From: Waldemar Kozaczuk <jwkozac...@gmail.com>
Committer: Nadav Har'El <n...@scylladb.com>
Branch: master
Fix bug in arch_setup_free_memory
The commit 97fe8aa3d2d8f2c938fcaa379c44ae5a80dfbf33 adjusted logic
in arch_setup_free_memory() to improve memory utilization
by making OSv use memory below kernel (<= 2MB).
Ironically the new logic introduced new bug which led to much bigger
waste of memory. Specifically it did not take into account
the case of memory region starting below 2MB and ending
above 1GB at the same time and make it skip the part above 1GB altogether.
This patch fixes this bug and makes issue reported below go away.
Fixes #1048
Signed-off-by: Waldemar Kozaczuk <jwkozac...@gmail.com>
Message-Id: <20190821025311.8383-1-jwkozac...@gmail.com>
---
diff --git a/arch/x64/arch-setup.cc b/arch/x64/arch-setup.cc
--- a/arch/x64/arch-setup.cc
+++ b/arch/x64/arch-setup.cc
@@ -175,11 +175,15 @@ void arch_setup_free_memory()
//
// Free the memory below elf_phys_start which we could not before
if (ent.addr < (u64)elf_phys_start) {
+ auto ent_below_kernel = ent;
if (ent.addr + ent.size >= (u64)elf_phys_start) {
- ent = truncate_above(ent, (u64) elf_phys_start);
+ ent_below_kernel = truncate_above(ent, (u64)
elf_phys_start);
+ }
+ mmu::free_initial_memory_range(ent_below_kernel.addr,
ent_below_kernel.size);
+ // If there is nothing left below elf_phys_start return
+ if (ent.addr + ent.size <= (u64)elf_phys_start) {
+ return;
}
- mmu::free_initial_memory_range(ent.addr, ent.size);
- return;
}
//
// Ignore memory already freed above
@@ -331,4 +335,4 @@ void reset_bootchart(osv_multiboot_info_type* mb_info)
mb_info->tsc_uncompress_done_hi = now_high;
mb_info->tsc_uncompress_done = now_low;
-}
\ No newline at end of file
+}
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