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authorYin Fengwei <fengwei.yin@intel.com>2023-08-02 16:14:05 +0100
committerAndrew Morton <akpm@linux-foundation.org>2023-08-24 16:20:26 -0700
commit617c28ecab22d98a3809370eb6cb50fa24b7bfe1 (patch)
tree931b478360241bfea733004884c9bd04a619ea48 /mm
parent3bd786f76de2e01745f462844fd1a206052ee8b8 (diff)
filemap: batch PTE mappings
Call set_pte_range() once per contiguous range of the folio instead of once per page. This batches the updates to mm counters and the rmap. With a will-it-scale.page_fault3 like app (change file write fault testing to read fault testing. Trying to upstream it to will-it-scale at [1]) got 15% performance gain on a 48C/96T Cascade Lake test box with 96 processes running against xfs. Perf data collected before/after the change: 18.73%--page_add_file_rmap | --11.60%--__mod_lruvec_page_state | |--7.40%--__mod_memcg_lruvec_state | | | --5.58%--cgroup_rstat_updated | --2.53%--__mod_lruvec_state | --1.48%--__mod_node_page_state 9.93%--page_add_file_rmap_range | --2.67%--__mod_lruvec_page_state | |--1.95%--__mod_memcg_lruvec_state | | | --1.57%--cgroup_rstat_updated | --0.61%--__mod_lruvec_state | --0.54%--__mod_node_page_state The running time of __mode_lruvec_page_state() is reduced about 9%. [1]: https://github.com/antonblanchard/will-it-scale/pull/37 Link: https://lkml.kernel.org/r/20230802151406.3735276-38-willy@infradead.org Signed-off-by: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap.c43
1 files changed, 29 insertions, 14 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index c06e9d331416..014b73eb96a1 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3480,11 +3480,12 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
struct file *file = vma->vm_file;
struct page *page = folio_page(folio, start);
unsigned int mmap_miss = READ_ONCE(file->f_ra.mmap_miss);
- unsigned int ref_count = 0, count = 0;
+ unsigned int count = 0;
+ pte_t *old_ptep = vmf->pte;
do {
- if (PageHWPoison(page))
- continue;
+ if (PageHWPoison(page + count))
+ goto skip;
if (mmap_miss > 0)
mmap_miss--;
@@ -3494,20 +3495,34 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
* handled in the specific fault path, and it'll prohibit the
* fault-around logic.
*/
- if (!pte_none(*vmf->pte))
- continue;
-
- if (vmf->address == addr)
- ret = VM_FAULT_NOPAGE;
+ if (!pte_none(vmf->pte[count]))
+ goto skip;
- ref_count++;
- set_pte_range(vmf, folio, page, 1, addr);
- } while (vmf->pte++, page++, addr += PAGE_SIZE, ++count < nr_pages);
+ count++;
+ continue;
+skip:
+ if (count) {
+ set_pte_range(vmf, folio, page, count, addr);
+ folio_ref_add(folio, count);
+ if (in_range(vmf->address, addr, count))
+ ret = VM_FAULT_NOPAGE;
+ }
- /* Restore the vmf->pte */
- vmf->pte -= nr_pages;
+ count++;
+ page += count;
+ vmf->pte += count;
+ addr += count * PAGE_SIZE;
+ count = 0;
+ } while (--nr_pages > 0);
+
+ if (count) {
+ set_pte_range(vmf, folio, page, count, addr);
+ folio_ref_add(folio, count);
+ if (in_range(vmf->address, addr, count))
+ ret = VM_FAULT_NOPAGE;
+ }
- folio_ref_add(folio, ref_count);
+ vmf->pte = old_ptep;
WRITE_ONCE(file->f_ra.mmap_miss, mmap_miss);
return ret;