| Message ID | 20240201100835.1626685-2-liushixin2@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fix I/O high when memory almost met memcg limit | expand |
On Thu 01-02-24 18:08:34, Liu Shixin wrote: > When a task in memcg readaheads file pages, page_cache_ra_unbounded() > will try to readahead nr_to_read pages. Even if the new allocated page > fails to charge, page_cache_ra_unbounded() still tries to readahead > next page. This leads to too much memory reclaim. > > Stop readahead if mem_cgroup_charge() fails, i.e. add_to_page_cache_lru() > returns -ENOMEM. > > Signed-off-by: Liu Shixin <liushixin2@huawei.com> > Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com> Makes sense. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > mm/readahead.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/mm/readahead.c b/mm/readahead.c > index 23620c57c1225..cc4abb67eb223 100644 > --- a/mm/readahead.c > +++ b/mm/readahead.c > @@ -228,6 +228,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, > */ > for (i = 0; i < nr_to_read; i++) { > struct folio *folio = xa_load(&mapping->i_pages, index + i); > + int ret; > > if (folio && !xa_is_value(folio)) { > /* > @@ -247,9 +248,12 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, > folio = filemap_alloc_folio(gfp_mask, 0); > if (!folio) > break; > - if (filemap_add_folio(mapping, folio, index + i, > - gfp_mask) < 0) { > + > + ret = filemap_add_folio(mapping, folio, index + i, gfp_mask); > + if (ret < 0) { > folio_put(folio); > + if (ret == -ENOMEM) > + break; > read_pages(ractl); > ractl->_index++; > i = ractl->_index + ractl->_nr_pages - index - 1; > -- > 2.25.1 >
On Thu, Feb 01, 2024 at 06:08:34PM +0800, Liu Shixin wrote: > @@ -247,9 +248,12 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, > folio = filemap_alloc_folio(gfp_mask, 0); > if (!folio) > break; > - if (filemap_add_folio(mapping, folio, index + i, > - gfp_mask) < 0) { > + > + ret = filemap_add_folio(mapping, folio, index + i, gfp_mask); > + if (ret < 0) { > folio_put(folio); > + if (ret == -ENOMEM) > + break; No, that's too early. You've still got a batch of pages which were successfully added; you have to read them. You were only off by one line though ;-) > read_pages(ractl); > ractl->_index++; > i = ractl->_index + ractl->_nr_pages - index - 1; > -- > 2.25.1 > >
On Thu 01-02-24 13:47:03, Matthew Wilcox wrote: > On Thu, Feb 01, 2024 at 06:08:34PM +0800, Liu Shixin wrote: > > @@ -247,9 +248,12 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, > > folio = filemap_alloc_folio(gfp_mask, 0); > > if (!folio) > > break; > > - if (filemap_add_folio(mapping, folio, index + i, > > - gfp_mask) < 0) { > > + > > + ret = filemap_add_folio(mapping, folio, index + i, gfp_mask); > > + if (ret < 0) { > > folio_put(folio); > > + if (ret == -ENOMEM) > > + break; > > No, that's too early. You've still got a batch of pages which were > successfully added; you have to read them. You were only off by one > line though ;-) There's a read_pages() call just outside of the loop so this break is actually fine AFAICT. Honza
On Thu, Feb 01, 2024 at 02:52:31PM +0100, Jan Kara wrote: > On Thu 01-02-24 13:47:03, Matthew Wilcox wrote: > > On Thu, Feb 01, 2024 at 06:08:34PM +0800, Liu Shixin wrote: > > > @@ -247,9 +248,12 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, > > > folio = filemap_alloc_folio(gfp_mask, 0); > > > if (!folio) > > > break; > > > - if (filemap_add_folio(mapping, folio, index + i, > > > - gfp_mask) < 0) { > > > + > > > + ret = filemap_add_folio(mapping, folio, index + i, gfp_mask); > > > + if (ret < 0) { > > > folio_put(folio); > > > + if (ret == -ENOMEM) > > > + break; > > > > No, that's too early. You've still got a batch of pages which were > > successfully added; you have to read them. You were only off by one > > line though ;-) > > There's a read_pages() call just outside of the loop so this break is > actually fine AFAICT. Oh, good point! I withdraw my criticism.
diff --git a/mm/readahead.c b/mm/readahead.c index 23620c57c1225..cc4abb67eb223 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -228,6 +228,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, */ for (i = 0; i < nr_to_read; i++) { struct folio *folio = xa_load(&mapping->i_pages, index + i); + int ret; if (folio && !xa_is_value(folio)) { /* @@ -247,9 +248,12 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, folio = filemap_alloc_folio(gfp_mask, 0); if (!folio) break; - if (filemap_add_folio(mapping, folio, index + i, - gfp_mask) < 0) { + + ret = filemap_add_folio(mapping, folio, index + i, gfp_mask); + if (ret < 0) { folio_put(folio); + if (ret == -ENOMEM) + break; read_pages(ractl); ractl->_index++; i = ractl->_index + ractl->_nr_pages - index - 1;