Commit 09c231cb authored Jul 31, 2012 by Nathan Zimmer Committed by Linus Torvalds Jul 31, 2012

tmpfs: distribute interleave better across nodes



When tmpfs has the interleave memory policy, it always starts allocating
for each file from node 0 at offset 0.  When there are many small files,
the lower nodes fill up disproportionately.

This patch spreads out node usage by starting files at nodes other than 0,
by using the inode number to bias the starting node for interleave.

Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 6527af5d

mm/shmem.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -929,7 +929,8 @@ static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,

		/* Create a pseudo vma that just contains the policy */
		pvma.vm_start = 0;
		pvma.vm_pgoff = index;
		/* Bias interleave by inode number to distribute better across nodes */
		pvma.vm_pgoff = index + info->vfs_inode.i_ino;
		pvma.vm_ops = NULL;
		pvma.vm_policy = spol;
		return swapin_readahead(swap, gfp, &pvma, 0);
		@@ -942,7 +943,8 @@ static struct page *shmem_alloc_page(gfp_t gfp,

		/* Create a pseudo vma that just contains the policy */
		pvma.vm_start = 0;
		pvma.vm_pgoff = index;
		/* Bias interleave by inode number to distribute better across nodes */
		pvma.vm_pgoff = index + info->vfs_inode.i_ino;
		pvma.vm_ops = NULL;
		pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);

Admin message