[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v6 3/3] tools/libxc: use superpages during restore of HVM guest
During creating of a HVM domU meminit_hvm() tries to map superpages. After save/restore or migration this mapping is lost, everything is allocated in single pages. This causes a performance degradition after migration. Add neccessary code to preallocate a superpage for the chunk of pfns that is received. In case a pfn was not populated on the sending side it must be freed on the receiving side to avoid over-allocation. The existing code for x86_pv is moved unmodified into its own file. Signed-off-by: Olaf Hering <olaf@xxxxxxxxx> --- tools/libxc/xc_sr_common.h | 25 +++- tools/libxc/xc_sr_restore.c | 75 +--------- tools/libxc/xc_sr_restore_x86_hvm.c | 288 ++++++++++++++++++++++++++++++++++++ tools/libxc/xc_sr_restore_x86_pv.c | 72 ++++++++- 4 files changed, 382 insertions(+), 78 deletions(-) diff --git a/tools/libxc/xc_sr_common.h b/tools/libxc/xc_sr_common.h index da2691ba79..0fa0fbea4d 100644 --- a/tools/libxc/xc_sr_common.h +++ b/tools/libxc/xc_sr_common.h @@ -139,6 +139,16 @@ struct xc_sr_restore_ops */ int (*setup)(struct xc_sr_context *ctx); + /** + * Populate PFNs + * + * Given a set of pfns, obtain memory from Xen to fill the physmap for the + * unpopulated subset. + */ + int (*populate_pfns)(struct xc_sr_context *ctx, unsigned count, + const xen_pfn_t *original_pfns, const uint32_t *types); + + /** * Process an individual record from the stream. The caller shall take * care of processing common records (e.g. END, PAGE_DATA). @@ -224,6 +234,8 @@ struct xc_sr_context int send_back_fd; unsigned long p2m_size; + unsigned long max_pages; + unsigned long tot_pages; xc_hypercall_buffer_t dirty_bitmap_hbuf; /* From Image Header. */ @@ -336,6 +348,11 @@ struct xc_sr_context /* HVM context blob. */ void *context; size_t contextsz; + + /* Bitmap of currently allocated PFNs during restore. */ + struct xc_sr_bitmap attempted_1g; + struct xc_sr_bitmap attempted_2m; + struct xc_sr_bitmap allocated_pfns; } restore; }; } x86_hvm; @@ -455,14 +472,6 @@ static inline int write_record(struct xc_sr_context *ctx, */ int read_record(struct xc_sr_context *ctx, int fd, struct xc_sr_record *rec); -/* - * This would ideally be private in restore.c, but is needed by - * x86_pv_localise_page() if we receive pagetables frames ahead of the - * contents of the frames they point at. - */ -int populate_pfns(struct xc_sr_context *ctx, unsigned count, - const xen_pfn_t *original_pfns, const uint32_t *types); - #endif /* * Local variables: diff --git a/tools/libxc/xc_sr_restore.c b/tools/libxc/xc_sr_restore.c index d53948e1a6..8cd9289d1a 100644 --- a/tools/libxc/xc_sr_restore.c +++ b/tools/libxc/xc_sr_restore.c @@ -68,74 +68,6 @@ static int read_headers(struct xc_sr_context *ctx) return 0; } -/* - * Given a set of pfns, obtain memory from Xen to fill the physmap for the - * unpopulated subset. If types is NULL, no page type checking is performed - * and all unpopulated pfns are populated. - */ -int populate_pfns(struct xc_sr_context *ctx, unsigned count, - const xen_pfn_t *original_pfns, const uint32_t *types) -{ - xc_interface *xch = ctx->xch; - xen_pfn_t *mfns = malloc(count * sizeof(*mfns)), - *pfns = malloc(count * sizeof(*pfns)); - unsigned i, nr_pfns = 0; - int rc = -1; - - if ( !mfns || !pfns ) - { - ERROR("Failed to allocate %zu bytes for populating the physmap", - 2 * count * sizeof(*mfns)); - goto err; - } - - for ( i = 0; i < count; ++i ) - { - if ( (!types || (types && - (types[i] != XEN_DOMCTL_PFINFO_XTAB && - types[i] != XEN_DOMCTL_PFINFO_BROKEN))) && - !pfn_is_populated(ctx, original_pfns[i]) ) - { - rc = pfn_set_populated(ctx, original_pfns[i]); - if ( rc ) - goto err; - pfns[nr_pfns] = mfns[nr_pfns] = original_pfns[i]; - ++nr_pfns; - } - } - - if ( nr_pfns ) - { - rc = xc_domain_populate_physmap_exact( - xch, ctx->domid, nr_pfns, 0, 0, mfns); - if ( rc ) - { - PERROR("Failed to populate physmap"); - goto err; - } - - for ( i = 0; i < nr_pfns; ++i ) - { - if ( mfns[i] == INVALID_MFN ) - { - ERROR("Populate physmap failed for pfn %u", i); - rc = -1; - goto err; - } - - ctx->restore.ops.set_gfn(ctx, pfns[i], mfns[i]); - } - } - - rc = 0; - - err: - free(pfns); - free(mfns); - - return rc; -} - /* * Given a list of pfns, their types, and a block of page data from the * stream, populate and record their types, map the relevant subset and copy @@ -161,7 +93,7 @@ static int process_page_data(struct xc_sr_context *ctx, unsigned count, goto err; } - rc = populate_pfns(ctx, count, pfns, types); + rc = ctx->restore.ops.populate_pfns(ctx, count, pfns, types); if ( rc ) { ERROR("Failed to populate pfns for batch of %u pages", count); @@ -826,7 +758,12 @@ int xc_domain_restore(xc_interface *xch, int io_fd, uint32_t dom, return -1; } + /* See xc_domain_getinfo */ + ctx.restore.max_pages = ctx.dominfo.max_memkb >> (PAGE_SHIFT-10); + ctx.restore.tot_pages = ctx.dominfo.nr_pages; ctx.restore.p2m_size = nr_pfns; + DPRINTF("dom %u p2m_size %lx max_pages %lx", + ctx.domid, ctx.restore.p2m_size, ctx.restore.max_pages); if ( ctx.dominfo.hvm ) { diff --git a/tools/libxc/xc_sr_restore_x86_hvm.c b/tools/libxc/xc_sr_restore_x86_hvm.c index 1dca85354a..2b0eca0c7c 100644 --- a/tools/libxc/xc_sr_restore_x86_hvm.c +++ b/tools/libxc/xc_sr_restore_x86_hvm.c @@ -135,6 +135,8 @@ static int x86_hvm_localise_page(struct xc_sr_context *ctx, static int x86_hvm_setup(struct xc_sr_context *ctx) { xc_interface *xch = ctx->xch; + struct xc_sr_bitmap *bm; + unsigned long bits; if ( ctx->restore.guest_type != DHDR_TYPE_X86_HVM ) { @@ -149,7 +151,30 @@ static int x86_hvm_setup(struct xc_sr_context *ctx) return -1; } + bm = &ctx->x86_hvm.restore.attempted_1g; + bits = (ctx->restore.p2m_size >> SUPERPAGE_1GB_SHIFT) + 1; + if ( xc_sr_bitmap_resize(bm, bits) == false ) + goto out; + + bm = &ctx->x86_hvm.restore.attempted_2m; + bits = (ctx->restore.p2m_size >> SUPERPAGE_2MB_SHIFT) + 1; + if ( xc_sr_bitmap_resize(bm, bits) == false ) + goto out; + + bm = &ctx->x86_hvm.restore.allocated_pfns; + bits = ctx->restore.p2m_size + 1; + if ( xc_sr_bitmap_resize(bm, bits) == false ) + goto out; + + /* No superpage in 1st 2MB due to VGA hole */ + xc_sr_set_bit(0, &ctx->x86_hvm.restore.attempted_1g); + xc_sr_set_bit(0, &ctx->x86_hvm.restore.attempted_2m); + return 0; + +out: + ERROR("Unable to allocate memory for pfn bitmaps"); + return -1; } /* @@ -224,10 +249,272 @@ static int x86_hvm_stream_complete(struct xc_sr_context *ctx) static int x86_hvm_cleanup(struct xc_sr_context *ctx) { free(ctx->x86_hvm.restore.context); + xc_sr_bitmap_free(&ctx->x86_hvm.restore.attempted_1g); + xc_sr_bitmap_free(&ctx->x86_hvm.restore.attempted_2m); + xc_sr_bitmap_free(&ctx->x86_hvm.restore.allocated_pfns); return 0; } +/* + * Set a pfn as allocated, expanding the tracking structures if needed. + */ +static int pfn_set_allocated(struct xc_sr_context *ctx, xen_pfn_t pfn) +{ + xc_interface *xch = ctx->xch; + + if ( !xc_sr_set_bit(pfn, &ctx->x86_hvm.restore.allocated_pfns) ) + { + ERROR("Failed to realloc allocated_pfns bitmap"); + errno = ENOMEM; + return -1; + } + return 0; +} + +struct x86_hvm_sp { + xen_pfn_t pfn; + xen_pfn_t base_pfn; + unsigned long index; + unsigned long count; +}; + +/* + * Try to allocate a 1GB page for this pfn, but avoid Over-allocation. + * If this succeeds, mark the range of 2MB pages as busy. + */ +static bool x86_hvm_alloc_1g(struct xc_sr_context *ctx, struct x86_hvm_sp *sp) +{ + xc_interface *xch = ctx->xch; + struct xc_sr_bitmap *bm; + unsigned int order, shift; + int i, done; + xen_pfn_t extent; + + bm = &ctx->x86_hvm.restore.attempted_1g; + + /* Only one attempt to avoid overlapping allocation */ + if ( xc_sr_test_and_set_bit(sp->index, bm) ) + return false; + + order = SUPERPAGE_1GB_SHIFT; + sp->count = 1ULL << order; + + /* Allocate only if there is room for another superpage */ + if ( ctx->restore.tot_pages + sp->count > ctx->restore.max_pages ) + return false; + + extent = sp->base_pfn = (sp->pfn >> order) << order; + done = xc_domain_populate_physmap(xch, ctx->domid, 1, order, 0, &extent); + if ( done < 0 ) { + PERROR("populate_physmap failed."); + return false; + } + if ( done == 0 ) + return false; + + DPRINTF("1G base_pfn %" PRI_xen_pfn "\n", sp->base_pfn); + + /* Mark all 2MB pages as done to avoid overlapping allocation */ + bm = &ctx->x86_hvm.restore.attempted_2m; + shift = SUPERPAGE_1GB_SHIFT - SUPERPAGE_2MB_SHIFT; + for ( i = 0; i < (sp->count >> shift); i++ ) + xc_sr_set_bit((sp->base_pfn >> SUPERPAGE_2MB_SHIFT) + i, bm); + + return true; +} + +/* Allocate a 2MB page if x86_hvm_alloc_1g failed, avoid Over-allocation. */ +static bool x86_hvm_alloc_2m(struct xc_sr_context *ctx, struct x86_hvm_sp *sp) +{ + xc_interface *xch = ctx->xch; + struct xc_sr_bitmap *bm; + unsigned int order; + int done; + xen_pfn_t extent; + + bm = &ctx->x86_hvm.restore.attempted_2m; + + /* Only one attempt to avoid overlapping allocation */ + if ( xc_sr_test_and_set_bit(sp->index, bm) ) + return false; + + order = SUPERPAGE_2MB_SHIFT; + sp->count = 1ULL << order; + + /* Allocate only if there is room for another superpage */ + if ( ctx->restore.tot_pages + sp->count > ctx->restore.max_pages ) + return false; + + extent = sp->base_pfn = (sp->pfn >> order) << order; + done = xc_domain_populate_physmap(xch, ctx->domid, 1, order, 0, &extent); + if ( done < 0 ) { + PERROR("populate_physmap failed."); + return false; + } + if ( done == 0 ) + return false; + + DPRINTF("2M base_pfn %" PRI_xen_pfn "\n", sp->base_pfn); + return true; +} + +/* Allocate a single page if x86_hvm_alloc_2m failed. */ +static bool x86_hvm_alloc_4k(struct xc_sr_context *ctx, struct x86_hvm_sp *sp) +{ + xc_interface *xch = ctx->xch; + unsigned int order; + int done; + xen_pfn_t extent; + + order = 0; + sp->count = 1ULL << order; + + /* Allocate only if there is room for another page */ + if ( ctx->restore.tot_pages + sp->count > ctx->restore.max_pages ) + return false; + + extent = sp->base_pfn = (sp->pfn >> order) << order; + done = xc_domain_populate_physmap(xch, ctx->domid, 1, order, 0, &extent); + if ( done < 0 ) { + PERROR("populate_physmap failed."); + return false; + } + if ( done == 0 ) + return false; + + DPRINTF("4K base_pfn %" PRI_xen_pfn "\n", sp->base_pfn); + return true; +} +/* + * Attempt to allocate a superpage where the pfn resides. + */ +static int x86_hvm_allocate_pfn(struct xc_sr_context *ctx, xen_pfn_t pfn) +{ + xc_interface *xch = ctx->xch; + bool success; + int rc = -1; + unsigned long idx_1g, idx_2m; + struct x86_hvm_sp sp = { + .pfn = pfn + }; + + if ( xc_sr_test_bit(pfn, &ctx->x86_hvm.restore.allocated_pfns) ) + return 0; + + idx_1g = pfn >> SUPERPAGE_1GB_SHIFT; + idx_2m = pfn >> SUPERPAGE_2MB_SHIFT; + if ( !xc_sr_bitmap_resize(&ctx->x86_hvm.restore.attempted_1g, idx_1g) ) + { + PERROR("Failed to realloc attempted_1g"); + return -1; + } + if ( !xc_sr_bitmap_resize(&ctx->x86_hvm.restore.attempted_2m, idx_2m) ) + { + PERROR("Failed to realloc attempted_2m"); + return -1; + } + + sp.index = idx_1g; + success = x86_hvm_alloc_1g(ctx, &sp); + + if ( success == false ) { + sp.index = idx_2m; + success = x86_hvm_alloc_2m(ctx, &sp); + } + + if ( success == false ) { + sp.index = 0; + success = x86_hvm_alloc_4k(ctx, &sp); + } + + if ( success == true ) { + do { + sp.count--; + ctx->restore.tot_pages++; + rc = pfn_set_allocated(ctx, sp.base_pfn + sp.count); + if ( rc ) + break; + } while ( sp.count ); + } + return rc; +} + +static int x86_hvm_populate_pfns(struct xc_sr_context *ctx, unsigned count, + const xen_pfn_t *original_pfns, + const uint32_t *types) +{ + xc_interface *xch = ctx->xch; + xen_pfn_t pfn, min_pfn = original_pfns[0], max_pfn = original_pfns[0]; + unsigned i, freed = 0, order; + int rc = -1; + + for ( i = 0; i < count; ++i ) + { + if ( original_pfns[i] < min_pfn ) + min_pfn = original_pfns[i]; + if ( original_pfns[i] > max_pfn ) + max_pfn = original_pfns[i]; + } + DPRINTF("batch of %u pfns between %" PRI_xen_pfn " %" PRI_xen_pfn "\n", + count, min_pfn, max_pfn); + + for ( i = 0; i < count; ++i ) + { + if ( (types[i] != XEN_DOMCTL_PFINFO_XTAB && + types[i] != XEN_DOMCTL_PFINFO_BROKEN) && + !pfn_is_populated(ctx, original_pfns[i]) ) + { + rc = x86_hvm_allocate_pfn(ctx, original_pfns[i]); + if ( rc ) + goto err; + rc = pfn_set_populated(ctx, original_pfns[i]); + if ( rc ) + goto err; + } + } + + /* + * Scan the entire superpage because several batches will fit into + * a superpage, and it is unknown which pfn triggered the allocation. + */ + order = SUPERPAGE_1GB_SHIFT; + pfn = min_pfn = (min_pfn >> order) << order; + + while ( pfn <= max_pfn ) + { + struct xc_sr_bitmap *bm; + bm = &ctx->x86_hvm.restore.allocated_pfns; + if ( !xc_sr_bitmap_resize(bm, pfn) ) + { + PERROR("Failed to realloc allocated_pfns %" PRI_xen_pfn, pfn); + goto err; + } + if ( !pfn_is_populated(ctx, pfn) && + xc_sr_test_and_clear_bit(pfn, bm) ) { + xen_pfn_t p = pfn; + rc = xc_domain_decrease_reservation_exact(xch, ctx->domid, 1, 0, &p); + if ( rc ) + { + PERROR("Failed to release pfn %" PRI_xen_pfn, pfn); + goto err; + } + ctx->restore.tot_pages--; + freed++; + } + pfn++; + } + if ( freed ) + DPRINTF("freed %u between %" PRI_xen_pfn " %" PRI_xen_pfn "\n", + freed, min_pfn, max_pfn); + + rc = 0; + + err: + return rc; +} + + struct xc_sr_restore_ops restore_ops_x86_hvm = { .pfn_is_valid = x86_hvm_pfn_is_valid, @@ -236,6 +523,7 @@ struct xc_sr_restore_ops restore_ops_x86_hvm = .set_page_type = x86_hvm_set_page_type, .localise_page = x86_hvm_localise_page, .setup = x86_hvm_setup, + .populate_pfns = x86_hvm_populate_pfns, .process_record = x86_hvm_process_record, .stream_complete = x86_hvm_stream_complete, .cleanup = x86_hvm_cleanup, diff --git a/tools/libxc/xc_sr_restore_x86_pv.c b/tools/libxc/xc_sr_restore_x86_pv.c index 50e25c162c..87957559bc 100644 --- a/tools/libxc/xc_sr_restore_x86_pv.c +++ b/tools/libxc/xc_sr_restore_x86_pv.c @@ -936,6 +936,75 @@ static void x86_pv_set_gfn(struct xc_sr_context *ctx, xen_pfn_t pfn, ((uint32_t *)ctx->x86_pv.p2m)[pfn] = mfn; } +/* + * Given a set of pfns, obtain memory from Xen to fill the physmap for the + * unpopulated subset. If types is NULL, no page type checking is performed + * and all unpopulated pfns are populated. + */ +static int x86_pv_populate_pfns(struct xc_sr_context *ctx, unsigned count, + const xen_pfn_t *original_pfns, + const uint32_t *types) +{ + xc_interface *xch = ctx->xch; + xen_pfn_t *mfns = malloc(count * sizeof(*mfns)), + *pfns = malloc(count * sizeof(*pfns)); + unsigned i, nr_pfns = 0; + int rc = -1; + + if ( !mfns || !pfns ) + { + ERROR("Failed to allocate %zu bytes for populating the physmap", + 2 * count * sizeof(*mfns)); + goto err; + } + + for ( i = 0; i < count; ++i ) + { + if ( (!types || (types && + (types[i] != XEN_DOMCTL_PFINFO_XTAB && + types[i] != XEN_DOMCTL_PFINFO_BROKEN))) && + !pfn_is_populated(ctx, original_pfns[i]) ) + { + rc = pfn_set_populated(ctx, original_pfns[i]); + if ( rc ) + goto err; + pfns[nr_pfns] = mfns[nr_pfns] = original_pfns[i]; + ++nr_pfns; + } + } + + if ( nr_pfns ) + { + rc = xc_domain_populate_physmap_exact( + xch, ctx->domid, nr_pfns, 0, 0, mfns); + if ( rc ) + { + PERROR("Failed to populate physmap"); + goto err; + } + + for ( i = 0; i < nr_pfns; ++i ) + { + if ( mfns[i] == INVALID_MFN ) + { + ERROR("Populate physmap failed for pfn %u", i); + rc = -1; + goto err; + } + + ctx->restore.ops.set_gfn(ctx, pfns[i], mfns[i]); + } + } + + rc = 0; + + err: + free(pfns); + free(mfns); + + return rc; +} + /* * restore_ops function. Convert pfns back to mfns in pagetables. Possibly * needs to populate new frames if a PTE is found referring to a frame which @@ -980,7 +1049,7 @@ static int x86_pv_localise_page(struct xc_sr_context *ctx, } } - if ( to_populate && populate_pfns(ctx, to_populate, pfns, NULL) ) + if ( to_populate && x86_pv_populate_pfns(ctx, to_populate, pfns, NULL) ) return -1; for ( i = 0; i < (PAGE_SIZE / sizeof(uint64_t)); ++i ) @@ -1160,6 +1229,7 @@ struct xc_sr_restore_ops restore_ops_x86_pv = .set_gfn = x86_pv_set_gfn, .localise_page = x86_pv_localise_page, .setup = x86_pv_setup, + .populate_pfns = x86_pv_populate_pfns, .process_record = x86_pv_process_record, .stream_complete = x86_pv_stream_complete, .cleanup = x86_pv_cleanup, _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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