| Message ID | 20170404221128.3943-18-matthew.auld@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Apr 04, 2017 at 11:11:27PM +0100, Matthew Auld wrote: > In its current form huge-pages through shmemfs are controlled at the > super-block level, and are currently disabled by default, so to enable > huge-pages for a shmem backed gem object we would need to re-mount the > fs with the huge= argument, but for drm the mount is not user visible, > so good luck with that. The other option is the global sysfs knob > shmem_enabled which exposes the same huge= options, with the addition of > DENY and FORCE. > > Neither option seems really workable, what we probably want is to able > to control the use of huge-pages at the time of pinning the backing > storage for a particular gem object, and only where it makes sense given > the size of the object. One caveat is when we write into the page cache > prior to pinning the backing storage. I played around with a bunch of > ideas but in the end just settled with driver overridable huge option > embedded in shmem_inode_info. Thoughts? > > Signed-off-by: Matthew Auld <matthew.auld@intel.com> You need to Cc: mm folks and mailing lists for this. Ask scripts/get_maintainers.pl for the full list please. Otherwise this can't ever land (and we're looking at along time of bikeshedding anyway). -Daniel > --- > include/linux/shmem_fs.h | 1 + > mm/shmem.c | 10 ++++++++-- > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h > index a7d6bd2a918f..001be751420d 100644 > --- a/include/linux/shmem_fs.h > +++ b/include/linux/shmem_fs.h > @@ -21,6 +21,7 @@ struct shmem_inode_info { > struct shared_policy policy; /* NUMA memory alloc policy */ > struct simple_xattrs xattrs; /* list of xattrs */ > struct inode vfs_inode; > + bool huge; /* driver override shmem_huge */ > }; > > struct shmem_sb_info { > diff --git a/mm/shmem.c b/mm/shmem.c > index e67d6ba4e98e..879a9e514afe 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1723,6 +1723,9 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, > /* shmem_symlink() */ > if (mapping->a_ops != &shmem_aops) > goto alloc_nohuge; > + /* driver override shmem_huge */ > + if (info->huge) > + goto alloc_huge; > if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE) > goto alloc_nohuge; > if (shmem_huge == SHMEM_HUGE_FORCE) > @@ -2000,6 +2003,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, > unsigned long inflated_len; > unsigned long inflated_addr; > unsigned long inflated_offset; > + struct shmem_inode_info *info = SHMEM_I(file_inode(file)); > > if (len > TASK_SIZE) > return -ENOMEM; > @@ -2016,7 +2020,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, > if (addr > TASK_SIZE - len) > return addr; > > - if (shmem_huge == SHMEM_HUGE_DENY) > + if (!info->huge && shmem_huge == SHMEM_HUGE_DENY) > return addr; > if (len < HPAGE_PMD_SIZE) > return addr; > @@ -2030,7 +2034,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, > if (uaddr) > return addr; > > - if (shmem_huge != SHMEM_HUGE_FORCE) { > + if (!info->huge && shmem_huge != SHMEM_HUGE_FORCE) { > struct super_block *sb; > > if (file) { > @@ -4034,6 +4038,8 @@ bool shmem_huge_enabled(struct vm_area_struct *vma) > loff_t i_size; > pgoff_t off; > > + if (SHMEM_I(inode)->huge) > + return true; > if (shmem_huge == SHMEM_HUGE_FORCE) > return true; > if (shmem_huge == SHMEM_HUGE_DENY) > -- > 2.9.3 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index a7d6bd2a918f..001be751420d 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -21,6 +21,7 @@ struct shmem_inode_info { struct shared_policy policy; /* NUMA memory alloc policy */ struct simple_xattrs xattrs; /* list of xattrs */ struct inode vfs_inode; + bool huge; /* driver override shmem_huge */ }; struct shmem_sb_info { diff --git a/mm/shmem.c b/mm/shmem.c index e67d6ba4e98e..879a9e514afe 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1723,6 +1723,9 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, /* shmem_symlink() */ if (mapping->a_ops != &shmem_aops) goto alloc_nohuge; + /* driver override shmem_huge */ + if (info->huge) + goto alloc_huge; if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE) goto alloc_nohuge; if (shmem_huge == SHMEM_HUGE_FORCE) @@ -2000,6 +2003,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, unsigned long inflated_len; unsigned long inflated_addr; unsigned long inflated_offset; + struct shmem_inode_info *info = SHMEM_I(file_inode(file)); if (len > TASK_SIZE) return -ENOMEM; @@ -2016,7 +2020,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, if (addr > TASK_SIZE - len) return addr; - if (shmem_huge == SHMEM_HUGE_DENY) + if (!info->huge && shmem_huge == SHMEM_HUGE_DENY) return addr; if (len < HPAGE_PMD_SIZE) return addr; @@ -2030,7 +2034,7 @@ unsigned long shmem_get_unmapped_area(struct file *file, if (uaddr) return addr; - if (shmem_huge != SHMEM_HUGE_FORCE) { + if (!info->huge && shmem_huge != SHMEM_HUGE_FORCE) { struct super_block *sb; if (file) { @@ -4034,6 +4038,8 @@ bool shmem_huge_enabled(struct vm_area_struct *vma) loff_t i_size; pgoff_t off; + if (SHMEM_I(inode)->huge) + return true; if (shmem_huge == SHMEM_HUGE_FORCE) return true; if (shmem_huge == SHMEM_HUGE_DENY)
In its current form huge-pages through shmemfs are controlled at the super-block level, and are currently disabled by default, so to enable huge-pages for a shmem backed gem object we would need to re-mount the fs with the huge= argument, but for drm the mount is not user visible, so good luck with that. The other option is the global sysfs knob shmem_enabled which exposes the same huge= options, with the addition of DENY and FORCE. Neither option seems really workable, what we probably want is to able to control the use of huge-pages at the time of pinning the backing storage for a particular gem object, and only where it makes sense given the size of the object. One caveat is when we write into the page cache prior to pinning the backing storage. I played around with a bunch of ideas but in the end just settled with driver overridable huge option embedded in shmem_inode_info. Thoughts? Signed-off-by: Matthew Auld <matthew.auld@intel.com> --- include/linux/shmem_fs.h | 1 + mm/shmem.c | 10 ++++++++-- 2 files changed, 9 insertions(+), 2 deletions(-)