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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4ED7CC433F5 for ; Mon, 11 Oct 2021 06:50:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D82B760E90 for ; Mon, 11 Oct 2021 06:50:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D82B760E90 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 7DE706B006C; Mon, 11 Oct 2021 02:50:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 78D556B0071; Mon, 11 Oct 2021 02:50:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 655A9900002; 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Mon, 11 Oct 2021 06:50:04 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 814E7C43460; Mon, 11 Oct 2021 06:50:03 +0000 (UTC) Received: from [192.168.0.109] (unknown [49.204.182.166]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: faiyazm) by smtp.codeaurora.org (Postfix) with ESMTPSA id 70D17C4338F; Mon, 11 Oct 2021 06:50:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 smtp.codeaurora.org 70D17C4338F Subject: Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory To: David Hildenbrand , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: guptap@codeaurora.org References: <1632819849-511-1-git-send-email-faiyazm@codeaurora.org> <248ec931-7c16-3e2d-cc8f-8ce0dd4e923b@redhat.com> <0149edd5-fe7f-2786-413c-6de2eab3e30c@codeaurora.org> <1f6708d2-1ca8-6d1f-d9f0-855f2df755ed@codeaurora.org> <88df48af-901b-5765-d92c-6d14c2b1f73e@codeaurora.org> From: Faiyaz Mohammed Message-ID: Date: Mon, 11 Oct 2021 12:19:58 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 93559F002344 X-Stat-Signature: uh95uoeu3jkhqtkrac1n1fx6r8y1ikwg Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=mg.codeaurora.org header.s=smtp header.b=wy+VL4e0; dmarc=none; spf=pass (imf16.hostedemail.com: domain of "bounce+d06763.be9e4a-linux-mm=kvack.org@mg.codeaurora.org" designates 198.61.254.9 as permitted sender) smtp.mailfrom="bounce+d06763.be9e4a-linux-mm=kvack.org@mg.codeaurora.org" X-HE-Tag: 1633935012-472524 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 10/6/2021 5:48 PM, David Hildenbrand wrote: > On 06.10.21 14:13, Faiyaz Mohammed wrote: >> Hi, >> >> Sorry for delayed response. >> >> On 9/29/2021 10:33 PM, David Hildenbrand wrote: >>> On 29.09.21 10:58, Faiyaz Mohammed wrote: >>>> >>>> >>>> On 9/28/2021 4:46 PM, David Hildenbrand wrote: >>>>> On 28.09.21 12:53, Faiyaz Mohammed wrote: >>>>>> >>>>>> >>>>>> On 9/28/2021 4:09 PM, David Hildenbrand wrote: >>>>>>> On 28.09.21 11:04, Faiyaz Mohammed wrote: >>>>>>>> For INITRD and initmem memory is reserved through >>>>>>>> "memblock_reserve" >>>>>>>> during boot up but it is free via "free_reserved_area" instead >>>>>>>> of "memblock_free". >>>>>>>> For example: >>>>>>>> [=C2=A0=C2=A0=C2=A0 0.294848] Freeing initrd memory: 12K. >>>>>>>> [=C2=A0=C2=A0=C2=A0 0.696688] Freeing unused kernel memory: 4096= K. >>>>>>>> >>>>>>>> To get the start and end address of the above freed memory and t= o >>>>>>>> account >>>>>>>> proper memblock added memblock_dbg log in "free_reserved_area". >>>>>>>> After adding log: >>>>>>>> [=C2=A0=C2=A0=C2=A0 0.294837] memblock_free: [0x00000083600000-0= x00000083603000] >>>>>>>> free_initrd_mem+0x20/0x28 >>>>>>>> [=C2=A0=C2=A0=C2=A0 0.294848] Freeing initrd memory: 12K. >>>>>>>> [=C2=A0=C2=A0=C2=A0 0.695246] memblock_free: [0x00000081600000-0= x00000081a00000] >>>>>>>> free_initmem+0x70/0xc8 >>>>>>>> [=C2=A0=C2=A0=C2=A0 0.696688] Freeing unused kernel memory: 4096= K. >>>>>>>> >>>>>>>> Signed-off-by: Faiyaz Mohammed >>>>>>>> --- >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0 mm/page_alloc.c | 5 +++++ >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0 1 file changed, 5 insertions(+) >>>>>>>> >>>>>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >>>>>>>> index b37435c..f85c3b2 100644 >>>>>>>> --- a/mm/page_alloc.c >>>>>>>> +++ b/mm/page_alloc.c >>>>>>>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void >>>>>>>> *start, >>>>>>>> void *end, int poison, const char >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0 pr_info("Freeing %s memory: %ldK\n", >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 s, pages << (PAGE_SHIFT - 10)); >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0 +#ifdef CONFIG_HAVE_MEMBLOCK >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 memblock_dbg("memblo= ck_free: [%#016llx-%#016llx] %pS\n", >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0 __pa(start), __pa(end), (void *)_RET_IP_); >>>>>>>> +#endif >>>>>>> >>>>>>> IMHO, the "memblock_free" part is misleading. Something was >>>>>>> allocated >>>>>>> early via memblock, then we transitioned to the buddy, now we're >>>>>>> freeing >>>>>>> that early allocation via the buddy. >>>>>>> Yes, we're freeing the early allocation via buddy, but for proper >>>>>> memblock accounting we need this debug print. >>>>>> >>>>> >>>>> What do you mean with "accounting" ? These are debug statements. >>>>> >>>>> >>>> Yes, these are debug statements, which help to know the a-b address >>>> belongs to x callsite. This info is required when memblock=3Ddebug i= s >>>> passed through command line and CONFIG_HAVE_MEMBLOCK is enabled. >>> >>> The issue I'm having is talking in the name of memblock "memblock_dbg= , >>> memblock_free", when memblock might no longer be around. We have othe= r >>> places where we free early memblock allocations back to the buddy. >> I didn't find place where we free early memblock allocation back to th= e >> buddy. >=20 > One example I know is >=20 > section_deactivate()->free_map_bootmem()->vmemmap_free()-> ... > free_pagetable()->free_reserved_page(). >=20 > when we free the vmemmap allocated via memblock back to the buddy. >=20 >> >> Why "memblock_dbg" print with "memblock_free" string?. >> - After buddy took over, buddy will free memblock reserved memory >> through free_reserved_area and it will print the freed memory size, bu= t >> the freed memory through buddy still be part of >> memblock.reserved.regions. >> - To know the address ranges, added the "memblock_dbg" print along wit= h >> "membloc_free" string. >> - If it is misleading or confusing, we can remove the "memblock_free" >> string from the "memblock_dgb" print and we can just print the address >> range when "memlock=3Ddebug" pass through command line. >=20 > That would be better, but do we really have to depend on > "memlock=3Ddebug"? Can't we do pr_debug() ? >=20 Yes, I think we can do pr_debug. I will update the patch and push again. Thanks and regards, Mohammed Faiyaz