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Mon, 26 Oct 2026 09:41:16 +0000 (UTC) X-FDA: 85364284194.12.CAD7467 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf11.hostedemail.com (Postfix) with ESMTP id 3413040002 for ; Mon, 26 Oct 2026 09:41:15 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=hoY+nVJd; spf=pass (imf11.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793007675; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=fmErr11J4yiDe+oqOLxrAHXMe+lgqHj/gW1PNNiv0PY=; b=IHBCf42cjm8dKo7LDalms2s6wPr4bnibZ2tDiUs6q0eNmg7qYm10c8LoxGwf6r7Rg0Qfc4 nkGara+IDDXGhF2rQ+d4onY007asJoM+Yq0ekOMEYTwy6nUrohTB8MSvxATVW408vhEIyB +K26LgP6Cn3W0zLqCSOE6cmz6xz4+JQ= ARC-Seal: i=1; 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b=hoY+nVJdTpF+bOnGRqA60bqEon5wES0uTDgRThXCOwAPT/eYwNotrJ8PurgaBDBH8 6RTUTlsQSoBeGbuLzwDPLxO6Tg9aX0DzEGmjJzZhajmJdWtdQFKWaGv+iqM+2uBKpu 026t64oG7a4GhVyDaiFRtUzs+QhNWsy1qp4OK/oABUnwArhQHMz6REf23JPiDPpyUt H3PBDpVbqxeuL8lP8i6Dj/GHiIrypsBVaNKkQxsf+1b7KTZ/1TIdboA/vnbPXaRbcE n8p/qSrc52pFTkI67KgPo+ShAyE6zmyE2/FC0JJN0+EVo+8neJxNDYKWgRVYf+Oiv/ WBm0YdS18Y/Ng== Message-ID: Date: Sun, 25 Oct 2026 13:43:55 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: ppm: add PPM (Page-Plugger Under Memory) to Page Fault and Overcommit elimination To: dev12124 , linux-mm@kvack.org Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, ardb@kernel.org, keescook@chromium.org References: <20261024104552.394-1-joaoanandalima@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20261024104552.394-1-joaoanandalima@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 3413040002 X-Stat-Signature: g1urzyucnof1czw5nofh7itiju8os93r X-Rspam-User: X-Spam-Status: No, score=-16.5 required=3.0 tests=BAYES_00,DATE_IN_PAST_12_24, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1793007675-261950 X-HE-Meta: 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 R0hpzxKb U4tzg8MBwl4VeGunF+Mu0yam4FAQ0fqaVB2HgGuD+FftBooGCHO4SqQOtHW3cTuvcGnmb/+jvDIMIh7CvGMui9TjcIkK1xumAslAgA+HyI7M9mcwhMND9TIK7Uxlrz9QS6p0WKgGaSWhrEbiwvTN23XY43ygl0F126RZKKlmM/KHK52/lUbQrvRxJUyqp9eR0RHZuTwLKxKeEOauvI6LD5+wsAZH7tHVSLGa4eEWMF5D5S558QqRwmvZX+qlioUq2F3RiC1PQmnyfGwEZeOacNSpKPc4n9WRZjT6pRWvPXIXEOG7icOk22Tlo9g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 10/24/26 12:45, dev12124 wrote: > Hi mm subsystem, Hi, > > This patch implements the Memory Tatic called PPM, Page-Plugger Under Memory. > The Main Objective is: Page Faults and Overcommit Elimination. > > A few points under additionate: > > 1. Allocation Handshake (ppm_kalloc): > Using the GFP_PLUG_MEMORY mask, the allocator completely bypasses > passive overcommit verification. It instantly isolates physical frames > on the RAM, maps the page table entries síncronamente, and forces the > Present Bit and Writable Bit to 1 before returning the address block > register to the CPU. > > 2. Desallocation Cleanup (ppm_kfree): > Triggered via the GFP_FREE_T parameter, the release phase executes an > immediate length truncation to 0. It forces a synchronous TLB > invalidation (via invlpg execution) and flushes the data out of the L3 > cache lines using clflushopt instructions before moving the hot clean > pages into a dedicated priority recycling pool. > > I additionate a Buffer/Cache with store important objects. Reading this description I have no idea what this patch does, what it tries to solve, and why anybody should spend their time to look into it. > --- > include/linux/ppm/gfp_types.h | 74 ++++++++++++++++ > include/linux/slab.h | 11 +++ > mm/memory.c | 158 ++++++++++++++++++++++++++++++++++ > 3 files changed, 243 insertions(+) > create mode 100644 include/linux/ppm/gfp_types.h > > diff --git a/include/linux/ppm/gfp_types.h b/include/linux/ppm/gfp_types.h > new file mode 100644 > index 000000000..741122b2d > --- /dev/null > +++ b/include/linux/ppm/gfp_types.h > @@ -0,0 +1,74 @@ > +/* > + Memory Tatic: PPM (Page-Plugger Under Memory). > + This File is for PPM Flags/Macros/Functions/Types. > + Engineer (brazilian): João Guilherme da Silva Freitas Lima > + */ > + > +/* Types Include Guards */ > +#ifndef __PPM_TYPES_MEMORY > +#define __PPM_TYPES_MEMORY > + > +typedef unsigned char uint8_t; > +typedef unsigned short uint16_t; > +typedef unsigned int uint32_t; > +typedef unsigned long long uint64_t; > +typedef uint64_t gfp_t; > +/* For errors in Allocation */ > +#define __PPM_ALLOC_ERROR -102 > +/* For errors in Desallocation */ > +#define __PPM_FREE_ERROR 0x04 > +/* For success */ > +#define __PPM_SUCCESS 0 > +#endif > + > +/* Functions Include Guards */ > +#ifndef __PPM_FUNCTIONS_MEMORY > +#define __PPM_FUNCTIONS_MEMORY > + > +/* Initializer */ > +void __init_ppm_memory(); > + > +/* Allocator Optimized */ > +int ppm_kalloc(unsigned long address, uint64_t size, gfp_t flags); > + > +/* Desallocator Optimized */ > +int ppm_kfree(uint64_t size); > + > +#endif > + > +/* Flags Include Guards */ > +#ifndef __PPM_FLAGS_MEMORY > +#define __PPM_FLAGS_MEMORY > + > +/* PPM inits/starts in Bit 54 of a > + 64-bit variable > + */ > +gfp_t GFP_PLUG_MEMORY = (1ULL << 54); > + > +/* For free memory, the Bit 55 is > + used > + */ > +gfp_t GFP_FREE_T = (1ULL << 55); > + > +#endif > + > +/* Macros Include Guards */ > +#ifndef __PPM_MACROS_MEMORY > +#define __PPM_MACROS_MEMORY > + > +/* For Kernel Kernel tests 2 Bits (54 and 55) in > + 1 Clock Cycle (or in small clocks, example: 5 Clocks), > + is used a mask using | > + */ > +gfp_t GFP_MASK = GFP_PLUG_MEMORY | GFP_FREE_T; > + > +#endif > + > +/* > + Notes: > + E-Mail of RFC: > + [RFC] mm: page-fault: overcommit: PPM (Page-Plugger Under Memory) > + > + > + Assigned-Off-by: João I don't know if I am supposed to laugh or cry ;) -- Cheers, David