From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f71.google.com (mail-oi0-f71.google.com [209.85.218.71]) by kanga.kvack.org (Postfix) with ESMTP id 516C28E0001 for ; Mon, 17 Sep 2018 00:37:34 -0400 (EDT) Received: by mail-oi0-f71.google.com with SMTP id v4-v6so17078349oix.2 for ; Sun, 16 Sep 2018 21:37:34 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id 7-v6si6819096oik.113.2018.09.16.21.37.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 16 Sep 2018 21:37:32 -0700 (PDT) Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w8H4YenF122538 for ; Mon, 17 Sep 2018 00:37:32 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0b-001b2d01.pphosted.com with ESMTP id 2mhx1wbtgt-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 17 Sep 2018 00:37:32 -0400 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 17 Sep 2018 05:37:30 +0100 Date: Mon, 17 Sep 2018 07:37:24 +0300 From: Mike Rapoport Subject: Re: KSM not working in 4.9 Kernel References: <20180916153237.GC15699@rapoport-lnx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Message-Id: <20180917043724.GA12866@rapoport-lnx> Sender: owner-linux-mm@kvack.org List-ID: To: Pintu Kumar Cc: open list , Russell King - ARM Linux , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org 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 > > > > > sleep(1); > > > } > > > printf("Done....press ^C\n"); > > > > > > pause(); > > > > > > return 0; > > > } > > > > > > > > > > > > Thanks, > > > Pintu > > > > > > > -- > > Sincerely yours, > > Mike. > > > -- Sincerely yours, Mike.