From 16ef25b5eda3a9fc51ecea309d2cb6b0508b009b Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fl.fischer@fau.de>
Date: Sun, 11 Aug 2019 16:53:06 +0200
Subject: improve bumpptr_alloc

Return always 16 Byte aligned blocks and mmap the whole available
memory reported by free -t per thread.
---
 src/Makefile        | 14 +++++++++-----
 src/bumpptr_alloc.c | 15 +++++++++++++--
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/src/Makefile b/src/Makefile
index 9858cdf..47d0dd4 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -4,23 +4,27 @@ CC ?= gcc
 
 WARNFLAGS ?= -Wall -Wextra
 COMMONFLAGS ?= -fno-builtin -fPIC -DPIC -pthread
-OPTFLAGS ?= -O3 -DNDEBUG
+OPTFLAGS ?= -O0 -g
 
 CFLAGS ?= $(OPTFLAGS) $(WARNFLAGS) $(COMMONFLAGS)
 
 LDFLAGS ?= -pthread -static-libgcc
 
+MEMSIZE_KB=$(shell free -t | tail -1 | tr -s ' ' | cut -d ' ' -f 2)
+MEMSIZE=$(shell echo $(MEMSIZE_KB)"* 1024" | bc)
+
 .PHONY: all clean
 
 all: $(OBJDIR)/print_status_on_exit.so $(OBJDIR)/allocators/bumpptr_alloc.so
 
-$(OBJDIR)/allocators/bumpptr_alloc.so: bumpptr_alloc.c | $(OBJDIR)/allocators
+$(OBJDIR)/allocators/bumpptr_alloc.so: bumpptr_alloc.c Makefile | $(OBJDIR)/allocators
 	@echo "Compiling $@...";
-	$(CC) $(LDFLAGS) -shared $(CFLAGS) -o $@ $<
+	$(CC) $(LDFLAGS) -shared -DMEMSIZE=$(MEMSIZE) $(CFLAGS) -o $@ $<
+	# $(CC) $(LDFLAGS) -shared $(CFLAGS) -o $@ $<
 
-$(OBJDIR)/print_status_on_exit.so: print_status_on_exit.c | $(OBJDIR)
+$(OBJDIR)/print_status_on_exit.so: print_status_on_exit.c Makefile | $(OBJDIR)
 	@echo "Compiling $@...";
-	$(CC) $(LDFLAGS) -shared -O2 $(CFLAGS) -o $@ $<
+	$(CC) $(LDFLAGS) -shared $(CFLAGS) -o $@ $<
 
 $(OBJDIR)/allocators:
 	mkdir -p $@
diff --git a/src/bumpptr_alloc.c b/src/bumpptr_alloc.c
index 2690809..576dc40 100644
--- a/src/bumpptr_alloc.c
+++ b/src/bumpptr_alloc.c
@@ -6,7 +6,11 @@
 #include <string.h> /* memset */
 #include <sys/mman.h> /* memset */
 
+#define MIN_ALIGNMENT 16
+
+#ifndef MEMSIZE
 #define MEMSIZE 1024*4*1024*1024l
+#endif
 
 #ifdef __cplusplus
 extern "C" {
@@ -27,6 +31,12 @@ void* malloc(size_t size) {
 		ptr = (uintptr_t)mem_start;
 	}
 
+	// align ptr;
+	if (ptr % MIN_ALIGNMENT != 0) {
+		size_t mask = MIN_ALIGNMENT -1;
+		ptr = (ptr + mask) & ~mask;
+	}
+
 	void* ret = (void*)ptr;
 	ptr += size;
 	return ret;
@@ -49,8 +59,9 @@ void* realloc(void* ptr, size_t size) {
 }
 
 void* memalign(size_t alignment, size_t size) {
-	// bump ptr to alignment and malloc
-	ptr = (ptr + (alignment - 1)) & -alignment;
+	// align ptr to alignment and malloc
+	size_t mask = alignment - 1;
+	ptr = (ptr + mask) & ~mask;
 	return malloc(size);
 }
 
-- 
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