• Baoquan He's avatar
    mm: memmap_init: iterate over memblock regions rather that check each PFN · 73a6e474
    Baoquan He authored
    When called during boot the memmap_init_zone() function checks if each PFN
    is valid and actually belongs to the node being initialized using
    early_pfn_valid() and early_pfn_in_nid().
    
    Each such check may cost up to O(log(n)) where n is the number of memory
    banks, so for large amount of memory overall time spent in early_pfn*()
    becomes substantial.
    
    Since the information is anyway present in memblock, we can iterate over
    memblock memory regions in memmap_init() and only call memmap_init_zone()
    for PFN ranges that are know to be valid and in the appropriate node.
    
    [cai@lca.pw: fix a compilation warning from Clang]
      Link: http://lkml.kernel.org/r/CF6E407F-17DC-427C-8203-21979FB882EF@lca.pw
    [bhe@redhat.com: fix the incorrect hole in fast_isolate_freepages()]
      Link: http://lkml.kernel.org/r/8C537EB7-85EE-4DCF-943E-3CC0ED0DF56D@lca.pw
      Link: http://lkml.kernel.org/r/20200521014407.29690-1-bhe@redhat.comSigned-off-by: default avatarBaoquan He <bhe@redhat.com>
    Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Tested-by: Hoan Tran <hoan@os.amperecomputing.com>	[arm64]
    Cc: Brian Cain <bcain@codeaurora.org>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: "David S. Miller" <davem@davemloft.net>
    Cc: Geert Uytterhoeven <geert@linux-m68k.org>
    Cc: Greentime Hu <green.hu@gmail.com>
    Cc: Greg Ungerer <gerg@linux-m68k.org>
    Cc: Guan Xuetao <gxt@pku.edu.cn>
    Cc: Guo Ren <guoren@kernel.org>
    Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
    Cc: Helge Deller <deller@gmx.de>
    Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
    Cc: Jonathan Corbet <corbet@lwn.net>
    Cc: Ley Foon Tan <ley.foon.tan@intel.com>
    Cc: Mark Salter <msalter@redhat.com>
    Cc: Matt Turner <mattst88@gmail.com>
    Cc: Max Filippov <jcmvbkbc@gmail.com>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Michal Hocko <mhocko@kernel.org>
    Cc: Michal Simek <monstr@monstr.eu>
    Cc: Nick Hu <nickhu@andestech.com>
    Cc: Paul Walmsley <paul.walmsley@sifive.com>
    Cc: Richard Weinberger <richard@nod.at>
    Cc: Rich Felker <dalias@libc.org>
    Cc: Russell King <linux@armlinux.org.uk>
    Cc: Stafford Horne <shorne@gmail.com>
    Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
    Cc: Tony Luck <tony.luck@intel.com>
    Cc: Vineet Gupta <vgupta@synopsys.com>
    Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
    Cc: Qian Cai <cai@lca.pw>
    Link: http://lkml.kernel.org/r/20200412194859.12663-16-rppt@kernel.orgSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    73a6e474
compaction.c 75.2 KB