From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vk1-f199.google.com (mail-vk1-f199.google.com [209.85.221.199]) by kanga.kvack.org (Postfix) with ESMTP id BA42A8E0001 for ; Mon, 17 Sep 2018 02:16:30 -0400 (EDT) Received: by mail-vk1-f199.google.com with SMTP id h81-v6so2283768vke.13 for ; Sun, 16 Sep 2018 23:16:30 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id e11-v6sor3691314vsc.25.2018.09.16.23.16.29 for (Google Transport Security); Sun, 16 Sep 2018 23:16:29 -0700 (PDT) MIME-Version: 1.0 References: <20180916153237.GC15699@rapoport-lnx> <20180917043724.GA12866@rapoport-lnx> In-Reply-To: <20180917043724.GA12866@rapoport-lnx> From: Pintu Kumar Date: Mon, 17 Sep 2018 11:46:17 +0530 Message-ID: Subject: Re: KSM not working in 4.9 Kernel Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: rppt@linux.vnet.ibm.com Cc: open list , Russell King - ARM Linux , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org On Mon, Sep 17, 2018 at 10:07 AM Mike Rapoport wrote: > > On Sun, Sep 16, 2018 at 10:35:17PM +0530, Pintu Kumar wrote: > > On Sun, Sep 16, 2018 at 9:02 PM Mike Rapoport wrote: > > > > > > On Fri, Sep 14, 2018 at 07:58:01PM +0530, Pintu Kumar wrote: > > > > Hi All, > > > > > > > > Board: Hikey620 ARM64 > > > > Kernel: 4.9.20 > > > > > > > > I am trying to verify KSM (Kernel Same Page Merging) functionality on > > > > 4.9 Kernel using "mmap" and madvise user space test utility. > > > > But to my observation, it seems KSM is not working for me. > > > > CONFIG_KSM=y is enabled in kernel. > > > > ksm_init is also called during boot up. > > > > 443 ? SN 0:00 [ksmd] > > > > > > > > ksmd thread is also running. > > > > > > > > However, when I see the sysfs, no values are written. > > > > ~ # grep -H '' /sys/kernel/mm/ksm/* > > > > /sys/kernel/mm/ksm/pages_hashed:0 > > > > /sys/kernel/mm/ksm/pages_scanned:0 > > > > /sys/kernel/mm/ksm/pages_shared:0 > > > > /sys/kernel/mm/ksm/pages_sharing:0 > > > > /sys/kernel/mm/ksm/pages_to_scan:200 > > > > /sys/kernel/mm/ksm/pages_unshared:0 > > > > /sys/kernel/mm/ksm/pages_volatile:0 > > > > /sys/kernel/mm/ksm/run:1 > > > > /sys/kernel/mm/ksm/sleep_millisecs:1000 > > > > > > > > So, please let me know if I am doing any thing wrong. > > > > > > > > This is the test utility: > > > > int main(int argc, char *argv[]) > > > > { > > > > int i, n, size; > > > > char *buffer; > > > > void *addr; > > > > > > > > n = 100; > > > > size = 100 * getpagesize(); > > > > for (i = 0; i < n; i++) { > > > > buffer = (char *)malloc(size); > > > > memset(buffer, 0xff, size); > > > > addr = mmap(NULL, size, > > > > PROT_READ | PROT_EXEC | PROT_WRITE, > > > > MAP_PRIVATE | MAP_ANONYMOUS, > > > > -1, 0); > > > > madvise(addr, size, MADV_MERGEABLE); > > > > > > Just mmap'ing an area does not allocate any physical pages, so KSM has > > > nothing to merge. > > > > > > You need to memset(addr,...) after mmap(). > > > > > > > Yes, I am doing memset also. > > memset(addr, 0xff, size); > > > > But still no effect. > > And I checked LTP test cases. It almost doing the same thing. > > > > I observed that [ksmd] thread is not waking up at all. > > I gave some print inside it, but I could never saw that prints coming. > > I could not find it running either in top command during the operation. > > Is there anything needs to be done, to wakw up ksmd? > > I already set: echo 1 > /sys/kernel/mm/ksm. > > It should be echo 1 > /sys/kernel/mm/ksm/run > Oh yes, sorry for the typo. I tried the same, but still ksm is not getting invoked. Could someone confirm if KSM was working in 4.9 kernel? > > > > > > > > sleep(1); > > > > } > > > > printf("Done....press ^C\n"); > > > > > > > > pause(); > > > > > > > > return 0; > > > > } > > > > > > > > > > > > > > > > Thanks, > > > > Pintu > > > > > > > > > > -- > > > Sincerely yours, > > > Mike. > > > > > > > -- > Sincerely yours, > Mike. >