Commit dcdf11ee authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

mm, shmem: add vmstat for hugepage fallback 



The existing thp_fault_fallback indicates when thp attempts to allocate a
hugepage but fails, or if the hugepage cannot be charged to the mem cgroup
hierarchy.

Extend this to shmem as well.  Adds a new thp_file_fallback to complement
thp_file_alloc that gets incremented when a hugepage is attempted to be
allocated but fails, or if it cannot be charged to the mem cgroup
hierarchy.

Additionally, remove the check for CONFIG_TRANSPARENT_HUGE_PAGECACHE from
shmem_alloc_hugepage() since it is only called with this configuration
option.

Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarYang Shi <yang.shi@linux.alibaba.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Jeremy Cline <jcline@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.2003061421240.7412@chino.kir.corp.google.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6aeff241

Documentation/admin-guide/mm/transhuge.rst

+4 −0
Original line number Diff line number Diff line
@@ -319,6 +319,10 @@ thp_file_alloc 
	is incremented every time a file huge page is successfully

	allocated.



thp_file_fallback

	is incremented if a file huge page is attempted to be allocated

	but fails and instead falls back to using small pages.



thp_file_mapped

	is incremented every time a file huge page is mapped into

	user address space.

include/linux/vm_event_item.h

+2 −0
Original line number Diff line number Diff line
@@ -76,6 +76,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, 
		THP_COLLAPSE_ALLOC,

		THP_COLLAPSE_ALLOC_FAILED,

		THP_FILE_ALLOC,

		THP_FILE_FALLBACK,

		THP_FILE_MAPPED,

		THP_SPLIT_PAGE,

		THP_SPLIT_PAGE_FAILED,
@@ -115,6 +116,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, 


#ifndef CONFIG_TRANSPARENT_HUGEPAGE

#define THP_FILE_ALLOC ({ BUILD_BUG(); 0; })

#define THP_FILE_FALLBACK ({ BUILD_BUG(); 0; })

#define THP_FILE_MAPPED ({ BUILD_BUG(); 0; })

#endif

mm/shmem.c

+6 −4
Original line number Diff line number Diff line
@@ -1472,9 +1472,6 @@ static struct page *shmem_alloc_hugepage(gfp_t gfp, 
	pgoff_t hindex;

	struct page *page;



	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))

		return NULL;



	hindex = round_down(index, HPAGE_PMD_NR);

	if (xa_find(&mapping->i_pages, &hindex, hindex + HPAGE_PMD_NR - 1,

								XA_PRESENT))
@@ -1486,6 +1483,8 @@ static struct page *shmem_alloc_hugepage(gfp_t gfp, 
	shmem_pseudo_vma_destroy(&pvma);

	if (page)

		prep_transhuge_page(page);

	else

		count_vm_event(THP_FILE_FALLBACK);

	return page;

}
@@ -1871,8 +1870,11 @@ alloc_nohuge: 


	error = mem_cgroup_try_charge_delay(page, charge_mm, gfp, &memcg,

					    PageTransHuge(page));

	if (error)

	if (error) {

		if (PageTransHuge(page))

			count_vm_event(THP_FILE_FALLBACK);

		goto unacct;

	}

	error = shmem_add_to_page_cache(page, mapping, hindex,

					NULL, gfp & GFP_RECLAIM_MASK);

	if (error) {

mm/vmstat.c

+1 −0
Original line number Diff line number Diff line
@@ -1259,6 +1259,7 @@ const char * const vmstat_text[] = { 
	"thp_collapse_alloc",

	"thp_collapse_alloc_failed",

	"thp_file_alloc",

	"thp_file_fallback",

	"thp_file_mapped",

	"thp_split_page",

	"thp_split_page_failed",

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