| Message ID | 1597306282-29927-1-git-send-email-zhaoyang.huang@unisoc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC] mm : using bdi->ra_pages instead of ra->ra_pages within readahead | expand |
On Thu, Aug 13, 2020 at 04:11:22PM +0800, Zhaoyang Huang wrote: > file->f_ra->ra_pages will remain the initialized value since it opend, which may > be NOT equal to bdi->ra_pages as the latter one is updated somehow(etc, > echo xxx > /sys/block/dm/queue/read_ahead_kb).So having readahead use > bdi->ra_pages. But now it ignores the work done by shrink_readahead_size_eio() and fadvise(POSIX_FADV_SEQUENTIAL). And you missed the use of ra_size on the previous line, miscalculating ra->start. > Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com> > --- > mm/filemap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/filemap.c b/mm/filemap.c > index d78f577..259dcfd 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2499,8 +2499,8 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf) > */ > fpin = maybe_unlock_mmap_for_io(vmf, fpin); > ra->start = max_t(long, 0, offset - ra->ra_pages / 2); > - ra->size = ra->ra_pages; > - ra->async_size = ra->ra_pages / 4; > + ra->size = inode_to_bdi(mapping->host)->ra_pages; > + ra->async_size = ra->size / 4; > ra_submit(ra, mapping, file); > return fpin; > } > -- > 1.9.1 > >
diff --git a/mm/filemap.c b/mm/filemap.c index d78f577..259dcfd 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2499,8 +2499,8 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf) */ fpin = maybe_unlock_mmap_for_io(vmf, fpin); ra->start = max_t(long, 0, offset - ra->ra_pages / 2); - ra->size = ra->ra_pages; - ra->async_size = ra->ra_pages / 4; + ra->size = inode_to_bdi(mapping->host)->ra_pages; + ra->async_size = ra->size / 4; ra_submit(ra, mapping, file); return fpin; }
file->f_ra->ra_pages will remain the initialized value since it opend, which may be NOT equal to bdi->ra_pages as the latter one is updated somehow(etc, echo xxx > /sys/block/dm/queue/read_ahead_kb).So having readahead use bdi->ra_pages. Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com> --- mm/filemap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)