summaryrefslogtreecommitdiff
path: root/mm/truncate.c
diff options
context:
space:
mode:
authorMatthew Wilcox (Oracle) <willy@infradead.org>2021-05-04 18:32:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-05 11:27:19 -0700
commit7716506adac4664793a9d6d3dfa31ffddfa98714 (patch)
treeec099a414e8120e3e68e2e6022eed8fa6fff5a3b /mm/truncate.c
parent4d75136be8bf3ae01b0bc3e725b2cdc921e103bd (diff)
mm: introduce and use mapping_empty()
Patch series "Remove nrexceptional tracking", v2. We actually use nrexceptional for very little these days. It's a minor pain to keep in sync with nrpages, but the pain becomes much bigger with the THP patches because we don't know how many indices a shadow entry occupies. It's easier to just remove it than keep it accurate. Also, we save 8 bytes per inode which is nothing to sneeze at; on my laptop, it would improve shmem_inode_cache from 22 to 23 objects per 16kB, and inode_cache from 26 to 27 objects. Combined, that saves a megabyte of memory from a combined usage of 25MB for both caches. Unfortunately, ext4 doesn't cross a magic boundary, so it doesn't save any memory for ext4. This patch (of 4): Instead of checking the two counters (nrpages and nrexceptional), we can just check whether i_pages is empty. Link: https://lkml.kernel.org/r/20201026151849.24232-1-willy@infradead.org Link: https://lkml.kernel.org/r/20201026151849.24232-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Tested-by: Vishal Verma <vishal.l.verma@intel.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/truncate.c')
-rw-r--r--mm/truncate.c18
1 files changed, 3 insertions, 15 deletions
diff --git a/mm/truncate.c b/mm/truncate.c
index 455944264663..adb8d4107988 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -295,7 +295,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
pgoff_t index;
int i;
- if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
+ if (mapping_empty(mapping))
goto out;
/* Offsets within partial pages */
@@ -440,9 +440,6 @@ EXPORT_SYMBOL(truncate_inode_pages);
*/
void truncate_inode_pages_final(struct address_space *mapping)
{
- unsigned long nrexceptional;
- unsigned long nrpages;
-
/*
* Page reclaim can not participate in regular inode lifetime
* management (can't call iput()) and thus can race with the
@@ -452,16 +449,7 @@ void truncate_inode_pages_final(struct address_space *mapping)
*/
mapping_set_exiting(mapping);
- /*
- * When reclaim installs eviction entries, it increases
- * nrexceptional first, then decreases nrpages. Make sure we see
- * this in the right order or we might miss an entry.
- */
- nrpages = mapping->nrpages;
- smp_rmb();
- nrexceptional = mapping->nrexceptional;
-
- if (nrpages || nrexceptional) {
+ if (!mapping_empty(mapping)) {
/*
* As truncation uses a lockless tree lookup, cycle
* the tree lock to make sure any ongoing tree
@@ -633,7 +621,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
int ret2 = 0;
int did_range_unmap = 0;
- if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
+ if (mapping_empty(mapping))
goto out;
pagevec_init(&pvec);