1. 14 Dec, 2002 21 commits
    • Andrew Morton's avatar
      [PATCH] fs-writeback rework. · 20b96b52
      Andrew Morton authored
      I've revisited all the superblock->inode->page writeback paths.  There
      were several silly things in there, and things were not as clear as they
      could be.
      
      scenario 1: create and dirty a MAP_SHARED segment over a sparse file,
      then exit.
      
        All the memory turns into dirty pagecache, but the kupdate function
        only writes it out at a trickle - 4 megabytes every thirty seconds.
        We should sync it all within 30 seconds.
      
        What's happening is that when writeback tries to write those pages,
        the filesystem needs to instantiate new blocks for them (they're over
        holes).  The filesystem runs mark_inode_dirty() within the writeback
        function.
      
        This redirtying of the inode while we're writing it out triggers
        some livelock avoidance code in __sync_single_inode().  That function
        says "ah, someone redirtied the file while I was writing it.  Let's
        move the file to the new end of the superblock dirty list and write
        it out later." Problem is, writeback dirtied the inode itself.
      
        (It is rather silly that mark_inode_dirty() sets I_DIRTY_PAGES when
        clearly no pages have been dirtied.  Fixing that up would be a
        largish work, so work around it here).
      
        So this patch just removes the livelock avoidance from
        __sync_single_inode().  It is no longer needed anyway - writeback
        livelock is now avoided (in all writeback paths) by writing a finite
        number of pages.
      
      scenario 2: an application is continuously dirtying a 200 megabyte
      file, and your disk has a bandwidth of less than 40 megabytes/sec.
      
        What happens is that once 30 seconds passes, pdflush starts writing
        out the file.  And because that writeout will take more than five
        seconds (a `kupdate' interval), pdflush just keeps writing it out
        forever - continuous I/O.
      
        What we _want_ to happen is that the 200 megabytes gets written,
        and then IO stops for thirty seconds (minus the writeout period).  So
        the file is fully synced every thirty seconds.
      
      The patch solves this by using mapping->io_pages more intelligently.
      When the time comes to write the file out, move all the dirty pages
      onto io_pages.  That is a "batch of pages for this kupdate round".
      When io_pages is empty, we know we're done.
      
      The address_space_operations.writepages() API is changed!  It now only
      needs to write the pages which the caller placed on mapping->io_pages.
      
      This conceptually cleans things up a bit, by more clearly defining the
      role of ->io_pages, and the motion between the various mapping lists.
      
      The treatment of sb->s_dirty and sb->s_io is now conceptually identical
      to mapping->dirty_pages and mapping->io_pages: move the items-to-be
      written onto ->s_io/io_pages, alk walk that list.  As inodes (or pages)
      are written, move them over to the clean/locked/dirty lists.
      
      Oh, scenario 3: start an app whcih continuously overwrites a 5 meg
      file.  Wait five seconds, start another, wait 5 seconds, start another.
       What we _should_ see is three 5-meg writes, five seconds apart, every
      thirty seconds.  That did all sorts of odd things.  It now does the
      right thing.
      20b96b52
    • Andrew Morton's avatar
      [PATCH] hugetlb fixes · 21c2baef
      Andrew Morton authored
      From Rohit
      
      1) hugetlbfs_zero_setup returns ENOMEM in case the request size can
         not be easily handleed.
      
      2) Preference is given to LOW_MEM while freeing the pages from
         hugetlbpage free list.
      21c2baef
    • Andrew Morton's avatar
      [PATCH] vm accounting fixes and addition · c720c50a
      Andrew Morton authored
      - /proc/vmstat:pageoutrun and /proc/vmstat:allocstall are always
        identical.  Rework this so that
      
        - "allocstall" is the number of times a page allocator ran diect reclaim
      
        - "pageoutrun" is the number of times kswapd ran page reclaim
      
      - Add a new stat: "pgrotated".  The number of pages which were
        rotated to the tail of the LRU for immediate reclaim by
        rotate_reclaimable_page().
      
      - Document things a bit.
      c720c50a
    • Andrew Morton's avatar
      [PATCH] copy_user checks in filldir() · 54cbdcfd
      Andrew Morton authored
      Check for usercopy faults in filldir().
      54cbdcfd
    • Andrew Morton's avatar
      [PATCH] implement ext3_sync_fs · 012af46c
      Andrew Morton authored
      ext3_sync_fs will start a commit and will wait on that commit.  This
      means that on its return, all journalled file data has been dirtied and
      exposed to sync_inodes_sb().  Which is sufficient to fix the umount
      data loss problem.
      012af46c
    • Andrew Morton's avatar
      [PATCH] Add a sync_fs super_block operation · 75f19a40
      Andrew Morton authored
      This is infrastructure for fixing the journalled-data ext3 unmount data
      loss problem. It was sent for comment to linux-fsdevel a week ago; there
      was none.
      
      Add a `sync_fs' superblock operation whose mandate is to perform
      filesystem-specific operations to ensure a successful sync.
      
      It is called in two places:
      
      1: fsync_super() - for umount.
      
      2: sys_sync() - for global sync.
      
      In the sys_sync() case we call all the ->write_super() methods first.
      write_super() is an async flushing operation.  It should not block.
      
      After that, we call all the ->sync_fs functions.  This is independent
      of the state of s_dirt!  That was all confused up before, and in this
      patch ->write_super() and ->sync_fs() are quite separate.
      
      With ext3 as an example, the initial ->write_super() will start a
      transaction, but will not wait on it.  (But only if s_dirt was set!)
      
      The first ->sync_fs() call will get the IO underway.
      
      The second ->sync_fs() call will wait on the IO.
      
      And we really do need to be this elaborate, because all the testing of
      s_dirt in there makes ->write_super() an unreliable way of detecting
      when the VFS is trying to sync the filesystem.
      75f19a40
    • Andrew Morton's avatar
      [PATCH] handle overflows in radix_tree_gang_lookup() · 7404e32c
      Andrew Morton authored
      Fix a radix-tree bug spotted by Vladimir Saveliev <vs@namesys.com>.
      
      Each step in the radix tree spans six address bits.  So a height=6 tree
      spans 36-bits worth of nodes.
      
      On 32-bit machines radix_tree_gang_lookup() doesn't handle this right -
      at the 12TB mark it wraps back to zero, and returns pages at quite
      wrong indices.
      
      The patch fixes all that up, and tidies a couple of things.
      
      A user-space test harness was developed so that the code can be sanely
      tested.  It is at
      
      	http://www.zip.com.au/~akpm/linux/patches/stuff/rtth.tar.gz
      7404e32c
    • Andrew Morton's avatar
      [PATCH] make sure all PMDs are allocated under PAE mode · 2134c937
      Andrew Morton authored
      Patch from Martin Bligh and Dave Hansen
      
      If a PAE machine has 1G of memory and you set PAGE_OFFSET to 2G, the
      kernel will only instantiate a PMD to cover the 2G-3G region.  But
      another PMD is needed for the 3G-4G region for the APIC and possibly an
      extended vmalloc region.
      
      So the patch changes the code to instantiate PMDs out to the end of
      physical memory.
      
      It's a no-op for PAGE_OFFSET=3G, and _could_ be part of the
      CONFIG_PAGE_OFFSET patch.  But it seems a reasonable generalisation
      anyway.
      2134c937
    • Andrew Morton's avatar
      [PATCH] show_free_areas extensions · b7fdef78
      Andrew Morton authored
      Ancient patch From Bill Irwin
      
      The patch is intended to show improved information about where the
      memory went during OOM-killing events.
      
      - when the OOM killer fails and the system panics, calls
        show_free_areas()
      
      - reorganize show_free_areas() to use for_each_zone()
      
      - add per-cpu stats to show_free_areas()
      
      - tags output from show_free_areas() with node and zone information
      b7fdef78
    • Andrew Morton's avatar
      [PATCH] Remove fail_writepage, redux · 3e9afe4c
      Andrew Morton authored
      fail_writepage() does not work.  Its activate_page() call cannot
      activate the page because it is not on the LRU.
      
      So perform that function (more efficiently) in the VM.  Remove
      fail_writepage() and, if the filesystem does not implement
      ->writepage() then activate the page from shrink_list().
      
      A special case is tmpfs, which does have a writepage, but which
      sometimes wants to activate the pages anyway.  The most important case
      is when there is no swap online and we don't want to keep all those
      pages on the inactive list.  So just as a tmpfs special-case, allow
      writepage() to return WRITEPAGE_ACTIVATE, and handle that in the VM.
      
      Also, the whole idea of allowing ->writepage() to return -EAGAIN, and
      handling that in the caller has been reverted.  If a writepage()
      implementation wants to back out and not write the page, it must
      redirty the page, unlock it and return zero.  (This is Hugh's preferred
      way).
      
      And remove the now-unneeded shmem_writepages() - shmem inodes are
      marked as `memory backed' so it will not be called.
      
      And remove the test for non-null ->writepage() in generic_file_mmap().
      Memory-backed files _are_ mmappable, and they do not have a
      writepage().  It just isn't called.
      
      So the locking rules for writepage() are unchanged.  They are:
      
      - Called with the page locked
      - Returns with the page unlocked
      - Must redirty the page itself if it wasn't all written.
      
      But there is a new, special, hidden, undocumented, secret hack for
      tmpfs: writepage may return WRITEPAGE_ACTIVATE to tell the VM to move
      the page to the active list.  The page must be kept locked in this one
      case.
      3e9afe4c
    • Andrew Morton's avatar
      [PATCH] skip memory-backed filesystems in writeback · 660282aa
      Andrew Morton authored
      There's nopoint in walking through a lot of tmpfs or ramdisk pages when
      we're trying to clean memory.  So if a memory-backed inode is
      discovered during writeback, skip the entire superblock.
      660282aa
    • Andrew Morton's avatar
      [PATCH] semtimedop - semop() with a timeout · f99a1a55
      Andrew Morton authored
      Patch from Mark Fasheh <mark.fasheh@oracle.com> (plus a few cleanups
      and a speedup from yours truly)
      
      Adds the semtimedop() function - semop with a timeout.  Solaris has
      this.  It's apparently worth a couple of percent to Oracle throughput
      and given the simplicity, that is sufficient benefit for inclusion IMO.
      
      This patch hooks up semtimedop() only for ia64 and ia32.
      f99a1a55
    • Andrew Morton's avatar
      [PATCH] Fix rmap locking for CONFIG_SWAP=n · c7d7f43a
      Andrew Morton authored
      The pte_chain_unlock() needs to be outside the ifdef.
      c7d7f43a
    • Andrew Morton's avatar
      [PATCH] speed up read_zero() for !CONFIG_MMU · 849696bb
      Andrew Morton authored
      The read_zero() implementation for !CONFIG_MMU was very inefficient.
      This sped-up version has been tested and acked by Greg Ungerer.
      849696bb
    • Andrew Morton's avatar
      [PATCH] create /proc/kmsg, remove sys_syslog()-based · 48a789a9
      Andrew Morton authored
      Back out the sys_syslog()-based printk-from-userspace and replace
      it with Ben's /proc/kmsg version.
      
      Requires a `mknod /dev/kmsg c 1 11'.
      48a789a9
    • Andrew Morton's avatar
      [PATCH] deprecate use of bdflush() · 2f268ee8
      Andrew Morton authored
      Patch from Robert Love <rml@tech9.net>
      
      We can never get rid of it if we do not deprecate it - so do so and
      print a stern warning to those who still run bdflush daemons.
      2f268ee8
    • Andrew Morton's avatar
      [PATCH] Avoid recursion in the page allocator · 2a6c8678
      Andrew Morton authored
      The PF_MEMALLOC handling got broken somewhere, and it is now possible
      for a PF_MEMALLOC process to reenter page reclaim.
      
      Change it to fail the allocation if we're PF_MEMALLOC and there are
      zero pages free.
      2a6c8678
    • François Romieu's avatar
      [PATCH] missing piece of Iphase atm driver update · ee842908
      François Romieu authored
      This removes calls to function which disappeared during last Iphase
      driver update.  Since this update, Iphase driver has been using plain
      modern pci style init.
      
      Problem wasn't noticed until Adrian Bunk tried to build non-modular kernel
      (I only tested the modularized driver). Everybody else seemed happy :o)
      ee842908
    • James Simmons's avatar
      [PATCH] VT scrolling fix · 6faa9cfc
      James Simmons authored
      scrup is using memcpy even when the memory areas src, dest overlap.  The
      key is to use memmove which handles overlapping memory gracefully.
      6faa9cfc
    • Linus Torvalds's avatar
      Merge bk://thebsh.namesys.com/bk/reiser3-linux-2.5-fixes · 36db78e3
      Linus Torvalds authored
      into home.transmeta.com:/home/torvalds/v2.5/linux
      36db78e3
    • Anton Blanchard's avatar
      [PATCH] 2.5 fix for > 25 disks · 49b0c2a3
      Anton Blanchard authored
      2.5 currently tries to register disk sda twice. Not nice and now we use
      sysfs to do name to dev_t mapping, I couldnt mount my root filesystem.
      49b0c2a3
  2. 13 Dec, 2002 13 commits
  3. 12 Dec, 2002 6 commits