe1jNE5KnZcxDK+6x+WxKDNL/V9lsPGzGyqKdIeLIn00bjjyulmlb++TYWBzTmS0T4GKxlSGxe3NA0GYryF4JlFxLzsO6zq92frQbErkmywWceoBRYI1xqrBrikXDL7dGGuF6ixwuUXSw5bM36QSciFfov9tJGNM7w1SMle6E/yyNO610Lesbvw3+dQ6WhzXeEsjQKlJrWc6hpbpzVxqhSXtCRQVOwXM5Ru2XtfrKseelFFgD4+S8YA33/etKbmfBUD3naAlw7rQTflOvoVPvViUng7DSSuEVucI0efSt+o2KTwQwnpYH3rcvVhZsMpUeGTGGk7/xbAHmkc+uITUlHqJ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 7 Apr 2026 10:43:12 +0100 "Lorenzo Stoakes (Oracle)" wrote: > > Thanks, Hugh. Administreevia: > > > > I've removed this patch from the mm-stable branch and I reworked its > > [1/2] "ksm: initialize the addr only once in rmap_walk_ksm" to be > > presented as a singleton patch. > > > > For now I've restaged this patch ("ksm: optimize rmap_walk_ksm by > > passing a suitable address range") at the tail of the mm-unstable > > branch and I'll enter wait-and-see mode. > > > > Given we're at -rc7 now, I think we should delay this patch until 7.2, unless > I'm much mistaken wrt Hugh's concerns. > > I'm concerned this is a subtle way of breaking things so we really want to be > confident. > > We should also bundle up the test at > https://lore.kernel.org/all/20260407140805858ViqJKFhfmYSfq0FynsaEY@zte.com.cn/ > with this patch (should we find it's ok) as a separate series. > > Really overall I think safest to yank until 7.2 honestly. OK. But let's not lose sight of those potential efficiency gains: Time_ms Nr_iteration_total Skip_addr_out_of_range Skip_mm_mismatch Before: 228.65 22169 22168 0 After : 0.396 3 0 2