1. 16 9月, 2008 1 次提交
  2. 18 8月, 2008 1 次提交
  3. 04 8月, 2008 1 次提交
  4. 25 7月, 2008 1 次提交
  5. 14 2月, 2008 1 次提交
  6. 06 2月, 2008 1 次提交
    • D
      timerfd: new timerfd API · 4d672e7a
      Davide Libenzi 提交于
      This is the new timerfd API as it is implemented by the following patch:
      
      int timerfd_create(int clockid, int flags);
      int timerfd_settime(int ufd, int flags,
      		    const struct itimerspec *utmr,
      		    struct itimerspec *otmr);
      int timerfd_gettime(int ufd, struct itimerspec *otmr);
      
      The timerfd_create() API creates an un-programmed timerfd fd.  The "clockid"
      parameter can be either CLOCK_MONOTONIC or CLOCK_REALTIME.
      
      The timerfd_settime() API give new settings by the timerfd fd, by optionally
      retrieving the previous expiration time (in case the "otmr" parameter is not
      NULL).
      
      The time value specified in "utmr" is absolute, if the TFD_TIMER_ABSTIME bit
      is set in the "flags" parameter.  Otherwise it's a relative time.
      
      The timerfd_gettime() API returns the next expiration time of the timer, or
      {0, 0} if the timerfd has not been set yet.
      
      Like the previous timerfd API implementation, read(2) and poll(2) are
      supported (with the same interface).  Here's a simple test program I used to
      exercise the new timerfd APIs:
      
      http://www.xmailserver.org/timerfd-test2.c
      
      [akpm@linux-foundation.org: coding-style cleanups]
      [akpm@linux-foundation.org: fix ia64 build]
      [akpm@linux-foundation.org: fix m68k build]
      [akpm@linux-foundation.org: fix mips build]
      [akpm@linux-foundation.org: fix alpha, arm, blackfin, cris, m68k, s390, sparc and sparc64 builds]
      [heiko.carstens@de.ibm.com: fix s390]
      [akpm@linux-foundation.org: fix powerpc build]
      [akpm@linux-foundation.org: fix sparc64 more]
      Signed-off-by: NDavide Libenzi <davidel@xmailserver.org>
      Cc: Michael Kerrisk <mtk-manpages@gmx.net>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Davide Libenzi <davidel@xmailserver.org>
      Cc: Michael Kerrisk <mtk-manpages@gmx.net>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Davide Libenzi <davidel@xmailserver.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4d672e7a
  7. 24 1月, 2008 1 次提交
    • P
      [POWERPC] Provide a way to protect 4k subpages when using 64k pages · fa28237c
      Paul Mackerras 提交于
      Using 64k pages on 64-bit PowerPC systems makes life difficult for
      emulators that are trying to emulate an ISA, such as x86, which use a
      smaller page size, since the emulator can no longer use the MMU and
      the normal system calls for controlling page protections.  Of course,
      the emulator can emulate the MMU by checking and possibly remapping
      the address for each memory access in software, but that is pretty
      slow.
      
      This provides a facility for such programs to control the access
      permissions on individual 4k sub-pages of 64k pages.  The idea is
      that the emulator supplies an array of protection masks to apply to a
      specified range of virtual addresses.  These masks are applied at the
      level where hardware PTEs are inserted into the hardware page table
      based on the Linux PTEs, so the Linux PTEs are not affected.  Note
      that this new mechanism does not allow any access that would otherwise
      be prohibited; it can only prohibit accesses that would otherwise be
      allowed.  This new facility is only available on 64-bit PowerPC and
      only when the kernel is configured for 64k pages.
      
      The masks are supplied using a new subpage_prot system call, which
      takes a starting virtual address and length, and a pointer to an array
      of protection masks in memory.  The array has a 32-bit word per 64k
      page to be protected; each 32-bit word consists of 16 2-bit fields,
      for which 0 allows any access (that is otherwise allowed), 1 prevents
      write accesses, and 2 or 3 prevent any access.
      
      Implicit in this is that the regions of the address space that are
      protected are switched to use 4k hardware pages rather than 64k
      hardware pages (on machines with hardware 64k page support).  In fact
      the whole process is switched to use 4k hardware pages when the
      subpage_prot system call is used, but this could be improved in future
      to switch only the affected segments.
      
      The subpage protection bits are stored in a 3 level tree akin to the
      page table tree.  The top level of this tree is stored in a structure
      that is appended to the top level of the page table tree, i.e., the
      pgd array.  Since it will often only be 32-bit addresses (below 4GB)
      that are protected, the pointers to the first four bottom level pages
      are also stored in this structure (each bottom level page contains the
      protection bits for 1GB of address space), so the protection bits for
      addresses below 4GB can be accessed with one fewer loads than those
      for higher addresses.
      Signed-off-by: NPaul Mackerras <paulus@samba.org>
      fa28237c
  8. 08 11月, 2007 1 次提交
  9. 18 7月, 2007 1 次提交
    • A
      sys_fallocate() implementation on i386, x86_64 and powerpc · 97ac7350
      Amit Arora 提交于
      fallocate() is a new system call being proposed here which will allow
      applications to preallocate space to any file(s) in a file system.
      Each file system implementation that wants to use this feature will need
      to support an inode operation called ->fallocate().
      Applications can use this feature to avoid fragmentation to certain
      level and thus get faster access speed. With preallocation, applications
      also get a guarantee of space for particular file(s) - even if later the
      the system becomes full.
      
      Currently, glibc provides an interface called posix_fallocate() which
      can be used for similar cause. Though this has the advantage of working
      on all file systems, but it is quite slow (since it writes zeroes to
      each block that has to be preallocated). Without a doubt, file systems
      can do this more efficiently within the kernel, by implementing
      the proposed fallocate() system call. It is expected that
      posix_fallocate() will be modified to call this new system call first
      and incase the kernel/filesystem does not implement it, it should fall
      back to the current implementation of writing zeroes to the new blocks.
      ToDos:
      1. Implementation on other architectures (other than i386, x86_64,
         and ppc). Patches for s390(x) and ia64 are already available from
         previous posts, but it was decided that they should be added later
         once fallocate is in the mainline. Hence not including those patches
         in this take.
      2. Changes to glibc,
         a) to support fallocate() system call
         b) to make posix_fallocate() and posix_fallocate64() call fallocate()
      Signed-off-by: NAmit Arora <aarora@in.ibm.com>
      97ac7350
  10. 29 6月, 2007 1 次提交
    • D
      Introduce fixed sys_sync_file_range2() syscall, implement on PowerPC and ARM · edd5cd4a
      David Woodhouse 提交于
      Not all the world is an i386.  Many architectures need 64-bit arguments to be
      aligned in suitable pairs of registers, and the original
      sys_sync_file_range(int, loff_t, loff_t, int) was therefore wasting an
      argument register for padding after the first integer.  Since we don't
      normally have more than 6 arguments for system calls, that left no room for
      the final argument on some architectures.
      
      Fix this by introducing sys_sync_file_range2(int, int, loff_t, loff_t) which
      all fits nicely.  In fact, ARM already had that, but called it
      sys_arm_sync_file_range.  Move it to fs/sync.c and rename it, then implement
      the needed compatibility routine.  And stop the missing syscall check from
      bitching about the absence of sys_sync_file_range() if we've implemented
      sys_sync_file_range2() instead.
      
      Tested on PPC32 and with 32-bit and 64-bit userspace on PPC64.
      Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>
      Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Paul Mackerras <paulus@samba.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      edd5cd4a
  11. 17 5月, 2007 1 次提交
  12. 10 5月, 2007 1 次提交
  13. 18 4月, 2007 1 次提交
  14. 12 3月, 2007 2 次提交
  15. 13 2月, 2007 1 次提交
  16. 16 11月, 2006 1 次提交
  17. 04 11月, 2006 1 次提交
  18. 21 6月, 2006 1 次提交