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Wed, 31 Jan 2024 13:19:42 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id VSurH+5IumX2BAAAD6G6ig (envelope-from ); Wed, 31 Jan 2024 13:19:42 +0000 From: Fabiano Rosas To: Peter Xu Cc: "Liu, Yuan1" , "qemu-devel@nongnu.org" , Hao Xiang , Bryan Zhang Subject: Re: [PATCH 0/5] migration/multifd: Prerequisite cleanups for ongoing work In-Reply-To: References: <20240126221943.26628-1-farosas@suse.de> <87jznse211.fsf@suse.de> Date: Wed, 31 Jan 2024 10:19:40 -0300 Message-ID: <8734udljwz.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=itQV7FST; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=uCToyYiv X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Spamd-Result: default: False [-6.51 / 50.00]; ARC_NA(0.00)[]; TO_DN_EQ_ADDR_SOME(0.00)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; BAYES_HAM(-3.00)[100.00%]; MIME_GOOD(-0.10)[text/plain]; NEURAL_HAM_LONG(-1.00)[-1.000]; DWL_DNSWL_MED(-2.00)[suse.de:dkim]; RCPT_COUNT_FIVE(0.00)[5]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DKIM_TRACE(0.00)[suse.de:+]; MX_GOOD(-0.01)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; NEURAL_HAM_SHORT(-0.20)[-0.999]; RCVD_TLS_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[] X-Rspamd-Queue-Id: 3E2832209B Received-SPF: pass client-ip=195.135.223.130; envelope-from=farosas@suse.de; helo=smtp-out1.suse.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Peter Xu writes: > On Mon, Jan 29, 2024 at 09:51:06AM -0300, Fabiano Rosas wrote: >> Peter Xu writes: >> >> > On Mon, Jan 29, 2024 at 01:41:01AM +0000, Liu, Yuan1 wrote: >> >> Because this change has an impact on the previous live migration >> >> With IAA Patch, does the submission of the next version needs >> >> to be submitted based on this change? >> > >> > I'd say hold off a little while until we're more certain on the planned >> > interface changes, to avoid you rebase your code back and forth; unless >> > you're pretty confident that this will be the right approach. >> > >> > I apologize on not having looked at any of the QAT/IAA compression / zero >> > detection series posted on the list; I do plan to read them very soon too >> > after Fabiano. So I may not have a complete full picture here yet, please >> > bare with me. >> > >> > If this series is trying to provide a base ground for all the efforts, >> > it'll be great if we can thoroughly discuss here and settle an approach >> > soon that will satisfy everyone. >> >> Just a summary if it helps: >> >> For compression work (IAA/QPL, QAT) the discussion is around having a >> new "compression acceleration" option that enables the accelerators and >> is complementary to the existing zlib compression method. We'd choose >> those automatically based on availability and we'd make HW accelerated >> compression produce a stream that is compatible with QEMU's zlib stream >> so we could migrate between solutions. >> >> For zero page work and zero page acceleration (DSA), the question is how >> to fit zero page detection into multifd and whether we need a new hook >> multifd_ops->zero_page_detect() (or similar) to allow client code to >> provide it's own zero page detection methods. My worry here is that >> teaching multifd to recognize zero pages is one more coupling to the >> "pages" data type. Ideallly we'd find a way to include that operation as >> a prepare() responsibility and the client code would deal with it. > > Thanks Fabiano. > > Since I'm preparing the old series to post for some fundamental cleanups > around multifd, and when I'm looking around the code, I noticed that > _maybe_ it'll also be eaiser to apply such a series if we can cleanup more > things then move towards a clean base to add more accelerators. > > I agree many ideas in your this series, but I may address it slightly > different (e.g., I want to avoid send(), but you can consider that in the > fixed-ram series instead), also it'll be after some other cleanup I plan to > give a stab at which is not yet covered in this series. I hope I can add > your "Co-developed-by" in some of the patches there. If you haven't spend > more time on new version of this series, please wait 1-2 days so I can post > my thoughts. Sure, go ahead.