| Message ID | 20220316131723.111553-22-jefflexu@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fscache,erofs: fscache-based on-demand read semantics | expand |
On Wed, Mar 16, 2022 at 09:17:22PM +0800, Jeffle Xu wrote: > This patch implements fscache-based data readahead. Also registers an > individual bdi for each erofs instance to enable readahead. > > Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> > --- > fs/erofs/fscache.c | 153 +++++++++++++++++++++++++++++++++++++++++++++ > fs/erofs/super.c | 4 ++ > 2 files changed, 157 insertions(+) > > diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c > index 82c52b6e077e..913ca891deb9 100644 > --- a/fs/erofs/fscache.c > +++ b/fs/erofs/fscache.c > @@ -10,6 +10,13 @@ struct erofs_fscache_map { > u64 m_llen; > }; > > +struct erofs_fscahce_ra_ctx { typo, should be `erofs_fscache_ra_ctx' > + struct readahead_control *rac; > + struct address_space *mapping; > + loff_t start; > + size_t len, done; > +}; > + > static struct fscache_volume *volume; > > /* > @@ -199,12 +206,158 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) > return ret; > } > > +static inline size_t erofs_fscache_calc_len(struct erofs_fscahce_ra_ctx *ractx, > + struct erofs_fscache_map *fsmap) > +{ > + /* > + * 1) For CHUNK_BASED layout, the output m_la is rounded down to the > + * nearest chunk boundary, and the output m_llen actually starts from > + * the start of the containing chunk. > + * 2) For other cases, the output m_la is equal to o_la. > + */ > + size_t len = fsmap->m_llen - (fsmap->o_la - fsmap->m_la); > + > + return min_t(size_t, len, ractx->len - ractx->done); > +} > + > +static inline void erofs_fscache_unlock_pages(struct readahead_control *rac, > + size_t len) Can we convert them into folios in advance? it seems much straight-forward to convert these... Or I have to convert them later, and it seems unnecessary... > +{ > + while (len) { > + struct page *page = readahead_page(rac); > + > + SetPageUptodate(page); > + unlock_page(page); > + put_page(page); > + > + len -= PAGE_SIZE; > + } > +} > + > +static int erofs_fscache_ra_hole(struct erofs_fscahce_ra_ctx *ractx, > + struct erofs_fscache_map *fsmap) > +{ > + struct iov_iter iter; > + loff_t start = ractx->start + ractx->done; > + size_t length = erofs_fscache_calc_len(ractx, fsmap); > + > + iov_iter_xarray(&iter, READ, &ractx->mapping->i_pages, start, length); > + iov_iter_zero(length, &iter); > + > + erofs_fscache_unlock_pages(ractx->rac, length); > + return length; > +} > + > +static int erofs_fscache_ra_noinline(struct erofs_fscahce_ra_ctx *ractx, > + struct erofs_fscache_map *fsmap) > +{ > + struct fscache_cookie *cookie = fsmap->m_ctx->cookie; > + loff_t start = ractx->start + ractx->done; > + size_t length = erofs_fscache_calc_len(ractx, fsmap); > + loff_t pstart = fsmap->m_pa + (fsmap->o_la - fsmap->m_la); > + int ret; > + > + ret = erofs_fscache_read_pages(cookie, ractx->mapping, > + start, length, pstart); > + if (!ret) { > + erofs_fscache_unlock_pages(ractx->rac, length); > + ret = length; > + } > + > + return ret; > +} > + > +static int erofs_fscache_ra_inline(struct erofs_fscahce_ra_ctx *ractx, > + struct erofs_fscache_map *fsmap) > +{ We could fold in this, since it has the only user. Thanks, Gao Xiang
On 3/17/22 1:22 PM, Gao Xiang wrote: > On Wed, Mar 16, 2022 at 09:17:22PM +0800, Jeffle Xu wrote: >> This patch implements fscache-based data readahead. Also registers an >> individual bdi for each erofs instance to enable readahead. >> >> Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> >> --- >> fs/erofs/fscache.c | 153 +++++++++++++++++++++++++++++++++++++++++++++ >> fs/erofs/super.c | 4 ++ >> 2 files changed, 157 insertions(+) >> >> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c >> index 82c52b6e077e..913ca891deb9 100644 >> --- a/fs/erofs/fscache.c >> +++ b/fs/erofs/fscache.c >> @@ -10,6 +10,13 @@ struct erofs_fscache_map { >> u64 m_llen; >> }; >> >> +struct erofs_fscahce_ra_ctx { > > typo, should be `erofs_fscache_ra_ctx' Oops. Thanks. > >> + struct readahead_control *rac; >> + struct address_space *mapping; >> + loff_t start; >> + size_t len, done; >> +}; >> + >> static struct fscache_volume *volume; >> >> /* >> @@ -199,12 +206,158 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) >> return ret; >> } >> >> +static inline size_t erofs_fscache_calc_len(struct erofs_fscahce_ra_ctx *ractx, >> + struct erofs_fscache_map *fsmap) >> +{ >> + /* >> + * 1) For CHUNK_BASED layout, the output m_la is rounded down to the >> + * nearest chunk boundary, and the output m_llen actually starts from >> + * the start of the containing chunk. >> + * 2) For other cases, the output m_la is equal to o_la. >> + */ >> + size_t len = fsmap->m_llen - (fsmap->o_la - fsmap->m_la); >> + >> + return min_t(size_t, len, ractx->len - ractx->done); >> +} >> + >> +static inline void erofs_fscache_unlock_pages(struct readahead_control *rac, >> + size_t len) > > Can we convert them into folios in advance? it seems much > straight-forward to convert these... > > Or I have to convert them later, and it seems unnecessary... OK I will try to use folio API in the next version. > > >> +{ >> + while (len) { >> + struct page *page = readahead_page(rac); >> + >> + SetPageUptodate(page); >> + unlock_page(page); >> + put_page(page); >> + >> + len -= PAGE_SIZE; >> + } >> +} >> + >> +static int erofs_fscache_ra_hole(struct erofs_fscahce_ra_ctx *ractx, >> + struct erofs_fscache_map *fsmap) >> +{ >> + struct iov_iter iter; >> + loff_t start = ractx->start + ractx->done; >> + size_t length = erofs_fscache_calc_len(ractx, fsmap); >> + >> + iov_iter_xarray(&iter, READ, &ractx->mapping->i_pages, start, length); >> + iov_iter_zero(length, &iter); >> + >> + erofs_fscache_unlock_pages(ractx->rac, length); >> + return length; >> +} >> + >> +static int erofs_fscache_ra_noinline(struct erofs_fscahce_ra_ctx *ractx, >> + struct erofs_fscache_map *fsmap) >> +{ >> + struct fscache_cookie *cookie = fsmap->m_ctx->cookie; >> + loff_t start = ractx->start + ractx->done; >> + size_t length = erofs_fscache_calc_len(ractx, fsmap); >> + loff_t pstart = fsmap->m_pa + (fsmap->o_la - fsmap->m_la); >> + int ret; >> + >> + ret = erofs_fscache_read_pages(cookie, ractx->mapping, >> + start, length, pstart); >> + if (!ret) { >> + erofs_fscache_unlock_pages(ractx->rac, length); >> + ret = length; >> + } >> + >> + return ret; >> +} >> + >> +static int erofs_fscache_ra_inline(struct erofs_fscahce_ra_ctx *ractx, >> + struct erofs_fscache_map *fsmap) >> +{ > > We could fold in this, since it has the only user. OK, and "struct erofs_fscahce_ra_ctx" is not needed then.
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index 82c52b6e077e..913ca891deb9 100644 --- a/fs/erofs/fscache.c +++ b/fs/erofs/fscache.c @@ -10,6 +10,13 @@ struct erofs_fscache_map { u64 m_llen; }; +struct erofs_fscahce_ra_ctx { + struct readahead_control *rac; + struct address_space *mapping; + loff_t start; + size_t len, done; +}; + static struct fscache_volume *volume; /* @@ -199,12 +206,158 @@ static int erofs_fscache_readpage(struct file *file, struct page *page) return ret; } +static inline size_t erofs_fscache_calc_len(struct erofs_fscahce_ra_ctx *ractx, + struct erofs_fscache_map *fsmap) +{ + /* + * 1) For CHUNK_BASED layout, the output m_la is rounded down to the + * nearest chunk boundary, and the output m_llen actually starts from + * the start of the containing chunk. + * 2) For other cases, the output m_la is equal to o_la. + */ + size_t len = fsmap->m_llen - (fsmap->o_la - fsmap->m_la); + + return min_t(size_t, len, ractx->len - ractx->done); +} + +static inline void erofs_fscache_unlock_pages(struct readahead_control *rac, + size_t len) +{ + while (len) { + struct page *page = readahead_page(rac); + + SetPageUptodate(page); + unlock_page(page); + put_page(page); + + len -= PAGE_SIZE; + } +} + +static int erofs_fscache_ra_hole(struct erofs_fscahce_ra_ctx *ractx, + struct erofs_fscache_map *fsmap) +{ + struct iov_iter iter; + loff_t start = ractx->start + ractx->done; + size_t length = erofs_fscache_calc_len(ractx, fsmap); + + iov_iter_xarray(&iter, READ, &ractx->mapping->i_pages, start, length); + iov_iter_zero(length, &iter); + + erofs_fscache_unlock_pages(ractx->rac, length); + return length; +} + +static int erofs_fscache_ra_noinline(struct erofs_fscahce_ra_ctx *ractx, + struct erofs_fscache_map *fsmap) +{ + struct fscache_cookie *cookie = fsmap->m_ctx->cookie; + loff_t start = ractx->start + ractx->done; + size_t length = erofs_fscache_calc_len(ractx, fsmap); + loff_t pstart = fsmap->m_pa + (fsmap->o_la - fsmap->m_la); + int ret; + + ret = erofs_fscache_read_pages(cookie, ractx->mapping, + start, length, pstart); + if (!ret) { + erofs_fscache_unlock_pages(ractx->rac, length); + ret = length; + } + + return ret; +} + +static int erofs_fscache_ra_inline(struct erofs_fscahce_ra_ctx *ractx, + struct erofs_fscache_map *fsmap) +{ + struct page *page = readahead_page(ractx->rac); + int ret; + + ret = erofs_fscache_readpage_inline(page, fsmap); + if (!ret) { + SetPageUptodate(page); + ret = PAGE_SIZE; + } + + unlock_page(page); + put_page(page); + return ret; +} + +static void erofs_fscache_readahead(struct readahead_control *rac) +{ + struct inode *inode = rac->mapping->host; + struct erofs_inode *vi = EROFS_I(inode); + struct super_block *sb = inode->i_sb; + struct erofs_fscahce_ra_ctx ractx; + int ret; + + if (erofs_inode_is_data_compressed(vi->datalayout)) { + erofs_info(sb, "compressed layout not supported yet"); + return; + } + + if (!readahead_count(rac)) + return; + + ractx = (struct erofs_fscahce_ra_ctx) { + .rac = rac, + .mapping = rac->mapping, + .start = readahead_pos(rac), + .len = readahead_length(rac), + }; + + do { + struct erofs_map_blocks map; + struct erofs_fscache_map fsmap; + + map.m_la = fsmap.o_la = ractx.start + ractx.done; + + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); + if (ret) + return; + + if (!(map.m_flags & EROFS_MAP_MAPPED)) { + /* + * Two cases will hit this: + * 1) EOF. Imposibble in readahead routine; + * 2) hole. Only CHUNK_BASED layout supports hole. + */ + fsmap.m_la = map.m_la; + fsmap.m_llen = map.m_llen; + ret = erofs_fscache_ra_hole(&ractx, &fsmap); + continue; + } + + ret = erofs_fscache_get_map(&fsmap, &map, sb); + if (ret) + return; + + if (map.m_flags & EROFS_MAP_META) { + ret = erofs_fscache_ra_inline(&ractx, &fsmap); + continue; + } + + switch (vi->datalayout) { + case EROFS_INODE_FLAT_PLAIN: + case EROFS_INODE_FLAT_INLINE: + case EROFS_INODE_CHUNK_BASED: + ret = erofs_fscache_ra_noinline(&ractx, &fsmap); + break; + default: + DBG_BUGON(1); + return; + } + } while (ret > 0 && ((ractx.done += ret) < ractx.len)); +} + static const struct address_space_operations erofs_fscache_blob_aops = { .readpage = erofs_fscache_readpage_blob, }; const struct address_space_operations erofs_fscache_access_aops = { .readpage = erofs_fscache_readpage, + .readahead = erofs_fscache_readahead, }; struct page *erofs_fscache_read_cache_page(struct erofs_fscache_context *ctx, diff --git a/fs/erofs/super.c b/fs/erofs/super.c index f058a04a00c7..2942029a7049 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -616,6 +616,10 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) return PTR_ERR(bootstrap); sbi->bootstrap = bootstrap; + + err = super_setup_bdi(sb); + if (err) + return err; } err = erofs_read_superblock(sb);
This patch implements fscache-based data readahead. Also registers an individual bdi for each erofs instance to enable readahead. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> --- fs/erofs/fscache.c | 153 +++++++++++++++++++++++++++++++++++++++++++++ fs/erofs/super.c | 4 ++ 2 files changed, 157 insertions(+)