| Message ID | ee1b6ac287bb376a9da88a23e1ef16951eb94a4e.1720755678.git.baolin.wang@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Some cleanups for shmem | expand |
On 13/07/2024 14:24, Baolin Wang wrote: > Move the suitable huge orders validation into shmem_suitable_orders() for > tmpfs, which can reuse some code to simplify the logic. > > In addition, we don't have special handling for the error code -E2BIG when > checking for conflicts with PMD sized THP in the pagecache for tmpfs, instead, > it will just fallback to order-0 allocations like this patch does, so this > simplification will not add functional changes. > > Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> > --- > mm/shmem.c | 39 +++++++++++++++------------------------ > 1 file changed, 15 insertions(+), 24 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index f24dfbd387ba..db7e9808830f 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1685,19 +1685,29 @@ static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault > struct address_space *mapping, pgoff_t index, > unsigned long orders) > { > - struct vm_area_struct *vma = vmf->vma; > + struct vm_area_struct *vma = vmf ? vmf->vma : NULL; > unsigned long pages; > int order; > > - orders = thp_vma_suitable_orders(vma, vmf->address, orders); > - if (!orders) > - return 0; > + if (vma) { > + orders = thp_vma_suitable_orders(vma, vmf->address, orders); > + if (!orders) > + return 0; > + } > > /* Find the highest order that can add into the page cache */ > order = highest_order(orders); > while (orders) { > pages = 1UL << order; > index = round_down(index, pages); > + /* > + * Check for conflict before waiting on a huge allocation. > + * Conflict might be that a huge page has just been allocated > + * and added to page cache by a racing thread, or that there > + * is already at least one small page in the huge extent. > + * Be careful to retry when appropriate, but not forever! > + * Elsewhere -EEXIST would be the right code, but not here. > + */ > if (!xa_find(&mapping->i_pages, &index, > index + pages - 1, XA_PRESENT)) > break; > @@ -1735,7 +1745,6 @@ static struct folio *shmem_alloc_and_add_folio(struct vm_fault *vmf, > { > struct address_space *mapping = inode->i_mapping; > struct shmem_inode_info *info = SHMEM_I(inode); > - struct vm_area_struct *vma = vmf ? vmf->vma : NULL; > unsigned long suitable_orders = 0; > struct folio *folio = NULL; > long pages; > @@ -1745,26 +1754,8 @@ static struct folio *shmem_alloc_and_add_folio(struct vm_fault *vmf, > orders = 0; > > if (orders > 0) { > - if (vma && vma_is_anon_shmem(vma)) { > - suitable_orders = shmem_suitable_orders(inode, vmf, > + suitable_orders = shmem_suitable_orders(inode, vmf, > mapping, index, orders); > - } else if (orders & BIT(HPAGE_PMD_ORDER)) { > - pages = HPAGE_PMD_NR; > - suitable_orders = BIT(HPAGE_PMD_ORDER); > - index = round_down(index, HPAGE_PMD_NR); > - > - /* > - * Check for conflict before waiting on a huge allocation. > - * Conflict might be that a huge page has just been allocated > - * and added to page cache by a racing thread, or that there > - * is already at least one small page in the huge extent. > - * Be careful to retry when appropriate, but not forever! > - * Elsewhere -EEXIST would be the right code, but not here. > - */ > - if (xa_find(&mapping->i_pages, &index, > - index + HPAGE_PMD_NR - 1, XA_PRESENT)) > - return ERR_PTR(-E2BIG); > - } > > order = highest_order(suitable_orders); > while (suitable_orders) {
On 13.07.24 15:24, Baolin Wang wrote: > Move the suitable huge orders validation into shmem_suitable_orders() for > tmpfs, which can reuse some code to simplify the logic. > > In addition, we don't have special handling for the error code -E2BIG when > checking for conflicts with PMD sized THP in the pagecache for tmpfs, instead, > it will just fallback to order-0 allocations like this patch does, so this > simplification will not add functional changes. > > Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> > --- Acked-by: David Hildenbrand <david@redhat.com>
diff --git a/mm/shmem.c b/mm/shmem.c index f24dfbd387ba..db7e9808830f 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1685,19 +1685,29 @@ static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault struct address_space *mapping, pgoff_t index, unsigned long orders) { - struct vm_area_struct *vma = vmf->vma; + struct vm_area_struct *vma = vmf ? vmf->vma : NULL; unsigned long pages; int order; - orders = thp_vma_suitable_orders(vma, vmf->address, orders); - if (!orders) - return 0; + if (vma) { + orders = thp_vma_suitable_orders(vma, vmf->address, orders); + if (!orders) + return 0; + } /* Find the highest order that can add into the page cache */ order = highest_order(orders); while (orders) { pages = 1UL << order; index = round_down(index, pages); + /* + * Check for conflict before waiting on a huge allocation. + * Conflict might be that a huge page has just been allocated + * and added to page cache by a racing thread, or that there + * is already at least one small page in the huge extent. + * Be careful to retry when appropriate, but not forever! + * Elsewhere -EEXIST would be the right code, but not here. + */ if (!xa_find(&mapping->i_pages, &index, index + pages - 1, XA_PRESENT)) break; @@ -1735,7 +1745,6 @@ static struct folio *shmem_alloc_and_add_folio(struct vm_fault *vmf, { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); - struct vm_area_struct *vma = vmf ? vmf->vma : NULL; unsigned long suitable_orders = 0; struct folio *folio = NULL; long pages; @@ -1745,26 +1754,8 @@ static struct folio *shmem_alloc_and_add_folio(struct vm_fault *vmf, orders = 0; if (orders > 0) { - if (vma && vma_is_anon_shmem(vma)) { - suitable_orders = shmem_suitable_orders(inode, vmf, + suitable_orders = shmem_suitable_orders(inode, vmf, mapping, index, orders); - } else if (orders & BIT(HPAGE_PMD_ORDER)) { - pages = HPAGE_PMD_NR; - suitable_orders = BIT(HPAGE_PMD_ORDER); - index = round_down(index, HPAGE_PMD_NR); - - /* - * Check for conflict before waiting on a huge allocation. - * Conflict might be that a huge page has just been allocated - * and added to page cache by a racing thread, or that there - * is already at least one small page in the huge extent. - * Be careful to retry when appropriate, but not forever! - * Elsewhere -EEXIST would be the right code, but not here. - */ - if (xa_find(&mapping->i_pages, &index, - index + HPAGE_PMD_NR - 1, XA_PRESENT)) - return ERR_PTR(-E2BIG); - } order = highest_order(suitable_orders); while (suitable_orders) {
Move the suitable huge orders validation into shmem_suitable_orders() for tmpfs, which can reuse some code to simplify the logic. In addition, we don't have special handling for the error code -E2BIG when checking for conflicts with PMD sized THP in the pagecache for tmpfs, instead, it will just fallback to order-0 allocations like this patch does, so this simplification will not add functional changes. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> --- mm/shmem.c | 39 +++++++++++++++------------------------ 1 file changed, 15 insertions(+), 24 deletions(-)