From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 12155A034E; Thu, 23 Apr 2020 18:33:47 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id EAF141C25A; Thu, 23 Apr 2020 18:33:46 +0200 (CEST) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by dpdk.org (Postfix) with ESMTP id D07F71C241 for ; Thu, 23 Apr 2020 18:33:44 +0200 (CEST) IronPort-SDR: YjRphFV6xVnzw6cdPoq5zFxHEQTO4rklj1XKMyPNK4IJhfNwWGEfi8Ef0PXUqjPjqWZkEuxrbp xuPt8l85k+MA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Apr 2020 09:33:44 -0700 IronPort-SDR: lXBwzULSENcXolzTJ5ssr4ixrCvILrA1ZvahOSSFwc7TLrWo622RNTD6eH2ETFl5bisXTwbFkP Ms0LXZGp7Qsg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,307,1583222400"; d="scan'208";a="280466100" Received: from aburakov-mobl.ger.corp.intel.com (HELO [10.213.241.89]) ([10.213.241.89]) by fmsmga004.fm.intel.com with ESMTP; 23 Apr 2020 09:33:42 -0700 To: Li Feng Cc: dev@dpdk.org, kyle@smartx.com, lifeng1519@gmail.com, fanyang@smartx.com References: <20200420070508.645533-1-fengli@smartx.com> <20200423154302.2217041-1-fengli@smartx.com> From: "Burakov, Anatoly" Message-ID: <9d6dc63b-34f7-36b3-5c3f-df74b71d961c@intel.com> Date: Thu, 23 Apr 2020 17:33:41 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200423154302.2217041-1-fengli@smartx.com> Content-Type: text/plain; charset=gbk; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v2] eal: add madvise to avoid dump memory X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 23-Apr-20 4:43 PM, Li Feng wrote: > Avoid dump all mapped memory to a core dump file when crash. > Otherwise it will very large and it's hard to analyze with gdb. > > In my test, it will dump 128GiB memory to a core dump file when integrated > to spdk with default configuration. Suggested rewording: Currently, even though memory is mapped with PROT_NONE, this does not cause it to be excluded from core dumps. This is counter-productive, because in a lot of cases, this memory will go unused (e.g. when the memory subsystem preallocates VA space but hasn't yet mapped physical pages into it). Use `madvise()` call with MADV_DONTDUMP parameter to exclude the unmapped memory from being dumped. > > Signed-off-by: Li Feng > --- > lib/librte_eal/common/eal_common_memory.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c > index cc7d54e0c..2d9564b28 100644 > --- a/lib/librte_eal/common/eal_common_memory.c > +++ b/lib/librte_eal/common/eal_common_memory.c > @@ -177,6 +177,20 @@ eal_get_virtual_area(void *requested_addr, size_t *size, > after_len = RTE_PTR_DIFF(map_end, aligned_end); > if (after_len > 0) > munmap(aligned_end, after_len); > + > + /* > + * Exclude this pages from a core dump. > + */ > + if (madvise(aligned_addr, *size, MADV_DONTDUMP) != 0) > + RTE_LOG(WARNING, EAL, "Madvise with MADV_DONTDUMP failed: %s\n", > + strerror(errno)); > + } else { > + /* > + * Exclude this pages from a core dump. > + */ > + if (madvise(mapped_addr, map_sz, MADV_DONTDUMP) != 0) > + RTE_LOG(WARNING, EAL, "Madvise with MADV_DONTDUMP failed: %s\n", > + strerror(errno)); > } > > return aligned_addr; > For the contents of this patch, Acked-by: Anatoly Burakov However, even though this is good to have, after some more thought, i believe the fix is incomplete, because this is not the only place we're reserving anonymous memory. We're also doing so in `eal_memalloc.c:free_seg()`, so an `madvise()` call should also be added there. @David, now that i think of it, the PROT_NONE patch also was incomplete, as we only set PROT_NONE to memory that's initially reserved, but not when it's unmapped and returned back to the pool of anonymous memory. So, eal_memalloc.c should also remap anonymous memory with PROT_NONE. @Li Feng, would you be so kind as to provide a patch replacing PROT_READ with PROT_NONE in eal_memalloc.c as well? Thank you very much! -- Thanks, Anatoly