Re: + readahead-commentary.patch added to -mm tree

From: Coywolf Qi Hunt (coywolf_at_gmail.com)
Date: 11/03/05

  • Next message: Rusty Russell: "Re: [2.6.14-rt1] slowdown / oops." 
    Date:	Thu, 3 Nov 2005 09:58:29 +0800
To: linux-kernel@vger.kernel.org

    On 03/11/05, akpm@osdl.org <akpm@osdl.org> wrote:
    >
    > The patch titled
    >
    > readahead commentary
    >
    > has been added to the -mm tree. Its filename is
    >
    > readahead-commentary.patch
    >
    >
    > From: Andrew Morton <akpm@osdl.org>
    >
    > Add a few comments surrounding thr generic readahead API.
    >
    > Also convert some ulongs into pgoff_t: the identifier for PAGE_CACHE_SIZE
    > offsets into pagecache.
    >
    > Signed-off-by: Andrew Morton <akpm@osdl.org>
    > ---
    >
    > include/linux/mm.h | 8 ++++----
    > mm/readahead.c | 31 ++++++++++++++++++++++---------
    > 2 files changed, 26 insertions(+), 13 deletions(-)
    >
    > diff -puN mm/readahead.c~readahead-commentary mm/readahead.c
    > --- 25/mm/readahead.c~readahead-commentary 2005-11-03 08:06:16.000000000 +1100
    > +++ 25-akpm/mm/readahead.c 2005-11-03 08:16:16.000000000 +1100
    > @@ -254,7 +254,7 @@ out:
    > */
    > static int
    > __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
    > - unsigned long offset, unsigned long nr_to_read)
    > + pgoff_t offset, unsigned long nr_to_read)
    > {
    > struct inode *inode = mapping->host;
    > struct page *page;
    > @@ -274,7 +274,7 @@ __do_page_cache_readahead(struct address
    > */
    > read_lock_irq(&mapping->tree_lock);
    > for (page_idx = 0; page_idx < nr_to_read; page_idx++) {
    > - unsigned long page_offset = offset + page_idx;
    > + pgoff_t page_offset = offset + page_idx;
    >
    > if (page_offset > end_index)
    > break;
    > @@ -311,7 +311,7 @@ out:
    > * memory at once.
    > */
    > int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
    > - unsigned long offset, unsigned long nr_to_read)
    > + pgoff_t offset, unsigned long nr_to_read)
    > {
    > int ret = 0;
    >
    > @@ -368,7 +368,7 @@ static inline int check_ra_success(struc
    > * request queues.
    > */
    > int do_page_cache_readahead(struct address_space *mapping, struct file *filp,
    > - unsigned long offset, unsigned long nr_to_read)
    > + pgoff_t offset, unsigned long nr_to_read)
    > {
    > if (bdi_read_congested(mapping->backing_dev_info))
    > return -1;
    > @@ -385,7 +385,7 @@ int do_page_cache_readahead(struct addre
    > */
    > static int
    > blockable_page_cache_readahead(struct address_space *mapping, struct file *filp,
    > - unsigned long offset, unsigned long nr_to_read,
    > + pgoff_t offset, unsigned long nr_to_read,
    > struct file_ra_state *ra, int block)
    > {
    > int actual;
    > @@ -430,14 +430,27 @@ static int make_ahead_window(struct addr
    > return ret;
    > }
    >
    > -/*
    > - * page_cache_readahead is the main function. If performs the adaptive
    > +/**
    > + * page_cache_readahead - generic adaptive readahead
    > + * @mapping: address_space which holds te pagecache and I/O vectors

    typo. s/te/the/

    > + * @ra: file_ra_state which holds the readahead state
    > + * @filp: passed on to ->readpage() and ->readpages()
    > + * @offset: start offset into @mapping, in PAGE_CACHE_SIZE units
    > + * @req_size: hint: total size of the read which the caller is performing in
    > + * PAGE_CACHE_SIZE units
    > + *
    > + * page_cache_readahead() is the main function. If performs the adaptive
    > * readahead window size management and submits the readahead I/O.
    > + *
    > + * Note that @filp is purely used for passing on to the ->readpage[s]()
    > + * handler: it may refer to a different file from @mapping (so we may not use
    > + * @filp->f_mapping or @filp->f_dentry->d_inode here).
    > + * Also, @ra may not be equal to &@filp->f_ra.
    > + *
    > */
    > unsigned long
    > page_cache_readahead(struct address_space *mapping, struct file_ra_state *ra,
    > - struct file *filp, unsigned long offset,
    > - unsigned long req_size)
    > + struct file *filp, pgoff_t offset, unsigned long req_size)
    > {
    > unsigned long max, newsize;
    > int sequential; 

    --
Coywolf Qi Hunt
http://sosdg.org/~coywolf/
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