search for: get_unused_pages

...req_id) +{ + struct scatterlist sg_in; + unsigned long pos = 0; + struct virtqueue *vq = vb->req_vq; + struct virtio_balloon_resp_hdr *hdr = vb->resp_hdr; + int ret, order; + + mutex_lock(&vb->balloon_lock); + + for (order = MAX_ORDER - 1; order >= 0; order--) { + pos = 0; + ret = get_unused_pages(vb->resp_data, + vb->resp_buf_size / sizeof(unsigned long), + order, &pos); + if (ret == -ENOSPC) { + void *new_resp_data; + + new_resp_data = kmalloc(2 * vb->resp_buf_size, + GFP_KERNEL); + if (new_resp_data) { + kfree(vb->resp_data); + vb->resp_data = ne...

> On 10/20/2016 11:24 PM, Liang Li wrote: > > Dave Hansen suggested a new scheme to encode the data structure, > > because of additional complexity, it's not implemented in v3. > > So, what do you want done with this patch set? Do you want it applied as-is > so that we can introduce a new host/guest ABI that we must support until > the end of time? Then, we go

> On 10/20/2016 11:24 PM, Liang Li wrote: > > Dave Hansen suggested a new scheme to encode the data structure, > > because of additional complexity, it's not implemented in v3. > > So, what do you want done with this patch set? Do you want it applied as-is > so that we can introduce a new host/guest ABI that we must support until > the end of time? Then, we go

On 12/04/2016 05:13 AM, Li, Liang Z wrote: >> On 11/30/2016 12:43 AM, Liang Li wrote: >>> +static void send_unused_pages_info(struct virtio_balloon *vb, >>> + unsigned long req_id) >>> +{ >>> + struct scatterlist sg_in; >>> + unsigned long pos = 0; >>> + struct virtqueue *vq = vb->req_vq; >>> + struct

On 12/04/2016 05:13 AM, Li, Liang Z wrote: >> On 11/30/2016 12:43 AM, Liang Li wrote: >>> +static void send_unused_pages_info(struct virtio_balloon *vb, >>> + unsigned long req_id) >>> +{ >>> + struct scatterlist sg_in; >>> + unsigned long pos = 0; >>> + struct virtqueue *vq = vb->req_vq; >>> + struct

..._BITMAP) && > + vb->nr_page_bmap == 1) > + extend_page_bitmap(vb); > + > + pfn_limit = PFNS_PER_BMAP * vb->nr_page_bmap; > + mutex_lock(&vb->balloon_lock); > + last_pfn = get_max_pfn(); > + > + while (ret) { > + clear_page_bitmap(vb); > + ret = get_unused_pages(pfn, pfn + pfn_limit, vb->page_bitmap, > + PFNS_PER_BMAP, vb->nr_page_bmap); This changed the underlying data structure without changing the way that the structure is populated. This algorithm picks a "PFNS_PER_BMAP * vb->nr_page_bmap"-sized set of pfns, allocates a bitma...

..._BITMAP) && > + vb->nr_page_bmap == 1) > + extend_page_bitmap(vb); > + > + pfn_limit = PFNS_PER_BMAP * vb->nr_page_bmap; > + mutex_lock(&vb->balloon_lock); > + last_pfn = get_max_pfn(); > + > + while (ret) { > + clear_page_bitmap(vb); > + ret = get_unused_pages(pfn, pfn + pfn_limit, vb->page_bitmap, > + PFNS_PER_BMAP, vb->nr_page_bmap); This changed the underlying data structure without changing the way that the structure is populated. This algorithm picks a "PFNS_PER_BMAP * vb->nr_page_bmap"-sized set of pfns, allocates a bitma...

...tched my head for a bit on this one. Why are you walking over orders, *then* zones. I *think* you're doing it because you can efficiently fill the bitmaps at a given order for all zones, then move to a new bitmap. But, it would be interesting to document this. > + pos = 0; > + ret = get_unused_pages(vb->resp_data, > + vb->resp_buf_size / sizeof(unsigned long), > + order, &pos); FWIW, get_unsued_pages() is a pretty bad name. "get" usually implies bumping reference counts or consuming something. You're just "recording" or "marking" them....

...tched my head for a bit on this one. Why are you walking over orders, *then* zones. I *think* you're doing it because you can efficiently fill the bitmaps at a given order for all zones, then move to a new bitmap. But, it would be interesting to document this. > + pos = 0; > + ret = get_unused_pages(vb->resp_data, > + vb->resp_buf_size / sizeof(unsigned long), > + order, &pos); FWIW, get_unsued_pages() is a pretty bad name. "get" usually implies bumping reference counts or consuming something. You're just "recording" or "marking" them....

This patch set contains two parts of changes to the virtio-balloon. One is the change for speeding up the inflating & deflating process, the main idea of this optimization is to use bitmap to send the page information to host instead of the PFNs, to reduce the overhead of virtio data transmission, address translation and madvise(). This can help to improve the performance by about 85%.

This patch set contains two parts of changes to the virtio-balloon. One is the change for speeding up the inflating & deflating process, the main idea of this optimization is to use bitmap to send the page information to host instead of the PFNs, to reduce the overhead of virtio data transmission, address translation and madvise(). This can help to improve the performance by about 85%.

This patch set contains two parts of changes to the virtio-balloon. One is the change for speeding up the inflating & deflating process, the main idea of this optimization is to use bitmap to send the page information to host instead of the PFNs, to reduce the overhead of virtio data transmission, address translation and madvise(). This can help to improve the performance by about 85%.

This patch set contains two parts of changes to the virtio-balloon. One is the change for speeding up the inflating & deflating process, the main idea of this optimization is to use bitmap to send the page information to host instead of the PFNs, to reduce the overhead of virtio data transmission, address translation and madvise(). This can help to improve the performance by about 85%.

...ings will be much more > simple. Yes, using pfn lists is more efficient than using bitmaps for sparse bitmaps. Yes, there will be cases where it is preferable to just use pfn lists vs. any kind of bitmap. But, what does it matter? At least with your current scheme where we go out and collect get_unused_pages(), we do the allocation up front. The space efficiency doesn't matter at all for small sizes since we do the constant-size allocation *anyway*. I'm also pretty sure you can pack the pfn and page order into a single 64-bit word and have no bitmap for a given record. That would make it pac...

...l the > bitmaps at a given order for all zones, then move to a new bitmap. But, it > would be interesting to document this. > Yes, use the order is somewhat strange, but it's helpful to keep the API simple. Do you think it's acceptable? > > + pos = 0; > > + ret = get_unused_pages(vb->resp_data, > > + vb->resp_buf_size / sizeof(unsigned long), > > + order, &pos); > > FWIW, get_unsued_pages() is a pretty bad name. "get" usually implies > bumping reference counts or consuming something. You're just "recording" &gt...

...ap == 1) > > + extend_page_bitmap(vb); > > + > > + pfn_limit = PFNS_PER_BMAP * vb->nr_page_bmap; > > + mutex_lock(&vb->balloon_lock); > > + last_pfn = get_max_pfn(); > > + > > + while (ret) { > > + clear_page_bitmap(vb); > > + ret = get_unused_pages(pfn, pfn + pfn_limit, vb- > >page_bitmap, > > + PFNS_PER_BMAP, vb->nr_page_bmap); > > This changed the underlying data structure without changing the way that > the structure is populated. > > This algorithm picks a "PFNS_PER_BMAP * vb->nr_page_bmap"-...

This patch set contains two parts of changes to the virtio-balloon. One is the change for speeding up the inflating & deflating process, the main idea of this optimization is to use bitmap to send the page information to host instead of the PFNs, to reduce the overhead of virtio data transmission, address translation and madvise(). This can help to improve the performance by about 85%.

This patch set contains two parts of changes to the virtio-balloon. One is the change for speeding up the inflating & deflating process, the main idea of this optimization is to use bitmap to send the page information to host instead of the PFNs, to reduce the overhead of virtio data transmission, address translation and madvise(). This can help to improve the performance by about 85%.

...tio_has_feature(vb->vdev, VIRTIO_BALLOON_F_PAGE_BITMAP) && + vb->nr_page_bmap == 1) + extend_page_bitmap(vb); + + pfn_limit = PFNS_PER_BMAP * vb->nr_page_bmap; + mutex_lock(&vb->balloon_lock); + last_pfn = get_max_pfn(); + + while (ret) { + clear_page_bitmap(vb); + ret = get_unused_pages(pfn, pfn + pfn_limit, vb->page_bitmap, + PFNS_PER_BMAP, vb->nr_page_bmap); + if (ret < 0) + break; + hdr->cmd = BALLOON_GET_UNUSED_PAGES; + hdr->id = req_id; + bmap_len = BALLOON_BMAP_SIZE * vb->nr_page_bmap; + + if (!ret) { + hdr->flag = BALLOON_FLAG_DONE; + nr_p...

This patch set contains two parts of changes to the virtio-balloon. One is the change for speeding up the inflating & deflating process, the main idea of this optimization is to use bitmap to send the page information to host instead of the PFNs, to reduce the overhead of virtio data transmission, address translation and madvise(). This can help to improve the performance by about 85%.