Date: Sun, 28 Jun 2009 16:42:38 -0700 From: "Sean P. Dew" <freebsd.work@gmail.com> To: freebsd-current@freebsd.org Subject: segment alignment in AMD64 Message-ID: <45d874490906281642r470089e2sc5b770f239f428e2@mail.gmail.com>
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Hi, Why is a loadable segment aligned to 1 MB on AMD64 while the pagezie is still 4K for a user application. Is there anyway to change it back to 4K, It is not making sense to me is because if my file segment is around 400K, we are wasting 1 MB of virtual address space ( granted it is not a lot for X64). I am trying to find out the reason. I am posting the readelf output of a .so. Any help is appreciated. Thanks Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align LOAD 0x000000 0x0000000000000000 0x0000000000000000 0x001428 0x001428 R E 0x100000 LOAD 0x001428 0x0000000000101428 0x0000000000101428 0x000438 0x007bd8 RW 0x100000 DYNAMIC 0x001618 0x0000000000101618 0x0000000000101618 0x000180 0x000180 RW 0x8 GNU_EH_FRAME 0x001420 0x0000000000001420 0x0000000000001420 0x000008 0x000008 R 0x4 Section to Segment mapping: Segment Sections... 00 .hash .dynsym .dynstr .gnu.version .gnu.version_r .rela.dyn .rela.plt .init .plt .text .fini .rodata .eh_frame_hdr 01 .data .eh_frame .dynamic .ctors .dtors .jcr .got .bss 02 .dynamic 03 .eh_frame_hdr
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