| Message ID | 20240625090646.1194644-4-gshan@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/filemap: Limit page cache size to that supported by xarray | expand |
On 25.06.24 11:06, Gavin Shan wrote: > In page_cache_ra_order(), the maximal order of the page cache to be > allocated shouldn't be larger than MAX_PAGECACHE_ORDER. Otherwise, > it's possible the large page cache can't be supported by xarray when > the corresponding xarray entry is split. > > For example, HPAGE_PMD_ORDER is 13 on ARM64 when the base page size > is 64KB. The PMD-sized page cache can't be supported by xarray. > > Suggested-by: David Hildenbrand <david@redhat.com> Heh, you came up with this yourself concurrently :) so feel free to drop that. Acked-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Gavin Shan <gshan@redhat.com> > --- > mm/readahead.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/mm/readahead.c b/mm/readahead.c > index c1b23989d9ca..817b2a352d78 100644 > --- a/mm/readahead.c > +++ b/mm/readahead.c > @@ -503,11 +503,11 @@ void page_cache_ra_order(struct readahead_control *ractl, > > limit = min(limit, index + ra->size - 1); > > - if (new_order < MAX_PAGECACHE_ORDER) { > + if (new_order < MAX_PAGECACHE_ORDER) > new_order += 2; > - new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order); > - new_order = min_t(unsigned int, new_order, ilog2(ra->size)); > - } > + > + new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order); > + new_order = min_t(unsigned int, new_order, ilog2(ra->size)); > > /* See comment in page_cache_ra_unbounded() */ > nofs = memalloc_nofs_save();
On 6/26/24 4:45 AM, David Hildenbrand wrote: > On 25.06.24 11:06, Gavin Shan wrote: >> In page_cache_ra_order(), the maximal order of the page cache to be >> allocated shouldn't be larger than MAX_PAGECACHE_ORDER. Otherwise, >> it's possible the large page cache can't be supported by xarray when >> the corresponding xarray entry is split. >> >> For example, HPAGE_PMD_ORDER is 13 on ARM64 when the base page size >> is 64KB. The PMD-sized page cache can't be supported by xarray. >> >> Suggested-by: David Hildenbrand <david@redhat.com> > > Heh, you came up with this yourself concurrently :) so feel free to drop that. > > Acked-by: David Hildenbrand <david@redhat.com> > David, thanks for your follow-up and reviews. I will drop that tag in next respin :) Thanks, Gavin >> Signed-off-by: Gavin Shan <gshan@redhat.com> >> --- >> mm/readahead.c | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/mm/readahead.c b/mm/readahead.c >> index c1b23989d9ca..817b2a352d78 100644 >> --- a/mm/readahead.c >> +++ b/mm/readahead.c >> @@ -503,11 +503,11 @@ void page_cache_ra_order(struct readahead_control *ractl, >> limit = min(limit, index + ra->size - 1); >> - if (new_order < MAX_PAGECACHE_ORDER) { >> + if (new_order < MAX_PAGECACHE_ORDER) >> new_order += 2; >> - new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order); >> - new_order = min_t(unsigned int, new_order, ilog2(ra->size)); >> - } >> + >> + new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order); >> + new_order = min_t(unsigned int, new_order, ilog2(ra->size)); >> /* See comment in page_cache_ra_unbounded() */ >> nofs = memalloc_nofs_save(); >
diff --git a/mm/readahead.c b/mm/readahead.c index c1b23989d9ca..817b2a352d78 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -503,11 +503,11 @@ void page_cache_ra_order(struct readahead_control *ractl, limit = min(limit, index + ra->size - 1); - if (new_order < MAX_PAGECACHE_ORDER) { + if (new_order < MAX_PAGECACHE_ORDER) new_order += 2; - new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order); - new_order = min_t(unsigned int, new_order, ilog2(ra->size)); - } + + new_order = min_t(unsigned int, MAX_PAGECACHE_ORDER, new_order); + new_order = min_t(unsigned int, new_order, ilog2(ra->size)); /* See comment in page_cache_ra_unbounded() */ nofs = memalloc_nofs_save();
In page_cache_ra_order(), the maximal order of the page cache to be allocated shouldn't be larger than MAX_PAGECACHE_ORDER. Otherwise, it's possible the large page cache can't be supported by xarray when the corresponding xarray entry is split. For example, HPAGE_PMD_ORDER is 13 on ARM64 when the base page size is 64KB. The PMD-sized page cache can't be supported by xarray. Suggested-by: David Hildenbrand <david@redhat.com> Signed-off-by: Gavin Shan <gshan@redhat.com> --- mm/readahead.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)