| Message ID | 20210604205939.376598-1-vivek.kasireddy@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | udmabuf: Add support for mapping hugepages (v3) | expand |
I see the number of entries in the list often exceeds list_limit currently hardcoded to 1024 for full HD scanout resource (== 1920*1080*4 bytes). Can we include a change to increase it to something like 4096 or higher in this patch? On Fri, Jun 04, 2021 at 01:59:39PM -0700, Vivek Kasireddy wrote: > If the VMM's (Qemu) memory backend is backed up by memfd + Hugepages > (hugetlbfs and not THP), we have to first find the hugepage(s) where > the Guest allocations are located and then extract the regular 4k > sized subpages from them. > > v2: Ensure that the subpage and hugepage offsets are calculated correctly > when the range of subpage allocations cuts across multiple hugepages. > > v3: Instead of repeatedly looking up the hugepage for each subpage, > only do it when the subpage allocation crosses over into a different > hugepage. (suggested by Gerd and DW) > > Cc: Gerd Hoffmann <kraxel@redhat.com> > Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com> > Signed-off-by: Dongwon Kim <dongwon.kim@intel.com> > --- > drivers/dma-buf/udmabuf.c | 51 +++++++++++++++++++++++++++++++++------ > 1 file changed, 44 insertions(+), 7 deletions(-) > > diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c > index db732f71e59a..2e02bbfe30fd 100644 > --- a/drivers/dma-buf/udmabuf.c > +++ b/drivers/dma-buf/udmabuf.c > @@ -11,6 +11,7 @@ > #include <linux/shmem_fs.h> > #include <linux/slab.h> > #include <linux/udmabuf.h> > +#include <linux/hugetlb.h> > > static const u32 list_limit = 1024; /* udmabuf_create_list->count limit */ > static const size_t size_limit_mb = 64; /* total dmabuf size, in megabytes */ > @@ -163,7 +164,9 @@ static long udmabuf_create(struct miscdevice *device, > struct udmabuf *ubuf; > struct dma_buf *buf; > pgoff_t pgoff, pgcnt, pgidx, pgbuf = 0, pglimit; > - struct page *page; > + struct page *page, *hpage = NULL; > + pgoff_t subpgoff, maxsubpgs; > + struct hstate *hpstate; > int seals, ret = -EINVAL; > u32 i, flags; > > @@ -194,7 +197,8 @@ static long udmabuf_create(struct miscdevice *device, > memfd = fget(list[i].memfd); > if (!memfd) > goto err; > - if (!shmem_mapping(file_inode(memfd)->i_mapping)) > + if (!shmem_mapping(file_inode(memfd)->i_mapping) && > + !is_file_hugepages(memfd)) > goto err; > seals = memfd_fcntl(memfd, F_GET_SEALS, 0); > if (seals == -EINVAL) > @@ -205,17 +209,50 @@ static long udmabuf_create(struct miscdevice *device, > goto err; > pgoff = list[i].offset >> PAGE_SHIFT; > pgcnt = list[i].size >> PAGE_SHIFT; > + if (is_file_hugepages(memfd)) { > + hpstate = hstate_file(memfd); > + pgoff = list[i].offset >> huge_page_shift(hpstate); > + subpgoff = (list[i].offset & > + ~huge_page_mask(hpstate)) >> PAGE_SHIFT; > + maxsubpgs = huge_page_size(hpstate) >> PAGE_SHIFT; > + } > for (pgidx = 0; pgidx < pgcnt; pgidx++) { > - page = shmem_read_mapping_page( > - file_inode(memfd)->i_mapping, pgoff + pgidx); > - if (IS_ERR(page)) { > - ret = PTR_ERR(page); > - goto err; > + if (is_file_hugepages(memfd)) { > + if (!hpage) { > + hpage = find_get_page_flags( > + file_inode(memfd)->i_mapping, > + pgoff, FGP_ACCESSED); > + if (IS_ERR(hpage)) { > + ret = PTR_ERR(hpage); > + goto err; > + } > + } > + page = hpage + subpgoff; > + get_page(page); > + subpgoff++; > + if (subpgoff == maxsubpgs) { > + put_page(hpage); > + hpage = NULL; > + subpgoff = 0; > + pgoff++; > + } > + } else { > + page = shmem_read_mapping_page( > + file_inode(memfd)->i_mapping, > + pgoff + pgidx); > + if (IS_ERR(page)) { > + ret = PTR_ERR(page); > + goto err; > + } > } > ubuf->pages[pgbuf++] = page; > } > fput(memfd); > memfd = NULL; > + if (hpage) { > + put_page(hpage); > + hpage = NULL; > + } > } > > exp_info.ops = &udmabuf_ops; > -- > 2.30.2 >
On Tue, Jun 08, 2021 at 10:35:58AM -0700, Dongwon Kim wrote: > I see the number of entries in the list often exceeds list_limit > currently hardcoded to 1024 for full HD scanout resource (== > 1920*1080*4 bytes). Can we include a change to increase it to something > like 4096 or higher in this patch? Separate patch please (and maybe turn limits into module parameters while being at it). take care, Gerd
Hi, > + hpage = find_get_page_flags( checkpatch doesn't like that: -:76: CHECK:OPEN_ENDED_LINE: Lines should not end with a '(' > + page = shmem_read_mapping_page( Same here. take care, Gerd
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index db732f71e59a..2e02bbfe30fd 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -11,6 +11,7 @@ #include <linux/shmem_fs.h> #include <linux/slab.h> #include <linux/udmabuf.h> +#include <linux/hugetlb.h> static const u32 list_limit = 1024; /* udmabuf_create_list->count limit */ static const size_t size_limit_mb = 64; /* total dmabuf size, in megabytes */ @@ -163,7 +164,9 @@ static long udmabuf_create(struct miscdevice *device, struct udmabuf *ubuf; struct dma_buf *buf; pgoff_t pgoff, pgcnt, pgidx, pgbuf = 0, pglimit; - struct page *page; + struct page *page, *hpage = NULL; + pgoff_t subpgoff, maxsubpgs; + struct hstate *hpstate; int seals, ret = -EINVAL; u32 i, flags; @@ -194,7 +197,8 @@ static long udmabuf_create(struct miscdevice *device, memfd = fget(list[i].memfd); if (!memfd) goto err; - if (!shmem_mapping(file_inode(memfd)->i_mapping)) + if (!shmem_mapping(file_inode(memfd)->i_mapping) && + !is_file_hugepages(memfd)) goto err; seals = memfd_fcntl(memfd, F_GET_SEALS, 0); if (seals == -EINVAL) @@ -205,17 +209,50 @@ static long udmabuf_create(struct miscdevice *device, goto err; pgoff = list[i].offset >> PAGE_SHIFT; pgcnt = list[i].size >> PAGE_SHIFT; + if (is_file_hugepages(memfd)) { + hpstate = hstate_file(memfd); + pgoff = list[i].offset >> huge_page_shift(hpstate); + subpgoff = (list[i].offset & + ~huge_page_mask(hpstate)) >> PAGE_SHIFT; + maxsubpgs = huge_page_size(hpstate) >> PAGE_SHIFT; + } for (pgidx = 0; pgidx < pgcnt; pgidx++) { - page = shmem_read_mapping_page( - file_inode(memfd)->i_mapping, pgoff + pgidx); - if (IS_ERR(page)) { - ret = PTR_ERR(page); - goto err; + if (is_file_hugepages(memfd)) { + if (!hpage) { + hpage = find_get_page_flags( + file_inode(memfd)->i_mapping, + pgoff, FGP_ACCESSED); + if (IS_ERR(hpage)) { + ret = PTR_ERR(hpage); + goto err; + } + } + page = hpage + subpgoff; + get_page(page); + subpgoff++; + if (subpgoff == maxsubpgs) { + put_page(hpage); + hpage = NULL; + subpgoff = 0; + pgoff++; + } + } else { + page = shmem_read_mapping_page( + file_inode(memfd)->i_mapping, + pgoff + pgidx); + if (IS_ERR(page)) { + ret = PTR_ERR(page); + goto err; + } } ubuf->pages[pgbuf++] = page; } fput(memfd); memfd = NULL; + if (hpage) { + put_page(hpage); + hpage = NULL; + } } exp_info.ops = &udmabuf_ops;