Looks very good, I have several minor suggestions below (inline), but I would have committed this patch anyway, except that I didn't understand is why this patch is titled "2/2" - where is 1/2? I couldn't find it.
I see you have new realloc() tests - did these tests fail before your patches? -- Nadav Har'El [email protected] On Thu, Mar 26, 2020 at 8:36 PM Waldemar Kozaczuk <[email protected]> wrote: > This patch mostly addresses the issue #854. In essence it changes > malloc_large() > to use mmu::map_anon() if requested memory is greater than size of "huge > page" > and it does not have be contiguous in physical memory. Also it makes it > fallback > to map_anon() based allocation for requests > 4K and < 2MB that cannot be > satisfied > when memory is heavily fragmented. > > It is supposed to help OSv memory allocation behave better when memory > in free_page_ranges is heavily fragmented and large allocations (>=2MB) > cannot be satisfied with single contiguous page range. When working on > this patch it has also become clear, that applications that heavily use > realloc() > which allocates new chunks of memory and frees old ones, might very much > encounter > heavy fragmentation of memory. Hopefully this patch is going to help > in these scenarios. > > It just happens that object_size() and large_object_size() needed to be > adjusted to work with new malloc_large() implementation. It was discovered > that therefore other related issues are fixed by this patch as well. > > Fixes #854 > Fixed #1077 > > This patch also potentially addresses realloc() related issue #784. > It seems very likely it does address this as well. Maybe we should just close this issue too, because we're never going to get more information about this issue. > Lastly this patch adds new test verifying realloc() and > malloc_usable_size(). > > Signed-off-by: Waldemar Kozaczuk <[email protected]> > --- > core/mempool.cc | 66 +++++++++++++++++++++++------ > modules/tests/Makefile | 2 +- > tests/tst-realloc.cc | 94 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 149 insertions(+), 13 deletions(-) > create mode 100644 tests/tst-realloc.cc > > diff --git a/core/mempool.cc b/core/mempool.cc > index 11fd1456..1bf010d6 100644 > --- a/core/mempool.cc > +++ b/core/mempool.cc > @@ -546,7 +546,7 @@ public: > page_range_allocator() : _deferred_free(nullptr) { } > > template<bool UseBitmap = true> > - page_range* alloc(size_t size); > + page_range* alloc(size_t size, bool contiguous = true); > page_range* alloc_aligned(size_t size, size_t offset, size_t > alignment, > bool fill = false); > void free(page_range* pr); > @@ -678,7 +678,7 @@ void > page_range_allocator::bitmap_allocator<T>::deallocate(T* p, size_t n) > } > > template<bool UseBitmap> > -page_range* page_range_allocator::alloc(size_t size) > +page_range* page_range_allocator::alloc(size_t size, bool contiguous) > { > auto exact_order = ilog2_roundup(size / page_size); > if (exact_order > max_order) { > @@ -692,13 +692,12 @@ page_range* page_range_allocator::alloc(size_t size) > > page_range* range = nullptr; > if (!bitset) { > - if (!exact_order || _free[exact_order - 1].empty()) { > + if (!contiguous || !exact_order || _free[exact_order - > 1].empty()) { > return nullptr; > } > - // TODO: This linear search makes worst case complexity of the > allocator > - // O(n). It would be better to fall back to non-contiguous > allocation > - // and make worst case complexity depend on the size of requested > memory > - // block and the logarithm of the number of free huge page ranges. > + // This linear search makes worst case complexity of the allocator > + // O(n). Unfortunately we do not have choice for contiguous > allocation > + // so let us hope there is large enough range. > for (auto&& pr : _free[exact_order - 1]) { > if (pr.size >= size) { > range = ≺ > @@ -823,7 +822,16 @@ void page_range_allocator::for_each(unsigned > min_order, Func f) > } > } > > -static void* malloc_large(size_t size, size_t alignment, bool block = > true) > +static void* mapped_malloc_large(size_t size, size_t offset) > +{ > + //TODO: For now pre-populate the memory, in future consider doing > lazy population > + void* obj = mmu::map_anon(nullptr, size, mmu::mmap_populate, > mmu::perm_read | mmu::perm_write); > + size_t* ret_header = static_cast<size_t*>(obj); > + *ret_header = size; > + return obj + offset; > +} > + > +static void* malloc_large(size_t size, size_t alignment, bool block = > true, bool contiguous = true) > { > auto requested_size = size; > size_t offset; > @@ -835,6 +843,14 @@ static void* malloc_large(size_t size, size_t > alignment, bool block = true) > size += offset; > size = align_up(size, page_size); > > + // Use mmap if requested memory greater than "huge page" size > + // and does not need to be contiguous > + if (size >= mmu::huge_page_size && !contiguous) { > + void* obj = mapped_malloc_large(size, offset); > + trace_memory_malloc_large(obj, requested_size, size, alignment); > + return obj; > + } > + > while (true) { > WITH_LOCK(free_page_ranges_lock) { > reclaimer_thread.wait_for_minimum_memory(); > @@ -842,7 +858,7 @@ static void* malloc_large(size_t size, size_t > alignment, bool block = true) > if (alignment > page_size) { > ret_header = free_page_ranges.alloc_aligned(size, > page_size, alignment); > } else { > - ret_header = free_page_ranges.alloc(size); > + ret_header = free_page_ranges.alloc(size, contiguous); > } > if (ret_header) { > on_alloc(size); > @@ -850,6 +866,10 @@ static void* malloc_large(size_t size, size_t > alignment, bool block = true) > obj += offset; > trace_memory_malloc_large(obj, requested_size, size, > alignment); > return obj; > + } else if (!contiguous) { > + // If we failed to get contiguous memory allocation and > + // the caller does not require one let us use map-based > allocation > + break; > } > if (block) > reclaimer_thread.wait_for_memory(size); > @@ -857,6 +877,10 @@ static void* malloc_large(size_t size, size_t > alignment, bool block = true) > return nullptr; > } > } > + > + void* obj = mapped_malloc_large(size, offset); > + trace_memory_malloc_large(obj, requested_size, size, alignment); > + return obj; > nipick: wouldn't it be clearer to put this code where you have the "break" above (instead of the "break"), instead of here? } > > void shrinker::deactivate_shrinker() > @@ -1072,9 +1096,11 @@ static void free_large(void* obj) > > static unsigned large_object_size(void *obj) > { > + auto original_obj = obj; > obj = align_down(obj - 1, page_size); > + size_t offset = reinterpret_cast<uint64_t>(original_obj) - > reinterpret_cast<uint64_t>(obj); > auto header = static_cast<page_range*>(obj); > - return header->size; > + return header->size - offset; > } > I wonder if just this change explains https://github.com/cloudius-systems/osv/issues/784 and we should close that issue. But don't feel an expert enough in this issue to say... > namespace page_pool { > @@ -1692,7 +1718,7 @@ static inline void* std_malloc(size_t size, size_t > alignment) > memory::alloc_page()); > trace_memory_malloc_page(ret, size, mmu::page_size, alignment); > } else { > - ret = memory::malloc_large(size, alignment); > + ret = memory::malloc_large(size, alignment, true, false); > } > memory::tracker_remember(ret, size); > return ret; > @@ -1714,6 +1740,14 @@ void* calloc(size_t nmemb, size_t size) > > static size_t object_size(void *object) > { > + if (!mmu::is_linear_mapped(object, 0)) { > + auto original_object = object; > + object = align_down(object - 1, mmu::page_size); > + size_t offset = reinterpret_cast<uint64_t>(original_object) - > reinterpret_cast<uint64_t>(object); > + size_t* ret_header = static_cast<size_t*>(object); > + return *ret_header - offset; > Can you just call large_object_size() here instead of duplicating its code? Just like you do below in the mmu::mem_area::main case? > + } > + > switch (mmu::get_mem_area(object)) { > case mmu::mem_area::main: > return memory::large_object_size(object); > @@ -1763,6 +1797,14 @@ void free(void* object) > return; > } > memory::tracker_forget(object); > + > + if (!mmu::is_linear_mapped(object, 0)) { > + object = align_down(object - 1, mmu::page_size); > + size_t* ret_header = static_cast<size_t*>(object); > + mmu::munmap(object, *ret_header); > + return; > Nitpick: would be nice to put this code in a function mapped_free_large(), and put this function next to mapped_malloc_large() which you already have - so a reader can see the two of them next to each other. + } > + > switch (mmu::get_mem_area(object)) { > case mmu::mem_area::page: > object = mmu::translate_mem_area(mmu::mem_area::page, > @@ -1972,7 +2014,7 @@ void* alloc_phys_contiguous_aligned(size_t size, > size_t align, bool block) > assert(is_power_of_two(align)); > // make use of the standard large allocator returning properly aligned > // physically contiguous memory: > - auto ret = malloc_large(size, align, block); > + auto ret = malloc_large(size, align, block, true); > assert (!(reinterpret_cast<uintptr_t>(ret) & (align - 1))); > return ret; > } > diff --git a/modules/tests/Makefile b/modules/tests/Makefile > index ce004339..10df022f 100644 > --- a/modules/tests/Makefile > +++ b/modules/tests/Makefile > @@ -129,7 +129,7 @@ tests := tst-pthread.so misc-ramdisk.so tst-vblk.so > tst-bsd-evh.so \ > tst-sigaltstack.so tst-fread.so tst-tcp-cork.so tst-tcp-v6.so \ > tst-calloc.so tst-crypt.so tst-non-fpic.so tst-small-malloc.so \ > tst-mmx-fpu.so tst-getopt.so tst-getopt-pie.so tst-non-pie.so > tst-semaphore.so \ > - tst-elf-init.so > + tst-elf-init.so tst-realloc.so > # libstatic-thread-variable.so tst-static-thread-variable.so \ > > tests += testrunner.so > diff --git a/tests/tst-realloc.cc b/tests/tst-realloc.cc > new file mode 100644 > index 00000000..49edfb7a > --- /dev/null > +++ b/tests/tst-realloc.cc > @@ -0,0 +1,94 @@ > +/* > +* Copyright (C) 2020 Waldemar Kozaczuk > +* > +* This work is open source software, licensed under the terms of the > +* BSD license as described in the LICENSE file in the top-level directory. > +*/ > + > +#include <stdlib.h> > +#include <string.h> > +#include <cassert> > +#include <iostream> > + > +extern "C" size_t malloc_usable_size (void *ptr); > + > +static void test_realloc(size_t original_size, size_t new_size) > +{ > + char data[11] = "0123456789"; > + > + void *original_buf = malloc(original_size); > + assert(original_buf); > + > + char *buf = static_cast<char*>(original_buf); > + for (size_t i = 0; i < original_size; i++) { > + buf[i] = data[i % 10]; > + } > + > + void *new_buf = realloc(original_buf, new_size); > + assert(new_buf); > + > + auto expected_same_data_len = std::min(original_size, new_size); > + buf = static_cast<char*>(new_buf); > + for (size_t i = 0; i < expected_same_data_len; i++) { > + assert(buf[i] == data[i % 10]); > + } > + > + free(new_buf); > + > + std::cerr << "PASSED realloc() for original_size: " << original_size > << ", new_size: " << new_size << std::endl; > +} > + > +static void test_usable_size(size_t size, size_t expected_usable_size) > +{ > + void* ptr = malloc(size); > + assert(expected_usable_size == malloc_usable_size(ptr)); > + free(ptr); > + > + std::cerr << "PASSED malloc_usable_size() for size: " << size << > std::endl; > +} > + > +int main() > +{ > + test_realloc(1,2); > + test_realloc(2,1); > + > + test_realloc(4,7); > + test_realloc(7,4); > + > + test_realloc(63,128); > + test_realloc(128,63); > + > + test_realloc(4000,5000); > + test_realloc(5000,4000); > + > + test_realloc(4096,4096); > + > + test_realloc(0x100000,0x100000); > + test_realloc(0x100000,0x100900); > + test_realloc(0x100900,0x100000); > + > + test_realloc(0x200000,0x200000); > + test_realloc(0x200000,0x300900); > + test_realloc(0x300900,0x200000); > + > + test_realloc(0x600900,0x600000); > + test_realloc(0x400000,0x600000); > + test_realloc(0x600000,0x400900); > + > + void *buf = realloc(nullptr, 0); > + assert(buf); > + free(buf); > + > + buf = malloc(16); > + assert(!realloc(buf, 0)); > + > + test_usable_size(1, 8); > + test_usable_size(8, 8); > + test_usable_size(67, 128); > + test_usable_size(0x4010, 0x4FC0); > + test_usable_size(0x100000, 0x100FC0); > + test_usable_size(0x200000, 0x200FC0); > + > + std::cerr << "PASSED\n"; > + return 0; > +} > \ No newline at end of file > -- > 2.20.1 > > -- > You received this message because you are subscribed to the Google Groups > "OSv Development" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/osv-dev/20200326183626.12013-1-jwkozaczuk%40gmail.com > . > -- You received this message because you are subscribed to the Google Groups "OSv Development" group. 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