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[46.208.116.5]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4601f2ec711sm7254825f8f.12.2026.06.03.06.06.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Jun 2026 06:06:19 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" Authentication-Results: eu.smtp.expurgate.cloud; dkim=pass header.s=20251104 header.d=gmail.com header.i="@gmail.com" header.h="Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1780491980; x=1781096780; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=NqFYUY4LLWBRQq7NSsaodrilUaXJC/aM45b33pOy+8Y=; b=IKWctpKYbAKP9veP3t90mlK5BPpK9SdK8WE36hycjpQXKR1dPpUoCn/W04RMznElso 24Sb7YkKyPrtByWMDPDnLHFGvX58pMLsTgU5qLFcbBuFVtTS2vKmM6YSuyzAqaR3IpYZ 29ddcPVjFKH52rLCbAPX+Wf+UZFi4zYSY/YA3MysAeP+A/b++baGXdvaWWkixMpf+AyP 1DOfNI4qpNQ/52FLFD5aoKffmrkgCEurUiCVy2ooOw4NnOyHNJVwuau1gz053Jkwgfm9 Y2XtQUTPyFbKApBeO3kz8w4M6/21wzUWmu5cHhEo80Iiatv3ia4XqqWhiVHfUeV8rcXt teXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780491980; x=1781096780; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=NqFYUY4LLWBRQq7NSsaodrilUaXJC/aM45b33pOy+8Y=; b=fan7yccUNFKeonjGulq6vBVp443Ei5iPIv4Bnq1OrAR0WVZUdbLutxmZJKizgSuM6/ BpR85QhzwsR4z76yVoYOhJw73OPnaxD6Rcunzc9XWNm0DJzZqE7Ypp2Dmwt74NOv6q3q PEpfEY14Y1QpLI5d2mHXHEJ6R4oEsla+LdI9KMSRNuwq98VAzT0QqG8LPiZ6sGIzUnzJ g/W5k9j0NZoJI7/IZqxXdeq7sbm4nAwQhYmKZ121FxRdXgqACT7mBKnEpeKPaBlAOuTn VmG5RkzHrIaDUGIUECHrwBj11kVlJh74Wnkrgv9B9xwZVXLnZhhS7Y6wtlPXnoNk1Fd6 5dtQ== X-Gm-Message-State: AOJu0YxkMX/dBGm2yt1b0/EX3yQWR0HYtvknxhhekHqrU6xB7twK2JRX pL9I5D0SHB0tW+cR6JuHZHuDWbKHoeBa1cu5Pvx7LrnqxO6mguJRBnbtWtShi69v X-Gm-Gg: Acq92OGrBd4Op4FipnqWCxmWsSnDf9Mr6EDyS/wvoOgXAAGlAVGTk7aydiMyHKFkV8C 3Y0a+q6r26Rk9eJtCht9CzgRDH5D8Kczu/MY9rAcUcTo9xQDvPasq1IxKnMuxIguQAVCcoDR98M xBrjeYPfjh9hJ7Q8agjbqkxY/Zho7SSLQ9hmAKLH2Et70GIwb3J5mdPdt2pBapXIa5/R/qYUXYS 4USawKWqlnD7DURKJQcXtjPsJAQD8wyHXZLsj2cVaUTW+apBTWJj1X6L10836Wl62jQg/d+nKub 7aVCV+29aDS4PC7BGYaf3m3To41W5nsAqPiAseTHm8RSSilETutb6QR7CEBNotyiafzP+Y+9nZ/ KJE3IATxKzZpgdIAqZFSRNizjQSORhLn9JC7vLnMG0G9cqqB2S7rZPI7NEtwcjFw3txFQIPh9kE CIfUrLL7h3z2tSBDF4wGi1KqZhsHXQx2yPvvAI97S60Ll4oFWercjvZgfees0w5c8QbQnVZ+vzh gEhCPOsi4S31sXKtABtI9MWnGCz7RkexZnmTJlGF7gnpwI= X-Received: by 2002:a5d:4a02:0:b0:44a:2cb3:b633 with SMTP id ffacd0b85a97d-46021794f73mr3643466f8f.12.1780491979837; Wed, 03 Jun 2026 06:06:19 -0700 (PDT) From: Frediano Ziglio X-Google-Original-From: Frediano Ziglio To: xen-devel@lists.xenproject.org Cc: Frediano Ziglio , Jan Beulich , Andrew Cooper , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Teddy Astie , Anthony PERARD , Juergen Gross Subject: [PATCH v4 03/16] libs/guest: Reduce number of I/O vectors in write_batch Date: Wed, 3 Jun 2026 14:05:50 +0100 Message-ID: <20260603130603.776452-4-frediano.ziglio@cloud.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260603130603.776452-1-frediano.ziglio@cloud.com> References: <20260603130603.776452-1-frediano.ziglio@cloud.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-purgate-ID: tlsNG-ebf023/1780491980-2B1663FF-29F4062E/0/0 X-purgate-type: clean X-purgate-size: 1324 From: Frediano Ziglio Each page was sent using a different iovec item. This potentially exceed Linux maximum (1024). Also some implementation (MiniOS) emulate writev with multiple write calls. Signed-off-by: Frediano Ziglio -- Changes since v2: - change prefix in subject. --- tools/libs/guest/xg_sr_save.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/tools/libs/guest/xg_sr_save.c b/tools/libs/guest/xg_sr_save.c index 1700d81905..62a39dfecc 100644 --- a/tools/libs/guest/xg_sr_save.c +++ b/tools/libs/guest/xg_sr_save.c @@ -240,13 +240,20 @@ static int write_batch(struct xc_sr_context *ctx) { for ( i = 0; i < nr_pfns; ++i ) { - if ( guest_data[i] ) + if ( !guest_data[i] ) + continue; + + if ( iov[iovcnt-1].iov_base + iov[iovcnt-1].iov_len != guest_data[i] ) { iov[iovcnt].iov_base = guest_data[i]; iov[iovcnt].iov_len = PAGE_SIZE; iovcnt++; - --nr_pages; } + else + { + iov[iovcnt-1].iov_len += PAGE_SIZE; + } + --nr_pages; } } -- 2.54.0