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Shutemov" , Joerg Roedel , Uros Bizjak , Alistair Popple , linux-arch Subject: Re: mm: delay rmap removal until after TLB flush Message-ID: References: <140B437E-B994-45B7-8DAC-E9B66885BEEF@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 4FNpXyGGRtv1khih7wgAOdB8NGiyES6G X-Proofpoint-ORIG-GUID: oUVm0NIeVEvSk1VZrf3NeD5Pcsl8qKsp X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-11-04_02,2022-11-03_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 spamscore=0 impostorscore=0 adultscore=0 bulkscore=0 mlxlogscore=921 mlxscore=0 priorityscore=1501 clxscore=1011 malwarescore=0 phishscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2210170000 definitions=main-2211040044 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1667543615; a=rsa-sha256; cv=none; b=xCbEBNTyC3V6OunWT71cDn9LP/zF0WfgC/dVAgnCVMggJe0lR8tMpwla8MzjwVlg2us9+5 GJiAJ6miphfu+0q/CRYYywdiXTZ/e9tC+hdD7Zxow3+g69ymEiOq0FuhCKesylYD9Fe4Wr oEnCIjg/PqUmN6WcM5cBQo11xjWqjyw= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=sh3WaLpz; spf=pass (imf27.hostedemail.com: domain of agordeev@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=agordeev@linux.ibm.com; dmarc=pass (policy=none) header.from=ibm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1667543615; 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=DVozv4ww3RPgAifx8iLDCASk/cNq9WwNyTxXIFAOdb0=; b=mOA4EpJ7fCIe1A3X1gJIzq5NlG0Fb5wyXp5beYG6uNjHhIKLeaTG8zLSVK5gxsJowuttAG IsJeRchQffpU9zVSNIK2t9PMqZx6KZI+vAH3lsuVY8SPyl6ojz3mUWQmCIm9LSzF7dmPTX NlsxRJGJKFIAZ1AkJysBmxn+P0DvBhg= X-Stat-Signature: p5mtx5befahnqu66pnm63qb6pfgqsgkf X-Rspamd-Server: rspam09 X-Rspam-User: X-Rspamd-Queue-Id: 668E740004 Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=sh3WaLpz; spf=pass (imf27.hostedemail.com: domain of agordeev@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=agordeev@linux.ibm.com; dmarc=pass (policy=none) header.from=ibm.com X-HE-Tag: 1667543615-546014 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 Mon, Oct 31, 2022 at 11:43:30AM -0700, Linus Torvalds wrote: [...] > If people really want to see the patches in email again, I can do > that, but most of you already have, and the changes are either trivial > fixes or the s390 updates. > > For the s390 people that I've now added to the participant list maybe > the git tree is fine - and the fundamental explanation of the problem > is in that top-most commit (with the three preceding commits being > prep-work). Or that link to the thread about this all. I rather have a question to the generic part (had to master the code quotting). > static void clean_and_free_pages_and_swap_cache(struct encoded_page **pages, unsigned int nr) > { > for (unsigned int i = 0; i < nr; i++) { > struct encoded_page *encoded = pages[i]; > unsigned int flags = encoded_page_flags(encoded); > if (flags) { > /* Clean the flagged pointer in-place */ > struct page *page = encoded_page_ptr(encoded); > pages[i] = encode_page(page, 0); > > /* The flag bit being set means that we should zap the rmap */ Why TLB_ZAP_RMAP bit is not checked explicitly here, like in s390 version? (I assume, when/if ENCODE_PAGE_BITS is not TLB_ZAP_RMAP only, calling page_zap_pte_rmap() without such a check would be a bug). > page_zap_pte_rmap(page); > VM_WARN_ON_ONCE_PAGE(page_mapcount(page) < 0, page); > } > } > > /* > * Now all entries have been un-encoded, and changed to plain > * page pointers, so we can cast the 'encoded_page' array to > * a plain page array and free them > */ > free_pages_and_swap_cache((struct page **)pages, nr); > } Thanks!