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2017-01-26hbitmap: Add hbitmap_is_serializable()Max Reitz1-3/+19
Bitmaps with a granularity of 58 or above can be neither serialized nor deserialized (see the comment in the function added in this series for an explanation). This patch adds a function so that we can check whether a bitmap actually can be (de-)serialized at all, thus avoiding failing the necessary assertion in hbitmap_serialization_granularity(). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20161115225746.3590-2-mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
2016-11-29hbitmap: Fix shifts of constants by granularityMax Reitz1-2/+6
An hbitmap's granularity may be anything from 0 to 63, so when shifting constants by its value, they should not be plain ints. Even having changed the types, hbitmap_serialization_granularity() still tries to shift 64 to the right by the granularity. This operation is undefined if the granularity is greater than 57. Adding an assertion is fine for now, because serializing is done only in tests so far, but this means that only bitmaps with a granularity below 58 can be serialized and we should thus add a hbitmap_is_serializable() function later. One of the two places touched in this patch uses QEMU_ALIGN_UP(x, 1 << y). We can use ROUND_UP() there, since the second parameter is obviously a power of two. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20161115224732.1334-1-mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
2016-10-24hbitmap: serializationVladimir Sementsov-Ogievskiy1-0/+137
Functions to serialize / deserialize(restore) HBitmap. HBitmap should be saved to linear sequence of bits independently of endianness and bitmap array element (unsigned long) size. Therefore Little Endian is chosen. These functions are appropriate for dirty bitmap migration, restoring the bitmap in several steps is available. To save performance, every step writes only the last level of the bitmap. All other levels are restored by hbitmap_deserialize_finish() as a last step of restoring. So, HBitmap is inconsistent while restoring. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [Fix left shift operand to 1UL; add "finish" parameter. - Fam] Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 1476395910-8697-8-git-send-email-jsnow@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-10-24HBitmap: Introduce "meta" bitmap to track bit changesFam Zheng1-15/+54
Upon each bit toggle, the corresponding bit in the meta bitmap will be set. Signed-off-by: Fam Zheng <famz@redhat.com> [Amended text inline. --js] Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 1476395910-8697-3-git-send-email-jsnow@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-06-16hbitmap: add 'pos < size' assertsVladimir Sementsov-Ogievskiy1-0/+3
For now, fail in hbitmap_set on start + count > size will come from hbitmap_set hb_count_between hbitmap_iter_init assert(pos < hb->size) This patch adds such checks to set/get/reset functions of hbitmap. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 1465924093-76875-2-git-send-email-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-06-07all: Remove unnecessary glib.h includesPeter Maydell1-1/+0
Remove glib.h includes, as it is provided by osdep.h. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2016-02-04util: Clean up includesPeter Maydell1-3/+1
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1454089805-5470-6-git-send-email-peter.maydell@linaro.org
2015-06-23util/hbitmap: Add an API to reset all set bits in hbitmapWen Congyang1-0/+13
The function bdrv_clear_dirty_bitmap() is updated to use faster hbitmap_reset_all() call. Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> Signed-off-by: Gonglei <arei.gonglei@huawei.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 555E868A.60506@cn.fujitsu.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-04-28block: Resize bitmaps on bdrv_truncateJohn Snow1-0/+48
Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1429314609-29776-16-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28hbitmap: add hbitmap_mergeJohn Snow1-0/+33
We add a bitmap merge operation to assist in error cases where we wish to combine two bitmaps together. This is algorithmically O(bits) provided HBITMAP_LEVELS remains constant. For a full bitmap on a 64bit machine: sum(bits/64^k, k, 0, HBITMAP_LEVELS) ~= 1.01587 * bits We may be able to improve running speed for particularly sparse bitmaps by using iterators, but the running time for dense maps will be worse. We present the simpler solution first, and we can refine it later if needed. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1429314609-29776-8-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-04-28hbitmap: cache array lengthsJohn Snow1-0/+4
As a convenience: between incremental backups, bitmap migrations and bitmap persistence we seem to need to recalculate these a lot. Because the lengths are a little bit-twiddly, let's just solidly cache them and be done with it. Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1429314609-29776-7-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10util: Use g_new() & friends where that makes obvious senseMarkus Armbruster1-2/+2
g_new(T, n) is neater than g_malloc(sizeof(T) * n). It's also safer, for two reasons. One, it catches multiplication overflowing size_t. Two, it returns T * rather than void *, which lets the compiler catch more type errors. This commit only touches allocations with size arguments of the form sizeof(T). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2014-06-11util/hbitmap.c: Use ctpopl rather than reimplementing a local equivalentPeter Maydell1-7/+2
The function popcountl() in hbitmap.c is effectively a reimplementation of what host-utils.h provides as ctpopl(). Use ctpopl() directly; this fixes a failure to compile on NetBSD (whose strings.h erroneously exposes a system popcountl() which clashes with this one). Reported-by: Martin Husemann <martin@duskware.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2013-02-16hbitmap: Use non-bitops ctzlRichard Henderson1-1/+2
Both uses of ctz have already eliminated zero, and thus the difference in edge conditions between the two routines is irrelevant. Signed-off-by: Richard Henderson <rth@twiddle.net> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-02-02bitops: unify bitops_ffsl with the one in host-utils.h, call it bitops_ctzlPaolo Bonzini1-1/+1
We had two copies of a ffs function for longs with subtly different semantics and, for the one in bitops.h, a confusing name: the result was off-by-one compared to the library function ffsl. Unify the functions into one, and solve the name problem by calling the 0-based functions "bitops_ctzl" and "bitops_ctol" respectively. This also fixes the build on platforms with ffsl, including Mac OS X and Windows. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Andreas Färber <afaerber@suse.de> Tested-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2013-01-25hbitmap: add assertion on hbitmap_iter_initPaolo Bonzini1-0/+1
hbitmap_iter_init causes an out-of-bounds access when the "first" argument is or greater than or equal to the size of the bitmap. Forbid this with an assertion, and remove the failing testcase. Reported-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-01-25add hierarchical bitmap data type and test casesPaolo Bonzini1-0/+400
HBitmaps provides an array of bits. The bits are stored as usual in an array of unsigned longs, but HBitmap is also optimized to provide fast iteration over set bits; going from one bit to the next is O(logB n) worst case, with B = sizeof(long) * CHAR_BIT: the result is low enough that the number of levels is in fact fixed. In order to do this, it stacks multiple bitmaps with progressively coarser granularity; in all levels except the last, bit N is set iff the N-th unsigned long is nonzero in the immediately next level. When iteration completes on the last level it can examine the 2nd-last level to quickly skip entire words, and even do so recursively to skip blocks of 64 words or powers thereof (32 on 32-bit machines). Given an index in the bitmap, it can be split in group of bits like this (for the 64-bit case): bits 0-57 => word in the last bitmap | bits 58-63 => bit in the word bits 0-51 => word in the 2nd-last bitmap | bits 52-57 => bit in the word bits 0-45 => word in the 3rd-last bitmap | bits 46-51 => bit in the word So it is easy to move up simply by shifting the index right by log2(BITS_PER_LONG) bits. To move down, you shift the index left similarly, and add the word index within the group. Iteration uses ffs (find first set bit) to find the next word to examine; this operation can be done in constant time in most current architectures. Setting or clearing a range of m bits on all levels, the work to perform is O(m + m/W + m/W^2 + ...), which is O(m) like on a regular bitmap. When iterating on a bitmap, each bit (on any level) is only visited once. Hence, The total cost of visiting a bitmap with m bits in it is the number of bits that are set in all bitmaps. Unless the bitmap is extremely sparse, this is also O(m + m/W + m/W^2 + ...), so the amortized cost of advancing from one bit to the next is usually constant. Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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