On 10/6/2025 8:06 AM, Stanislav Kinsburskii wrote: > Reduce overhead when unmapping large memory regions by batching GPA unmap > operations in 2MB-aligned chunks. > > Use a dedicated constant for batch size to improve code clarity and > maintainability. > > Signed-off-by: Stanislav Kinsburskii <[email protected]> > --- > drivers/hv/mshv_root.h | 2 ++ > drivers/hv/mshv_root_hv_call.c | 2 +- > drivers/hv/mshv_root_main.c | 28 +++++++++++++++++++++++++--- > 3 files changed, 28 insertions(+), 4 deletions(-) > > diff --git a/drivers/hv/mshv_root.h b/drivers/hv/mshv_root.h > index e3931b0f12693..97e64d5341b6e 100644 > --- a/drivers/hv/mshv_root.h > +++ b/drivers/hv/mshv_root.h > @@ -32,6 +32,8 @@ static_assert(HV_HYP_PAGE_SIZE == MSHV_HV_PAGE_SIZE); > > #define MSHV_PIN_PAGES_BATCH_SIZE (0x10000000ULL / HV_HYP_PAGE_SIZE) > > +#define MSHV_MAX_UNMAP_GPA_PAGES 512 > + > struct mshv_vp { > u32 vp_index; > struct mshv_partition *vp_partition; > diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c > index c9c274f29c3c6..0696024ccfe31 100644 > --- a/drivers/hv/mshv_root_hv_call.c > +++ b/drivers/hv/mshv_root_hv_call.c > @@ -17,7 +17,7 @@ > /* Determined empirically */ > #define HV_INIT_PARTITION_DEPOSIT_PAGES 208 > #define HV_MAP_GPA_DEPOSIT_PAGES 256 > -#define HV_UMAP_GPA_PAGES 512 > +#define HV_UMAP_GPA_PAGES MSHV_MAX_UNMAP_GPA_PAGES > > #define HV_PAGE_COUNT_2M_ALIGNED(pg_count) (!((pg_count) & (0x200 - 1))) > > diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c > index 97e322f3c6b5e..b61bef6b9c132 100644 > --- a/drivers/hv/mshv_root_main.c > +++ b/drivers/hv/mshv_root_main.c > @@ -1378,6 +1378,7 @@ mshv_map_user_memory(struct mshv_partition *partition, > static void mshv_partition_destroy_region(struct mshv_mem_region *region) > { > struct mshv_partition *partition = region->partition; > + u64 gfn, gfn_count, start_gfn, end_gfn; > u32 unmap_flags = 0; > int ret; > > @@ -1396,9 +1397,30 @@ static void mshv_partition_destroy_region(struct > mshv_mem_region *region) > if (region->flags.large_pages) > unmap_flags |= HV_UNMAP_GPA_LARGE_PAGE; > > - /* ignore unmap failures and continue as process may be exiting */ > - hv_call_unmap_gpa_pages(partition->pt_id, region->start_gfn, > - region->nr_pages, unmap_flags); > + start_gfn = region->start_gfn; > + end_gfn = region->start_gfn + region->nr_pages; > + > + for (gfn = start_gfn; gfn < end_gfn; gfn += gfn_count) { > + if (gfn % MSHV_MAX_UNMAP_GPA_PAGES) > + gfn_count = ALIGN(gfn, MSHV_MAX_UNMAP_GPA_PAGES) - gfn; > + else > + gfn_count = MSHV_MAX_UNMAP_GPA_PAGES; > + > + if (gfn + gfn_count > end_gfn) > + gfn_count = end_gfn - gfn; > + > + /* Skip if all pages in this range if none is mapped */
nit: comment grammar. Suggest "Skip all pages in this range if none are mapped" Looks good otherwise. Reviewed-by: Nuno Das Neves <[email protected]> > + if (!memchr_inv(region->pages + (gfn - start_gfn), 0, > + gfn_count * sizeof(struct page *))) > + continue; > + > + ret = hv_call_unmap_gpa_pages(partition->pt_id, gfn, > + gfn_count, unmap_flags); > + if (ret) > + pt_err(partition, > + "Failed to unmap GPA pages %#llx-%#llx: %d\n", > + gfn, gfn + gfn_count - 1, ret); > + } > > mshv_region_invalidate(region); > > >
