| Message ID | 1394019878-25979-2-git-send-email-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 5 Mar 2014, Chris Wilson wrote: > The intention of returning ENOSPC for a page allocation failure due to > memory exhausstion in shmem_getpage_gfp() is purely "so that a failure > on a sparse tmpfs mapping will give SIGBUS not OOM." However, for other > callers, for example i915.ko, we want to distinguish the error message > reported to userspace between ENOSPC (meaning that we were unable to fit > the object/execbuffer into the aperture) and ENOMEM (meaning that we > were unable to allocate pages for the object). > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Hugh Dickins <hughd@google.com> I'm not keen on this: perhaps because it looks like a hack of yours - and draws attention to what might be thought a hack of mine ;) Nor am I thrilled by what was there before (we have three cases which ought to be distinguished, but only ENOMEM and ENOSPC to distinguish between them); but would rather it stay as is, than change what's reported to the user after all these years. But I do see your point, and asking you to convert ENOSPC to ENOMEM in all your drivers/gpu calls might be tiresome. I think we have a reasonable compromise: shmem_read_mapping_page_gfp() is already the wrapper provided just for you guys, how about posting a patch to map ENOSPC to ENOMEM there? (You're using the MS_KERNMOUNT, so won't hit a max_blocks limit.) Hugh > --- > mm/shmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index 1f18c9d0d93e..142b0bc085e1 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1179,7 +1179,7 @@ repeat: > > } else { > if (shmem_acct_block(info->flags)) { > - error = -ENOSPC; > + error = fault_type ? -ENOSPC : -ENOMEM; > goto failed; > } > if (sbinfo->max_blocks) { > -- > 1.9.0
diff --git a/mm/shmem.c b/mm/shmem.c index 1f18c9d0d93e..142b0bc085e1 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1179,7 +1179,7 @@ repeat: } else { if (shmem_acct_block(info->flags)) { - error = -ENOSPC; + error = fault_type ? -ENOSPC : -ENOMEM; goto failed; } if (sbinfo->max_blocks) {
The intention of returning ENOSPC for a page allocation failure due to memory exhausstion in shmem_getpage_gfp() is purely "so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM." However, for other callers, for example i915.ko, we want to distinguish the error message reported to userspace between ENOSPC (meaning that we were unable to fit the object/execbuffer into the aperture) and ENOMEM (meaning that we were unable to allocate pages for the object). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Hugh Dickins <hughd@google.com> --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)