80 lines
2.7 KiB
Diff
80 lines
2.7 KiB
Diff
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From f88c2f1b54da7a92420724189a6df37e6b3faed3 Mon Sep 17 00:00:00 2001
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From: Tim Smith <tim.smith@citrix.com>
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Date: Fri, 2 Nov 2018 10:01:09 +0000
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Subject: [PATCH] xen_disk: Avoid repeated memory allocation
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xen_disk currently allocates memory to hold the data for each ioreq
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as that ioreq is used, and frees it afterwards. Because it requires
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page-aligned blocks, this interacts poorly with non-page-aligned
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allocations and balloons the heap.
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Instead, allocate the maximum possible requirement, which is
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BLKIF_MAX_SEGMENTS_PER_REQUEST pages (currently 11 pages) when
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the ioreq is created, and keep that allocation until it is destroyed.
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Since the ioreqs themselves are re-used via a free list, this
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should actually improve memory usage.
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Signed-off-by: Tim Smith <tim.smith@citrix.com>
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[BSC#1100408]
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Signed-off-by: Bruce Rogers <brogers@suse.com>
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---
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hw/block/xen_disk.c | 7 ++-----
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1 file changed, 2 insertions(+), 5 deletions(-)
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diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
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index d9a55faf27..e9501ee34c 100644
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--- a/hw/block/xen_disk.c
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+++ b/hw/block/xen_disk.c
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@@ -110,7 +110,6 @@ static void ioreq_reset(struct ioreq *ioreq)
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memset(&ioreq->req, 0, sizeof(ioreq->req));
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ioreq->status = 0;
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ioreq->start = 0;
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- ioreq->buf = NULL;
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ioreq->size = 0;
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ioreq->presync = 0;
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@@ -135,6 +134,7 @@ static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
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/* allocate new struct */
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ioreq = g_malloc0(sizeof(*ioreq));
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ioreq->blkdev = blkdev;
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+ ioreq->buf = qemu_memalign(XC_PAGE_SIZE, BLKIF_MAX_SEGMENTS_PER_REQUEST * XC_PAGE_SIZE);
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blkdev->requests_total++;
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qemu_iovec_init(&ioreq->v, 1);
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} else {
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@@ -317,14 +317,12 @@ static void qemu_aio_complete(void *opaque, int ret)
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if (ret == 0) {
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ioreq_grant_copy(ioreq);
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}
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- qemu_vfree(ioreq->buf);
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break;
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case BLKIF_OP_WRITE:
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case BLKIF_OP_FLUSH_DISKCACHE:
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if (!ioreq->req.nr_segments) {
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break;
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}
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- qemu_vfree(ioreq->buf);
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break;
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default:
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break;
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@@ -392,12 +390,10 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
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{
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struct XenBlkDev *blkdev = ioreq->blkdev;
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- ioreq->buf = qemu_memalign(XC_PAGE_SIZE, ioreq->size);
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if (ioreq->req.nr_segments &&
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(ioreq->req.operation == BLKIF_OP_WRITE ||
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ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) &&
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ioreq_grant_copy(ioreq)) {
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- qemu_vfree(ioreq->buf);
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goto err;
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}
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@@ -1007,6 +1003,7 @@ static int blk_free(struct XenDevice *xendev)
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ioreq = QLIST_FIRST(&blkdev->freelist);
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QLIST_REMOVE(ioreq, list);
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qemu_iovec_destroy(&ioreq->v);
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+ qemu_vfree(ioreq->buf);
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g_free(ioreq);
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}
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