Messages in this thread | | | From | Michael Rubin <> | Date | Fri, 20 Aug 2010 01:19:33 -0700 | Subject | Re: [PATCH 1/3] mm: helper functions for dirty and writeback accounting |
| |
On Thu, Aug 19, 2010 at 7:34 PM, Wu Fengguang <fengguang.wu@intel.com> wrote: > On Thu, Aug 19, 2010 at 01:57:25PM -0700, Michael Rubin wrote: >> Exporting account_pages_dirty and adding a symmetric routine >> account_pages_writeback. > > s/account_pages_writeback/account_page_writeback/
Got it. thanks.
> I'd recommend to separate the changes into two patches. > It's actually a bug fix to export account_pages_dirty() for ceph, > which should be a good candidate for 2.6.36.
Good idea.
>> This allows code outside of the mm core to safely manipulate page state >> and not worry about the other accounting. Not using these routines means >> that some code will lose track of the accounting and we get bugs. This >> has happened once already. >> >> Signed-off-by: Michael Rubin <mrubin@google.com> >> --- >> fs/ceph/addr.c | 8 ++------ >> fs/nilfs2/segment.c | 2 +- >> include/linux/mm.h | 1 + >> mm/page-writeback.c | 15 +++++++++++++++ >> 4 files changed, 19 insertions(+), 7 deletions(-) >> >> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c >> index d9c60b8..359aa3a 100644 >> --- a/fs/ceph/addr.c >> +++ b/fs/ceph/addr.c >> @@ -106,12 +106,8 @@ static int ceph_set_page_dirty(struct page *page) >> if (page->mapping) { /* Race with truncate? */ >> WARN_ON_ONCE(!PageUptodate(page)); >> >> - if (mapping_cap_account_dirty(mapping)) { >> - __inc_zone_page_state(page, NR_FILE_DIRTY); >> - __inc_bdi_stat(mapping->backing_dev_info, >> - BDI_RECLAIMABLE); >> - task_io_account_write(PAGE_CACHE_SIZE); >> - } >> + if (mapping_cap_account_dirty(mapping)) > > That 'if' is not necessary. account_page_dirtied() already has one. > The extra 'if' is not an optimization either, because the ceph fs is > not likely to have un-accountable mappings.
Sweet. Thanks. > >> + account_page_dirtied(page, page->mapping); >> radix_tree_tag_set(&mapping->page_tree, >> page_index(page), PAGECACHE_TAG_DIRTY); >> >> diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c >> index c920164..967ed7d 100644 >> --- a/fs/nilfs2/segment.c >> +++ b/fs/nilfs2/segment.c >> @@ -1599,7 +1599,7 @@ nilfs_copy_replace_page_buffers(struct page *page, struct list_head *out) >> kunmap_atomic(kaddr, KM_USER0); >> >> if (!TestSetPageWriteback(clone_page)) >> - inc_zone_page_state(clone_page, NR_WRITEBACK); >> + account_page_writeback(clone_page, page_mapping(clone_page)); >> unlock_page(clone_page); >> >> return 0; >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index a2b4804..b138392 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -855,6 +855,7 @@ int __set_page_dirty_no_writeback(struct page *page); >> int redirty_page_for_writepage(struct writeback_control *wbc, >> struct page *page); >> void account_page_dirtied(struct page *page, struct address_space *mapping); >> +void account_page_writeback(struct page *page, struct address_space *mapping); >> int set_page_dirty(struct page *page); >> int set_page_dirty_lock(struct page *page); >> int clear_page_dirty_for_io(struct page *page); >> diff --git a/mm/page-writeback.c b/mm/page-writeback.c >> index 37498ef..b8e7b3b 100644 >> --- a/mm/page-writeback.c >> +++ b/mm/page-writeback.c >> @@ -1096,6 +1096,21 @@ void account_page_dirtied(struct page *page, struct address_space *mapping) >> task_io_account_write(PAGE_CACHE_SIZE); >> } >> } >> +EXPORT_SYMBOL(account_page_dirtied); >> + >> +/* >> + * Helper function for set_page_writeback family. >> + * NOTE: Unlike account_page_dirtied this does not rely on being atomic >> + * wrt interrupts. >> + */ >> + >> +void account_page_writeback(struct page *page, struct address_space *mapping) >> +{ >> + if (mapping_cap_account_dirty(mapping)) > > The 'if' test and *mapping parameter looks unnecessary at least for > now. The only place a mapping has BDI_CAP_NO_ACCT_WB but not > BDI_CAP_NO_WRITEBACK is fuse, which does its own accounting.
Cool. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |