Le sunnuntaina 18. helmikuuta 2024, 18.16.36 EET James Almer a écrit : > Save for the Microsoft C Runtime library, where free() can't handle aligned > buffers, aligned_malloc() should be available and working on all supported > targets. > Also, malloc() alone may be sufficient if alignment requirement is low, so > add a check for it. > > Signed-off-by: James Almer <jamr...@gmail.com> > --- > configure | 2 -- > libavutil/mem.c | 42 ++++++------------------------------------ > 2 files changed, 6 insertions(+), 38 deletions(-) > > diff --git a/configure b/configure > index 7c45ac25c8..8fd2895ac2 100755 > --- a/configure > +++ b/configure > @@ -6450,8 +6450,6 @@ if test -n "$custom_allocator"; then > fi > > check_func_headers malloc.h _aligned_malloc && enable aligned_malloc > -check_func ${malloc_prefix}memalign && enable memalign > -check_func ${malloc_prefix}posix_memalign && enable posix_memalign > > check_func access > check_func_headers stdlib.h arc4random_buf > diff --git a/libavutil/mem.c b/libavutil/mem.c > index 36b8940a0c..a72981d1ab 100644 > --- a/libavutil/mem.c > +++ b/libavutil/mem.c > @@ -100,44 +100,14 @@ void *av_malloc(size_t size) > if (size > atomic_load_explicit(&max_alloc_size, memory_order_relaxed)) > return NULL; > > -#if HAVE_POSIX_MEMALIGN > - if (size) //OS X on SDK 10.6 has a broken posix_memalign implementation > - if (posix_memalign(&ptr, ALIGN, size)) > - ptr = NULL; > -#elif HAVE_ALIGNED_MALLOC > +#if HAVE_ALIGNED_MALLOC > ptr = _aligned_malloc(size, ALIGN); > -#elif HAVE_MEMALIGN > -#ifndef __DJGPP__ > - ptr = memalign(ALIGN, size); > -#else > - ptr = memalign(size, ALIGN); > -#endif > - /* Why 64? > - * Indeed, we should align it: > - * on 4 for 386 > - * on 16 for 486 > - * on 32 for 586, PPro - K6-III > - * on 64 for K7 (maybe for P3 too). > - * Because L1 and L2 caches are aligned on those values. > - * But I don't want to code such logic here! > - */ > - /* Why 32? > - * For AVX ASM. SSE / NEON needs only 16. > - * Why not larger? Because I did not see a difference in benchmarks ... > - */ > - /* benchmarks with P3 > - * memalign(64) + 1 3071, 3051, 3032 > - * memalign(64) + 2 3051, 3032, 3041 > - * memalign(64) + 4 2911, 2896, 2915 > - * memalign(64) + 8 2545, 2554, 2550 > - * memalign(64) + 16 2543, 2572, 2563 > - * memalign(64) + 32 2546, 2545, 2571 > - * memalign(64) + 64 2570, 2533, 2558 > - * > - * BTW, malloc seems to do 8-byte alignment by default here. > - */ > #else > - ptr = malloc(size); > + // malloc may already allocate sufficiently aligned buffers > + if (ALIGN > _Alignof(max_align_t))
If you ever try to reintroduce something like this, you would need <stdalign.h> here, and thus you should use alignof rather than _Alignof (which was already deprecated by C23 deprecated). > + ptr = aligned_malloc(size, ALIGN); > + else > + ptr = malloc(size); > #endif > if(!ptr && !size) { > size = 1; -- Rémi Denis-Courmont http://www.remlab.net/ _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".