From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 114D2C43387 for ; Mon, 31 Dec 2018 06:54:31 +0000 (UTC) Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8A3E520B1F for ; Mon, 31 Dec 2018 06:54:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ZkU08+0A" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A3E520B1F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=kernelnewbies-bounces@kernelnewbies.org Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.91) (envelope-from ) id 1gdrSr-0007s7-Ql; Mon, 31 Dec 2018 01:54:17 -0500 Received: from mail-yb1-xb44.google.com ([2607:f8b0:4864:20::b44]) by shelob.surriel.com with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.91) (envelope-from ) id 1gdrSp-0007ry-67 for kernelnewbies@kernelnewbies.org; Mon, 31 Dec 2018 01:54:15 -0500 Received: by mail-yb1-xb44.google.com with SMTP id w6so5928886ybq.1 for ; Sun, 30 Dec 2018 22:54:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=/ZhM4orgAsyhA+WAfXHCm6YnnC//3gOw3FTIhWd6cX4=; b=ZkU08+0A9gwIinlWKBViXWUE3dRDSSNzjpP4FOA7qZZBEDDBXc79rNt7nCtNJPqIow 8dRjExvAzI95n4CykBqXYIp5vg0M9DCPfqVr32SHZ6E4gg6RBpkiz/f/p3dp/XspOtZO DRBEYvEuShyosB99uHzynsVUEWU8pDl1poz927z0atwj6I3Fxl8S2uCGZGSM/G+vNE8p UGy0dVaDQkLNSctmC+YdO+rvSJiTisRv6cl1TFp/YAfErelKoeDkM+srp1K3MTcQCtMJ kgEOZ2kQCu6E1yIdnvuThL3buzF6KjNpRJgppqltGKUj4P7trivTV+eWgEvkNj9CUfxr os7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=/ZhM4orgAsyhA+WAfXHCm6YnnC//3gOw3FTIhWd6cX4=; b=ChXtSlXNsa96u6Reromxvr36x7WOk/zYW6mNr9E6vtMvYohGmHBCfn6IQN0TO570no LsTXEAUDUyPFcnsAo4m/4DBqyc5loIhkrSMMx/JdOPrTOCsETSyno+0Ffw6LNocMijcR wPbEkZlcuDDjRfXeVVtKSqL8SG1eukRwo17zELS6Ik+YRnsuBMcb9R0EYdJKhGsscjR4 uzOvLWPx0ld7i9iw/4E4JNTD9SjrZwimVgjTfuWHogyZkzT8iUYqJfoSMrvaG5Bg3CnX TZIVsmq/OULpENlA6IQ5XIFRPziT9DDBQpsYhCHo+TR7fVDaUAKd3cv6Uk5dhoWHU0cF vZYA== X-Gm-Message-State: AJcUukf2ZW4fwhfOuJBUwbwjmwP37qD9hzMq7F7AS/CU5oIZSEYXOGld pvF6+HD2nLlPj1oUQ9OHT0PjnTBBLIzpLSqiFHy8XA== X-Google-Smtp-Source: ALg8bN6Jw+Sqo5xcY+Otldv2jWM5ANg2qZkJwwzMsBD+A5rBJQpV0wwhxVn2wXwQzTRz8fg9i414YakZDz6jlcFK94A= X-Received: by 2002:a25:748b:: with SMTP id p133mr35829939ybc.188.1546239252236; Sun, 30 Dec 2018 22:54:12 -0800 (PST) MIME-Version: 1.0 References: <2ef41c8f111a94eaaa6082f6168a56fd@amit-agarwal.co.in> <5ac059b588692de67b6eeede673ae5b2@amit-agarwal.co.in> In-Reply-To: <5ac059b588692de67b6eeede673ae5b2@amit-agarwal.co.in> From: Manish Katiyar Date: Sun, 30 Dec 2018 22:54:00 -0800 Message-ID: Subject: Re: Understanding memory fragmentation in Linux kernel To: Amit Agarwal Cc: kernelnewbies X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============2505137717182127751==" Errors-To: kernelnewbies-bounces@kernelnewbies.org --===============2505137717182127751== Content-Type: multipart/alternative; boundary="0000000000005e0f81057e4be123" --0000000000005e0f81057e4be123 Content-Type: text/plain; charset="UTF-8" On Sun, Dec 30, 2018, 10:28 PM Amit Agarwal On 2018-12-31 06:22, Manish Katiyar wrote: > > > How do you know it is because of memory ? If you have sufficient RAM then > it should be able to allocate. Does you application fail with ENOMEM ? > Without knowing the error code from application it's hard to suggest > anything. > > > There is no debugging enabled on site and there is nothing we can do now > to enable it and it is happening in only one site. But from whatever logs I > have, it is failing in calloc. > > I am not requesting help in resolving the issue with application (I will > be able to debug that), but only need help in understanding the memory > fragmentation part. ( I gave details of original problem so that I can > explain what I am trying to understand and wh > Maybe you can try echo m > /proc/sysrq-trigger Or looking at /proc/buddyinfo > > -- > Thanks, > -aka > --0000000000005e0f81057e4be123 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


= On Sun, Dec 30, 2018, 10:28 PM Amit Agarwal <amit@amit-agarwal.co.in wrote:

On 2018-12-31 06:22, Manish Katiyar wrote:


How do you know it is because of memory ? If you have suf= ficient RAM then it should be able to allocate. Does you application fail w= ith ENOMEM ?
Without knowing the error code from application it's = hard to suggest anything.
=C2=A0
There is no debugging enabled on site and there is nothing we can do n= ow to enable it and it is happening in only one site. But from whatever log= s I have, it is failing in calloc.
=C2=A0
I am not requesting help in resolving the issue with application (I wi= ll be able to debug that), but only need help in understanding the memory f= ragmentation part. ( I gave details of original problem so that I can expla= in what I am trying to understand and wh

Maybe you can try

echo m > /proc/sysrq-trigge=
r

Or lookin= g at /proc/buddyinfo

=C2=A0
=C2=A0
--
Thanks,
-aka
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