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Shutemov" To: Peter Zijlstra Cc: Dave Hansen , Andy Lutomirski , x86@kernel.org, Kostya Serebryany , Andrey Ryabinin , Andrey Konovalov , Alexander Potapenko , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, namit@vmware.com Subject: Re: [PATCHv3 4/8] x86/mm: Handle LAM on context switch Message-ID: <20220616164012.uuok46yozncbwe7u@black.fi.intel.com> References: <20220610143527.22974-1-kirill.shutemov@linux.intel.com> <20220610143527.22974-5-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655397613; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=mg6g5P2Y2IXfThsBciAeyZib3IsuwJ8I8KG7rbkTK1Q=; b=rHDhd1SIlzYDYYmHdLGZt+WkwQ5t5k6cTuZD9hot0UezpzwxI9IT83hMqglMxQcBeJhzP9 OrSyCUm89j5iZDuNCmJV9ZjNWkThmwqKCBBw6VbaczJ2BFEHEMTaKMjVhyutOYUI+sYzd9 fNOuMNOCqw07/A5xgVCslMyYhGmt1q8= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655397613; a=rsa-sha256; cv=none; b=W8eDQ3sFnv6PTWez0mEIvucdXv3BsQ33MG2OZGnyz2Vb20nlpm0MZB6x787vaUaktXWrs8 TAiGBd+oc6d7l7/B8QGYtAF6x7tmbkrzufnJfA5qXZiEEKLDrncUn1szUEMm++SM7TTfjb HRMcRvIr6hTwu0X58Ek/7cZ9YfooQE8= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Hl1EAOEA; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf18.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.126) smtp.mailfrom=kirill.shutemov@linux.intel.com Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Hl1EAOEA; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf18.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.126) smtp.mailfrom=kirill.shutemov@linux.intel.com X-Rspamd-Server: rspam12 X-Rspam-User: X-Stat-Signature: hf1z3kmnrfryz1x6r9193dbj5hi7nsad X-Rspamd-Queue-Id: 21CAF1C0086 X-HE-Tag: 1655397612-168719 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 Thu, Jun 16, 2022 at 11:08:07AM +0200, Peter Zijlstra wrote: > Either use that one spare byte, or find room elsewhere I suppose. Okay, I will put into the byte after invalidate_other and modify tlbstate_lam_cr3_mask() and set_tlbstate_lam_cr3_mask() to shift it accordingly. It looks like this: struct tlb_state { struct mm_struct * loaded_mm; /* 0 8 */ union { struct mm_struct * last_user_mm; /* 8 8 */ unsigned long last_user_mm_spec; /* 8 8 */ }; /* 8 8 */ union { struct mm_struct * last_user_mm; /* 0 8 */ unsigned long last_user_mm_spec; /* 0 8 */ }; u16 loaded_mm_asid; /* 16 2 */ u16 next_asid; /* 18 2 */ bool invalidate_other; /* 20 1 */ u8 lam; /* 21 1 */ unsigned short user_pcid_flush_mask; /* 22 2 */ unsigned long cr4; /* 24 8 */ struct tlb_context ctxs[6]; /* 32 96 */ /* size: 128, cachelines: 2, members: 9 */ }; -- Kirill A. Shutemov