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From ba5bef1bb19b97c88b2e99071ffab067b7f3b9d3 Mon Sep 17 00:00:00 2001
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Message-Id: <ba5bef1bb19b97c88b2e99071ffab067b7f3b9d3.1389014116.git.minovotn@redhat.com>
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In-Reply-To: <c8cc35838d42aa286242772d97e3a9be7bb786ba.1389014116.git.minovotn@redhat.com>
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References: <c8cc35838d42aa286242772d97e3a9be7bb786ba.1389014116.git.minovotn@redhat.com>
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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Mon, 9 Dec 2013 14:09:36 +0100
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Subject: [PATCH 48/50] qemu-img: dynamically adjust iobuffer size during
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 convert
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RH-Author: Paolo Bonzini <pbonzini@redhat.com>
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Message-id: <1386598178-11845-51-git-send-email-pbonzini@redhat.com>
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Patchwork-id: 56087
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O-Subject: [RHEL 7.0 qemu-kvm PATCH 50/52] qemu-img: dynamically adjust iobuffer size during convert
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Bugzilla: 1039557
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RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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From: Peter Lieven <pl@kamp.de>
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since the convert process is basically a sync operation it might
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be benificial in some case to change the hardcoded I/O buffer
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size to a greater value.
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This patch increases the I/O buffer size if the output
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driver advertises an optimal transfer length or discard alignment
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that is greater than the default buffer size of 2M.
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Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
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Signed-off-by: Peter Lieven <pl@kamp.de>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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(cherry picked from commit f2521c9023067a007d18b844fe7639c1c5b6f2ac)
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---
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 qemu-img.c | 16 +++++++++++++---
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 1 file changed, 13 insertions(+), 3 deletions(-)
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Signed-off-by: Michal Novotny <minovotn@redhat.com>
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---
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 qemu-img.c | 16 +++++++++++++---
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 1 file changed, 13 insertions(+), 3 deletions(-)
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diff --git a/qemu-img.c b/qemu-img.c
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index c81d70a..6890bb1 100644
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--- a/qemu-img.c
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+++ b/qemu-img.c
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@@ -1133,6 +1133,7 @@ static int img_convert(int argc, char **argv)
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             sector_num_next_status = 0;
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     uint64_t bs_sectors;
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     uint8_t * buf = NULL;
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+    size_t bufsectors = IO_BUF_SIZE / BDRV_SECTOR_SIZE;
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     const uint8_t *buf1;
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     BlockDriverInfo bdi;
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     QEMUOptionParameter *param = NULL, *create_options = NULL;
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@@ -1369,7 +1370,16 @@ static int img_convert(int argc, char **argv)
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     bs_i = 0;
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     bs_offset = 0;
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     bdrv_get_geometry(bs[0], &bs_sectors);
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-    buf = qemu_blockalign(out_bs, IO_BUF_SIZE);
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+
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+    /* increase bufsectors from the default 4096 (2M) if opt_transfer_length
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+     * or discard_alignment of the out_bs is greater. Limit to 32768 (16MB)
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+     * as maximum. */
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+    bufsectors = MIN(32768,
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+                     MAX(bufsectors, MAX(out_bs->bl.opt_transfer_length,
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+                                         out_bs->bl.discard_alignment))
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+                    );
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+
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+    buf = qemu_blockalign(out_bs, bufsectors * BDRV_SECTOR_SIZE);
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     if (skip_create) {
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         int64_t output_length = bdrv_getlength(out_bs);
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@@ -1392,7 +1402,7 @@ static int img_convert(int argc, char **argv)
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             goto out;
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         }
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         cluster_size = bdi.cluster_size;
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-        if (cluster_size <= 0 || cluster_size > IO_BUF_SIZE) {
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+        if (cluster_size <= 0 || cluster_size > bufsectors * BDRV_SECTOR_SIZE) {
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             error_report("invalid cluster size");
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             ret = -1;
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             goto out;
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@@ -1529,7 +1539,7 @@ static int img_convert(int argc, char **argv)
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                 sector_num_next_status = sector_num + n1;
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             }
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-            n = MIN(nb_sectors, IO_BUF_SIZE / 512);
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+            n = MIN(nb_sectors, bufsectors);
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             n = MIN(n, bs_sectors - (sector_num - bs_offset));
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             n1 = n;
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-- 
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1.7.11.7
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