Commit e6129b27 authored by David Hildenbrand's avatar David Hildenbrand Committed by Michael S. Tsirkin
Browse files

virtio-balloon: Better names for offset variables in inflate/deflate code 



"host_page_base" is really confusing, let's make this clearer, also
rename the other offsets to indicate to which base they apply.

offset -> mr_offset
ram_offset -> rb_offset
host_page_base -> rb_aligned_offset

While at it, use QEMU_ALIGN_DOWN() instead of a handcrafted computation
and move the computation to the place where it is needed.

Acked-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Message-Id: <20190722134108.22151-5-david@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 2ffc49ee

hw/virtio/virtio-balloon.c

+13 −13
Original line number Diff line number Diff line
@@ -41,24 +41,23 @@ struct PartiallyBalloonedPage { 
};



static void balloon_inflate_page(VirtIOBalloon *balloon,

                                 MemoryRegion *mr, hwaddr offset)

                                 MemoryRegion *mr, hwaddr mr_offset)

{

    void *addr = memory_region_get_ram_ptr(mr) + offset;

    void *addr = memory_region_get_ram_ptr(mr) + mr_offset;

    ram_addr_t rb_offset, rb_aligned_offset;

    RAMBlock *rb;

    size_t rb_page_size;

    int subpages;

    ram_addr_t ram_offset, host_page_base;



    /* XXX is there a better way to get to the RAMBlock than via a

     * host address? */

    rb = qemu_ram_block_from_host(addr, false, &ram_offset);

    rb = qemu_ram_block_from_host(addr, false, &rb_offset);

    rb_page_size = qemu_ram_pagesize(rb);

    host_page_base = ram_offset & ~(rb_page_size - 1);



    if (rb_page_size == BALLOON_PAGE_SIZE) {

        /* Easy case */



        ram_block_discard_range(rb, ram_offset, rb_page_size);

        ram_block_discard_range(rb, rb_offset, rb_page_size);

        /* We ignore errors from ram_block_discard_range(), because it

         * has already reported them, and failing to discard a balloon

         * page is not fatal */
@@ -74,11 +73,12 @@ static void balloon_inflate_page(VirtIOBalloon *balloon, 
    warn_report_once(

"Balloon used with backing page size > 4kiB, this may not be reliable");



    rb_aligned_offset = QEMU_ALIGN_DOWN(rb_offset, rb_page_size);

    subpages = rb_page_size / BALLOON_PAGE_SIZE;



    if (balloon->pbp

        && (rb != balloon->pbp->rb

            || host_page_base != balloon->pbp->base)) {

            || rb_aligned_offset != balloon->pbp->base)) {

        /* We've partially ballooned part of a host page, but now

         * we're trying to balloon part of a different one.  Too hard,

         * give up on the old partial page */
@@ -91,10 +91,10 @@ static void balloon_inflate_page(VirtIOBalloon *balloon, 
        size_t bitlen = BITS_TO_LONGS(subpages) * sizeof(unsigned long);

        balloon->pbp = g_malloc0(sizeof(PartiallyBalloonedPage) + bitlen);

        balloon->pbp->rb = rb;

        balloon->pbp->base = host_page_base;

        balloon->pbp->base = rb_aligned_offset;

    }



    set_bit((ram_offset - balloon->pbp->base) / BALLOON_PAGE_SIZE,

    set_bit((rb_offset - balloon->pbp->base) / BALLOON_PAGE_SIZE,

            balloon->pbp->bitmap);



    if (bitmap_full(balloon->pbp->bitmap, subpages)) {
@@ -112,18 +112,18 @@ static void balloon_inflate_page(VirtIOBalloon *balloon, 
}



static void balloon_deflate_page(VirtIOBalloon *balloon,

                                 MemoryRegion *mr, hwaddr offset)

                                 MemoryRegion *mr, hwaddr mr_offset)

{

    void *addr = memory_region_get_ram_ptr(mr) + offset;

    void *addr = memory_region_get_ram_ptr(mr) + mr_offset;

    ram_addr_t rb_offset;

    RAMBlock *rb;

    size_t rb_page_size;

    ram_addr_t ram_offset;

    void *host_addr;

    int ret;



    /* XXX is there a better way to get to the RAMBlock than via a

     * host address? */

    rb = qemu_ram_block_from_host(addr, false, &ram_offset);

    rb = qemu_ram_block_from_host(addr, false, &rb_offset);

    rb_page_size = qemu_ram_pagesize(rb);



    if (balloon->pbp) {