From patchwork Thu Oct 13 21:58:22 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Snow X-Patchwork-Id: 9375865 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A22A7607FD for ; Thu, 13 Oct 2016 22:03:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 931C02A0AB for ; Thu, 13 Oct 2016 22:03:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 87F392A111; Thu, 13 Oct 2016 22:03:59 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id EA8DA2A0AB for ; Thu, 13 Oct 2016 22:03:58 +0000 (UTC) Received: from localhost ([::1]:43244 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buo6Y-0000mK-32 for patchwork-qemu-devel@patchwork.kernel.org; Thu, 13 Oct 2016 18:03:58 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42029) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buo1U-0005Iz-S4 for qemu-devel@nongnu.org; Thu, 13 Oct 2016 17:58:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1buo1T-0006GX-74 for qemu-devel@nongnu.org; Thu, 13 Oct 2016 17:58:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35248) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buo1M-0006AR-Fw; Thu, 13 Oct 2016 17:58:36 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CCB0E8F895; Thu, 13 Oct 2016 21:58:35 +0000 (UTC) Received: from scv.usersys.redhat.com (dhcp-17-171.bos.redhat.com [10.18.17.171]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u9DLwWGf008454; Thu, 13 Oct 2016 17:58:35 -0400 From: John Snow To: qemu-block@nongnu.org Date: Thu, 13 Oct 2016 17:58:22 -0400 Message-Id: <1476395910-8697-3-git-send-email-jsnow@redhat.com> In-Reply-To: <1476395910-8697-1-git-send-email-jsnow@redhat.com> References: <1476395910-8697-1-git-send-email-jsnow@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 13 Oct 2016 21:58:35 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v10 02/10] HBitmap: Introduce "meta" bitmap to track bit changes X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: John Snow , vsementsov@virtuozzo.com, famz@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Fam Zheng Upon each bit toggle, the corresponding bit in the meta bitmap will be set. Signed-off-by: Fam Zheng [Amended text inline. --js] Reviewed-by: Max Reitz Signed-off-by: John Snow --- include/qemu/hbitmap.h | 21 +++++++++++++++ util/hbitmap.c | 69 +++++++++++++++++++++++++++++++++++++++----------- 2 files changed, 75 insertions(+), 15 deletions(-) diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h index 8ab721e..1725919 100644 --- a/include/qemu/hbitmap.h +++ b/include/qemu/hbitmap.h @@ -178,6 +178,27 @@ void hbitmap_iter_init(HBitmapIter *hbi, const HBitmap *hb, uint64_t first); */ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi); +/* hbitmap_create_meta: + * Create a "meta" hbitmap to track dirtiness of the bits in this HBitmap. + * The caller owns the created bitmap and must call hbitmap_free_meta(hb) to + * free it. + * + * Currently, we only guarantee that if a bit in the hbitmap is changed it + * will be reflected in the meta bitmap, but we do not yet guarantee the + * opposite. + * + * @hb: The HBitmap to operate on. + * @chunk_size: How many bits in @hb does one bit in the meta track. + */ +HBitmap *hbitmap_create_meta(HBitmap *hb, int chunk_size); + +/* hbitmap_free_meta: + * Free the meta bitmap of @hb. + * + * @hb: The HBitmap whose meta bitmap should be freed. + */ +void hbitmap_free_meta(HBitmap *hb); + /** * hbitmap_iter_next: * @hbi: HBitmapIter to operate on. diff --git a/util/hbitmap.c b/util/hbitmap.c index 99fd2ba..f303975 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -78,6 +78,9 @@ struct HBitmap { */ int granularity; + /* A meta dirty bitmap to track the dirtiness of bits in this HBitmap. */ + HBitmap *meta; + /* A number of progressively less coarse bitmaps (i.e. level 0 is the * coarsest). Each bit in level N represents a word in level N+1 that * has a set bit, except the last level where each bit represents the @@ -209,25 +212,27 @@ static uint64_t hb_count_between(HBitmap *hb, uint64_t start, uint64_t last) } /* Setting starts at the last layer and propagates up if an element - * changes from zero to non-zero. + * changes. */ static inline bool hb_set_elem(unsigned long *elem, uint64_t start, uint64_t last) { unsigned long mask; - bool changed; + unsigned long old; assert((last >> BITS_PER_LEVEL) == (start >> BITS_PER_LEVEL)); assert(start <= last); mask = 2UL << (last & (BITS_PER_LONG - 1)); mask -= 1UL << (start & (BITS_PER_LONG - 1)); - changed = (*elem == 0); + old = *elem; *elem |= mask; - return changed; + return old != *elem; } -/* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... */ -static void hb_set_between(HBitmap *hb, int level, uint64_t start, uint64_t last) +/* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... + * Returns true if at least one bit is changed. */ +static bool hb_set_between(HBitmap *hb, int level, uint64_t start, + uint64_t last) { size_t pos = start >> BITS_PER_LEVEL; size_t lastpos = last >> BITS_PER_LEVEL; @@ -256,23 +261,28 @@ static void hb_set_between(HBitmap *hb, int level, uint64_t start, uint64_t last if (level > 0 && changed) { hb_set_between(hb, level - 1, pos, lastpos); } + return changed; } void hbitmap_set(HBitmap *hb, uint64_t start, uint64_t count) { /* Compute range in the last layer. */ + uint64_t first, n; uint64_t last = start + count - 1; trace_hbitmap_set(hb, start, count, start >> hb->granularity, last >> hb->granularity); - start >>= hb->granularity; + first = start >> hb->granularity; last >>= hb->granularity; - count = last - start + 1; assert(last < hb->size); + n = last - first + 1; - hb->count += count - hb_count_between(hb, start, last); - hb_set_between(hb, HBITMAP_LEVELS - 1, start, last); + hb->count += n - hb_count_between(hb, first, last); + if (hb_set_between(hb, HBITMAP_LEVELS - 1, first, last) && + hb->meta) { + hbitmap_set(hb->meta, start, count); + } } /* Resetting works the other way round: propagate up if the new @@ -293,8 +303,10 @@ static inline bool hb_reset_elem(unsigned long *elem, uint64_t start, uint64_t l return blanked; } -/* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... */ -static void hb_reset_between(HBitmap *hb, int level, uint64_t start, uint64_t last) +/* The recursive workhorse (the depth is limited to HBITMAP_LEVELS)... + * Returns true if at least one bit is changed. */ +static bool hb_reset_between(HBitmap *hb, int level, uint64_t start, + uint64_t last) { size_t pos = start >> BITS_PER_LEVEL; size_t lastpos = last >> BITS_PER_LEVEL; @@ -337,22 +349,29 @@ static void hb_reset_between(HBitmap *hb, int level, uint64_t start, uint64_t la if (level > 0 && changed) { hb_reset_between(hb, level - 1, pos, lastpos); } + + return changed; + } void hbitmap_reset(HBitmap *hb, uint64_t start, uint64_t count) { /* Compute range in the last layer. */ + uint64_t first; uint64_t last = start + count - 1; trace_hbitmap_reset(hb, start, count, start >> hb->granularity, last >> hb->granularity); - start >>= hb->granularity; + first = start >> hb->granularity; last >>= hb->granularity; assert(last < hb->size); - hb->count -= hb_count_between(hb, start, last); - hb_reset_between(hb, HBITMAP_LEVELS - 1, start, last); + hb->count -= hb_count_between(hb, first, last); + if (hb_reset_between(hb, HBITMAP_LEVELS - 1, first, last) && + hb->meta) { + hbitmap_set(hb->meta, start, count); + } } void hbitmap_reset_all(HBitmap *hb) @@ -381,6 +400,7 @@ bool hbitmap_get(const HBitmap *hb, uint64_t item) void hbitmap_free(HBitmap *hb) { unsigned i; + assert(!hb->meta); for (i = HBITMAP_LEVELS; i-- > 0; ) { g_free(hb->levels[i]); } @@ -458,6 +478,9 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size) (size - old) * sizeof(*hb->levels[i])); } } + if (hb->meta) { + hbitmap_truncate(hb->meta, hb->size << hb->granularity); + } } @@ -493,3 +516,19 @@ bool hbitmap_merge(HBitmap *a, const HBitmap *b) return true; } + +HBitmap *hbitmap_create_meta(HBitmap *hb, int chunk_size) +{ + assert(!(chunk_size & (chunk_size - 1))); + assert(!hb->meta); + hb->meta = hbitmap_alloc(hb->size << hb->granularity, + hb->granularity + ctz32(chunk_size)); + return hb->meta; +} + +void hbitmap_free_meta(HBitmap *hb) +{ + assert(hb->meta); + hbitmap_free(hb->meta); + hb->meta = NULL; +}