linux/mm
KOSAKI Motohiro bd775c42ea mm: add comment why mark_page_accessed() would be better than pte_mkyoung() in follow_page()
At first look, mark_page_accessed() in follow_page() seems a bit strange.
It seems pte_mkyoung() would be better consistent with other kernel code.

However, it is intentional. The commit log said:

    ------------------------------------------------
    commit 9e45f61d69be9024a2e6bef3831fb04d90fac7a8
    Author: akpm <akpm>
    Date:   Fri Aug 15 07:24:59 2003 +0000

    [PATCH] Use mark_page_accessed() in follow_page()

    Touching a page via follow_page() counts as a reference so we should be
    either setting the referenced bit in the pte or running mark_page_accessed().

    Altering the pte is tricky because we haven't implemented an atomic
    pte_mkyoung().  And mark_page_accessed() is better anyway because it has more
    aging state: it can move the page onto the active list.

    BKrev: 3f3c8acbplT8FbwBVGtth7QmnqWkIw
    ------------------------------------------------

The atomic issue is still true nowadays. adding comment help to understand
code intention and it would be better.

[akpm@linux-foundation.org: clarify text]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:12 -07:00
..
allocpercpu.c cpumask: use new cpumask_ functions in core code. 2009-03-30 22:05:16 +10:30
backing-dev.c Move the default_backing_dev_info out of readahead.c and into backing-dev.c 2009-03-26 11:01:33 +01:00
bootmem.c bootmem, x86: further fixes for arch-specific bootmem wrapping 2009-03-01 16:06:56 +09:00
bounce.c bounce: don't rely on a zeroed bio_vec list 2008-12-29 08:29:52 +01:00
dmapool.c dmapool: enable debugging for CONFIG_SLUB_DEBUG_ON too 2008-04-28 08:58:20 -07:00
fadvise.c [CVE-2009-0029] System call wrapper special cases 2009-01-14 14:15:18 +01:00
failslab.c SLUB: failslab support 2008-12-29 11:27:46 +02:00
filemap_xip.c x86, mm: dont use non-temporal stores in pagecache accesses 2009-03-02 11:06:49 +01:00
filemap.c x86, mm: dont use non-temporal stores in pagecache accesses 2009-03-02 11:06:49 +01:00
fremap.c Do not account for the address space used by hugetlbfs using VM_ACCOUNT 2009-02-10 10:48:42 -08:00
highmem.c highmem: atomic highmem kmap page pinning 2009-03-15 21:01:21 -04:00
hugetlb.c Do not account for hugetlbfs quota at mmap() time if mapping [SHM|MAP]_NORESERVE 2009-02-11 12:38:09 -08:00
internal.h mm: make get_user_pages() interruptible 2009-01-06 15:59:08 -08:00
Kconfig Remove obsolete CONFIG_RESOURCES_64BIT 2009-01-06 15:59:14 -08:00
maccess.c kgdb: fix optional arch functions and probe_kernel_* 2008-04-17 20:05:39 +02:00
madvise.c [CVE-2009-0029] System call wrappers part 14 2009-01-14 14:15:24 +01:00
Makefile percpu: implement new dynamic percpu allocator 2009-02-20 16:29:08 +09:00
memcontrol.c memcg: NULL pointer dereference at rmdir on some NUMA systems 2009-01-29 18:04:44 -08:00
memory_hotplug.c mm: remove GFP_HIGHUSER_PAGECACHE 2009-01-06 15:59:01 -08:00
memory.c mm: add comment why mark_page_accessed() would be better than pte_mkyoung() in follow_page() 2009-04-01 08:59:12 -07:00
mempolicy.c [CVE-2009-0029] System call wrappers part 28 2009-01-14 14:15:30 +01:00
mempool.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
migrate.c migration: migrate_vmas should check "vma" 2009-02-11 14:25:34 -08:00
mincore.c [CVE-2009-0029] System call wrappers part 14 2009-01-14 14:15:24 +01:00
mlock.c Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-02-17 14:27:39 -08:00
mm_init.c mm: mminit_loglevel cannot be __meminitdata anymore 2008-08-20 15:40:30 -07:00
mmap.c Merge branch 'master' into next 2009-03-24 10:52:46 +11:00
mmu_notifier.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mmzone.c mm: mark the correct zone as full when scanning zonelists 2008-09-13 14:41:52 -07:00
mprotect.c Do not account for the address space used by hugetlbfs using VM_ACCOUNT 2009-02-10 10:48:42 -08:00
mremap.c [CVE-2009-0029] System call wrappers part 13 2009-01-14 14:15:23 +01:00
msync.c [CVE-2009-0029] System call wrappers part 13 2009-01-14 14:15:23 +01:00
nommu.c uclinux: add process name to allocation error message 2009-01-27 16:42:03 +10:00
oom_kill.c oom_kill: don't call for int_sqrt(0) 2009-04-01 08:59:11 -07:00
page_alloc.c mm: introduce for_each_populated_zone() macro 2009-04-01 08:59:11 -07:00
page_cgroup.c memcg: use __GFP_NOWARN in page cgroup allocation 2009-02-11 14:25:35 -08:00
page_io.c block: fix bad definition of BIO_RW_SYNC 2009-02-18 10:32:00 +01:00
page_isolation.c memory hotplug: fix page_zone() calculation in test_pages_isolated() 2008-11-06 15:41:19 -08:00
page-writeback.c writeback: double the dirty thresholds 2009-03-26 11:01:11 -07:00
pagewalk.c pagemap: pass mm into pagewalkers 2008-06-12 18:05:41 -07:00
pdflush.c cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALL 2009-03-30 22:05:11 +10:30
percpu.c percpu: generalize embedding first chunk setup helper 2009-03-10 16:27:48 +09:00
prio_tree.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
quicklist.c mm: size of quicklists shouldn't be proportional to the number of CPUs 2008-09-02 19:21:38 -07:00
readahead.c Move the default_backing_dev_info out of readahead.c and into backing-dev.c 2009-03-26 11:01:33 +01:00
rmap.c mm: fix mlocked page counter mismatch 2009-02-11 14:25:35 -08:00
shmem_acl.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
shmem.c Merge branch 'master' into next 2009-03-24 10:52:46 +11:00
slab.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-30 17:17:35 -07:00
slob.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-30 17:17:35 -07:00
slub.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-30 17:17:35 -07:00
sparse-vmemmap.c vmemmap: warn about page_structs with remote distance 2008-11-06 15:41:19 -08:00
sparse.c mm: mminit_validate_memmodel_limits(): remove redundant test 2009-04-01 08:59:11 -07:00
swap_state.c memcg: mem+swap controller core 2009-01-08 08:31:05 -08:00
swap.c memcg: add zone_reclaim_stat 2009-01-08 08:31:08 -08:00
swapfile.c PM/hibernate: fix "swap breaks after hibernation failures" 2009-02-21 14:17:17 -08:00
thrash.c Bug in mm/thrash.c function grab_swap_token() 2007-05-11 08:29:32 -07:00
truncate.c mmap: handle mlocked pages during map, remap, unmap 2008-10-20 08:52:31 -07:00
util.c slab: introduce kzfree() 2009-02-20 17:57:48 -08:00
vmalloc.c vmap: remove needless lock and list in vmap 2009-04-01 08:59:11 -07:00
vmscan.c vmscan: clip swap_cluster_max in shrink_all_memory() 2009-04-01 08:59:12 -07:00
vmstat.c mm: introduce for_each_populated_zone() macro 2009-04-01 08:59:11 -07:00