| Message ID | 20231218153553.807799-7-hch@lst.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [01/17] writeback: fix done_index when hitting the wbc->nr_to_write | expand |
On Mon 18-12-23 16:35:42, Christoph Hellwig wrote: > From: "Matthew Wilcox (Oracle)" <willy@infradead.org> > > Instead of having a 'done' variable that controls the nested loops, > have a writeback_finish() that can be returned directly. This involves > keeping more things in writeback_control, but it's just moving stuff > allocated on the stack to being allocated slightly earlier on the stack. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > [hch: heavily rebased, reordered and commented struct writeback_control] > Signed-off-by: Christoph Hellwig <hch@lst.de> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > include/linux/writeback.h | 6 +++ > mm/page-writeback.c | 79 ++++++++++++++++++++------------------- > 2 files changed, 47 insertions(+), 38 deletions(-) > > diff --git a/include/linux/writeback.h b/include/linux/writeback.h > index 833ec38fc3e0c9..390f2dd03cf27e 100644 > --- a/include/linux/writeback.h > +++ b/include/linux/writeback.h > @@ -11,6 +11,7 @@ > #include <linux/flex_proportions.h> > #include <linux/backing-dev-defs.h> > #include <linux/blk_types.h> > +#include <linux/pagevec.h> > > struct bio; > > @@ -40,6 +41,7 @@ enum writeback_sync_modes { > * in a manner such that unspecified fields are set to zero. > */ > struct writeback_control { > + /* public fields that can be set and/or consumed by the caller: */ > long nr_to_write; /* Write this many pages, and decrement > this for each page written */ > long pages_skipped; /* Pages which were not written */ > @@ -77,6 +79,10 @@ struct writeback_control { > */ > struct swap_iocb **swap_plug; > > + /* internal fields used by the ->writepages implementation: */ > + struct folio_batch fbatch; > + int err; > + > #ifdef CONFIG_CGROUP_WRITEBACK > struct bdi_writeback *wb; /* wb this writeback is issued under */ > struct inode *inode; /* inode being written out */ > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index c798c0d6d0abb4..564d5faf562ba7 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -2360,6 +2360,29 @@ void tag_pages_for_writeback(struct address_space *mapping, > } > EXPORT_SYMBOL(tag_pages_for_writeback); > > +static void writeback_finish(struct address_space *mapping, > + struct writeback_control *wbc, pgoff_t done_index) > +{ > + folio_batch_release(&wbc->fbatch); > + > + /* > + * For range cyclic writeback we need to remember where we stopped so > + * that we can continue there next time we are called. If we hit the > + * last page and there is more work to be done, wrap back to the start > + * of the file. > + * > + * For non-cyclic writeback we always start looking up at the beginning > + * of the file if we are called again, which can only happen due to > + * -ENOMEM from the file system. > + */ > + if (wbc->range_cyclic) { > + if (wbc->err || wbc->nr_to_write <= 0) > + mapping->writeback_index = done_index; > + else > + mapping->writeback_index = 0; > + } > +} > + > /** > * write_cache_pages - walk the list of dirty pages of the given address space and write all of them. > * @mapping: address space structure to write > @@ -2395,17 +2418,12 @@ int write_cache_pages(struct address_space *mapping, > struct writeback_control *wbc, writepage_t writepage, > void *data) > { > - int ret = 0; > - int done = 0; > int error; > - struct folio_batch fbatch; > int nr_folios; > pgoff_t index; > pgoff_t end; /* Inclusive */ > - pgoff_t done_index; > xa_mark_t tag; > > - folio_batch_init(&fbatch); > if (wbc->range_cyclic) { > index = mapping->writeback_index; /* prev offset */ > end = -1; > @@ -2419,22 +2437,23 @@ int write_cache_pages(struct address_space *mapping, > } else { > tag = PAGECACHE_TAG_DIRTY; > } > - done_index = index; > - while (!done && (index <= end)) { > + > + folio_batch_init(&wbc->fbatch); > + wbc->err = 0; > + > + while (index <= end) { > int i; > > nr_folios = filemap_get_folios_tag(mapping, &index, end, > - tag, &fbatch); > + tag, &wbc->fbatch); > > if (nr_folios == 0) > break; > > for (i = 0; i < nr_folios; i++) { > - struct folio *folio = fbatch.folios[i]; > + struct folio *folio = wbc->fbatch.folios[i]; > unsigned long nr; > > - done_index = folio->index; > - > folio_lock(folio); > > /* > @@ -2481,6 +2500,9 @@ int write_cache_pages(struct address_space *mapping, > folio_unlock(folio); > error = 0; > } > + > + if (error && !wbc->err) > + wbc->err = error; > > /* > * For integrity sync we have to keep going until we > @@ -2496,38 +2518,19 @@ int write_cache_pages(struct address_space *mapping, > * off and media errors won't choke writeout for the > * entire file. > */ > - if (error && !ret) > - ret = error; > - if (wbc->sync_mode == WB_SYNC_NONE) { > - if (ret || wbc->nr_to_write <= 0) { > - done_index = folio->index + nr; > - done = 1; > - break; > - } > + if (wbc->sync_mode == WB_SYNC_NONE && > + (wbc->err || wbc->nr_to_write <= 0)) { > + writeback_finish(mapping, wbc, > + folio->index + nr); > + return error; > } > } > - folio_batch_release(&fbatch); > + folio_batch_release(&wbc->fbatch); > cond_resched(); > } > > - /* > - * For range cyclic writeback we need to remember where we stopped so > - * that we can continue there next time we are called. If we hit the > - * last page and there is more work to be done, wrap back to the start > - * of the file. > - * > - * For non-cyclic writeback we always start looking up at the beginning > - * of the file if we are called again, which can only happen due to > - * -ENOMEM from the file system. > - */ > - if (wbc->range_cyclic) { > - if (done) > - mapping->writeback_index = done_index; > - else > - mapping->writeback_index = 0; > - } > - > - return ret; > + writeback_finish(mapping, wbc, 0); > + return 0; > } > EXPORT_SYMBOL(write_cache_pages); > > -- > 2.39.2 >
diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 833ec38fc3e0c9..390f2dd03cf27e 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -11,6 +11,7 @@ #include <linux/flex_proportions.h> #include <linux/backing-dev-defs.h> #include <linux/blk_types.h> +#include <linux/pagevec.h> struct bio; @@ -40,6 +41,7 @@ enum writeback_sync_modes { * in a manner such that unspecified fields are set to zero. */ struct writeback_control { + /* public fields that can be set and/or consumed by the caller: */ long nr_to_write; /* Write this many pages, and decrement this for each page written */ long pages_skipped; /* Pages which were not written */ @@ -77,6 +79,10 @@ struct writeback_control { */ struct swap_iocb **swap_plug; + /* internal fields used by the ->writepages implementation: */ + struct folio_batch fbatch; + int err; + #ifdef CONFIG_CGROUP_WRITEBACK struct bdi_writeback *wb; /* wb this writeback is issued under */ struct inode *inode; /* inode being written out */ diff --git a/mm/page-writeback.c b/mm/page-writeback.c index c798c0d6d0abb4..564d5faf562ba7 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2360,6 +2360,29 @@ void tag_pages_for_writeback(struct address_space *mapping, } EXPORT_SYMBOL(tag_pages_for_writeback); +static void writeback_finish(struct address_space *mapping, + struct writeback_control *wbc, pgoff_t done_index) +{ + folio_batch_release(&wbc->fbatch); + + /* + * For range cyclic writeback we need to remember where we stopped so + * that we can continue there next time we are called. If we hit the + * last page and there is more work to be done, wrap back to the start + * of the file. + * + * For non-cyclic writeback we always start looking up at the beginning + * of the file if we are called again, which can only happen due to + * -ENOMEM from the file system. + */ + if (wbc->range_cyclic) { + if (wbc->err || wbc->nr_to_write <= 0) + mapping->writeback_index = done_index; + else + mapping->writeback_index = 0; + } +} + /** * write_cache_pages - walk the list of dirty pages of the given address space and write all of them. * @mapping: address space structure to write @@ -2395,17 +2418,12 @@ int write_cache_pages(struct address_space *mapping, struct writeback_control *wbc, writepage_t writepage, void *data) { - int ret = 0; - int done = 0; int error; - struct folio_batch fbatch; int nr_folios; pgoff_t index; pgoff_t end; /* Inclusive */ - pgoff_t done_index; xa_mark_t tag; - folio_batch_init(&fbatch); if (wbc->range_cyclic) { index = mapping->writeback_index; /* prev offset */ end = -1; @@ -2419,22 +2437,23 @@ int write_cache_pages(struct address_space *mapping, } else { tag = PAGECACHE_TAG_DIRTY; } - done_index = index; - while (!done && (index <= end)) { + + folio_batch_init(&wbc->fbatch); + wbc->err = 0; + + while (index <= end) { int i; nr_folios = filemap_get_folios_tag(mapping, &index, end, - tag, &fbatch); + tag, &wbc->fbatch); if (nr_folios == 0) break; for (i = 0; i < nr_folios; i++) { - struct folio *folio = fbatch.folios[i]; + struct folio *folio = wbc->fbatch.folios[i]; unsigned long nr; - done_index = folio->index; - folio_lock(folio); /* @@ -2481,6 +2500,9 @@ int write_cache_pages(struct address_space *mapping, folio_unlock(folio); error = 0; } + + if (error && !wbc->err) + wbc->err = error; /* * For integrity sync we have to keep going until we @@ -2496,38 +2518,19 @@ int write_cache_pages(struct address_space *mapping, * off and media errors won't choke writeout for the * entire file. */ - if (error && !ret) - ret = error; - if (wbc->sync_mode == WB_SYNC_NONE) { - if (ret || wbc->nr_to_write <= 0) { - done_index = folio->index + nr; - done = 1; - break; - } + if (wbc->sync_mode == WB_SYNC_NONE && + (wbc->err || wbc->nr_to_write <= 0)) { + writeback_finish(mapping, wbc, + folio->index + nr); + return error; } } - folio_batch_release(&fbatch); + folio_batch_release(&wbc->fbatch); cond_resched(); } - /* - * For range cyclic writeback we need to remember where we stopped so - * that we can continue there next time we are called. If we hit the - * last page and there is more work to be done, wrap back to the start - * of the file. - * - * For non-cyclic writeback we always start looking up at the beginning - * of the file if we are called again, which can only happen due to - * -ENOMEM from the file system. - */ - if (wbc->range_cyclic) { - if (done) - mapping->writeback_index = done_index; - else - mapping->writeback_index = 0; - } - - return ret; + writeback_finish(mapping, wbc, 0); + return 0; } EXPORT_SYMBOL(write_cache_pages);