From bebeb3d68b24bb4132d452c5707fe321208bcbcd Mon Sep 17 00:00:00 2001 From: Michel Lespinasse Date: Fri, 22 Feb 2013 16:32:37 -0800 Subject: mm: introduce mm_populate() for populating new vmas When creating new mappings using the MAP_POPULATE / MAP_LOCKED flags (or with MCL_FUTURE in effect), we want to populate the pages within the newly created vmas. This may take a while as we may have to read pages from disk, so ideally we want to do this outside of the write-locked mmap_sem region. This change introduces mm_populate(), which is used to defer populating such mappings until after the mmap_sem write lock has been released. This is implemented as a generalization of the former do_mlock_pages(), which accomplished the same task but was using during mlock() / mlockall(). Signed-off-by: Michel Lespinasse Reported-by: Andy Lutomirski Acked-by: Rik van Riel Tested-by: Andy Lutomirski Cc: Greg Ungerer Cc: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/aio.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/aio.c b/fs/aio.c index 71f613cf4a85..82eec7c7b4bb 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -103,6 +103,7 @@ static int aio_setup_ring(struct kioctx *ctx) unsigned nr_events = ctx->max_reqs; unsigned long size; int nr_pages; + bool populate; /* Compensate for the ring buffer's head/tail overlap entry */ nr_events += 2; /* 1 is required, 2 for good luck */ @@ -129,7 +130,8 @@ static int aio_setup_ring(struct kioctx *ctx) down_write(&ctx->mm->mmap_sem); info->mmap_base = do_mmap_pgoff(NULL, 0, info->mmap_size, PROT_READ|PROT_WRITE, - MAP_ANONYMOUS|MAP_PRIVATE, 0); + MAP_ANONYMOUS|MAP_PRIVATE, 0, + &populate); if (IS_ERR((void *)info->mmap_base)) { up_write(&ctx->mm->mmap_sem); info->mmap_size = 0; @@ -147,6 +149,8 @@ static int aio_setup_ring(struct kioctx *ctx) aio_free_ring(ctx); return -EAGAIN; } + if (populate) + mm_populate(info->mmap_base, info->mmap_size); ctx->user_id = info->mmap_base; -- cgit v1.2.3