ANDROID: mm: add a new vendor hook in filemap_map_pages

In the current vendor hook, if next_uptodate_folio returns NULL, the
first_pgoff is set to zero, and the last_pgoff is set to start_pgoff.
Therefore, the collection range is from 0 to the start_pgoff.

|-----------|------------|-------------|------------------|
0      start_pgoff  first_pgoff    last_pgoff         end_pgoff

We want to collect the first_pgoff to last_pgoff, so we have to add a
new vendor hook.

Bug: 397274634
Change-Id: I19d54c601e2ffc5de5ec2dafcd43fbdcdc84b0d2
Signed-off-by: zhanghui <[email protected]>
(cherry picked from commit 2a0173a)

Author: zhanghui31

include/trace/hooks/mm.h

@@ -351,9 +351,9 @@ DECLARE_HOOK(android_vh_filemap_read,
 	TP_PROTO(struct file *file, loff_t pos, size_t size),
 	TP_ARGS(file, pos, size));
 DECLARE_HOOK(android_vh_filemap_map_pages,
-	TP_PROTO(struct file *file, pgoff_t first_pgoff,
+	TP_PROTO(struct file *file, pgoff_t orig_start_pgoff, pgoff_t first_pgoff,
 		pgoff_t last_pgoff, vm_fault_t ret),
-	TP_ARGS(file, first_pgoff, last_pgoff, ret));
+	TP_ARGS(file, orig_start_pgoff, first_pgoff, last_pgoff, ret));
 DECLARE_HOOK(android_vh_page_cache_readahead_start,
 	TP_PROTO(struct file *file, pgoff_t pgoff,
 		unsigned int size, bool sync),

mm/filemap.c

@@ -3700,12 +3700,14 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
 	unsigned long rss = 0;
 	unsigned int nr_pages = 0, mmap_miss = 0, mmap_miss_saved, folio_type;
 	pgoff_t first_pgoff = 0;
+	pgoff_t orig_start_pgoff = start_pgoff;
 
 	rcu_read_lock();
 	folio = next_uptodate_folio(&xas, mapping, end_pgoff);
 	if (!folio)
 		goto out;
 	first_pgoff = xas.xa_index;
+	orig_start_pgoff = xas.xa_index;
 
 	if (filemap_map_pmd(vmf, folio, start_pgoff)) {
 		ret = VM_FAULT_NOPAGE;
@@ -3756,7 +3758,8 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
 		WRITE_ONCE(file->f_ra.mmap_miss, 0);
 	else
 		WRITE_ONCE(file->f_ra.mmap_miss, mmap_miss_saved - mmap_miss);
-	trace_android_vh_filemap_map_pages(file, first_pgoff, last_pgoff, ret);
+	trace_android_vh_filemap_map_pages(file, orig_start_pgoff,
+					first_pgoff, last_pgoff, ret);
 
 	return ret;
 }