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Date: Fri, 17 May 2024 09:17:41 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: Daniel Gomez <da.gomez@...sung.com>
Cc: "hughd@...gle.com" <hughd@...gle.com>,
"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
"willy@...radead.org" <willy@...radead.org>,
"jack@...e.cz" <jack@...e.cz>,
"mcgrof@...nel.org" <mcgrof@...nel.org>,
"linux-mm@...ck.org" <linux-mm@...ck.org>,
"linux-xfs@...r.kernel.org" <linux-xfs@...r.kernel.org>,
Pankaj Raghav <p.raghav@...sung.com>,
"dagmcr@...il.com" <dagmcr@...il.com>,
"yosryahmed@...gle.com" <yosryahmed@...gle.com>,
"baolin.wang@...ux.alibaba.com" <baolin.wang@...ux.alibaba.com>,
"ritesh.list@...il.com" <ritesh.list@...il.com>,
"lsf-pc@...ts.linux-foundation.org" <lsf-pc@...ts.linux-foundation.org>,
"david@...hat.com" <david@...hat.com>,
"chandan.babu@...cle.com" <chandan.babu@...cle.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"brauner@...nel.org" <brauner@...nel.org>
Subject: Re: [PATCH 11/12] shmem: add file length arg in shmem_get_folio()
path
On Wed, May 15, 2024 at 05:57:36AM +0000, Daniel Gomez wrote:
> In preparation for large folio in the write and fallocate paths, add
> file length argument in shmem_get_folio() path to be able to calculate
> the folio order based on the file size. Use of order-0 (PAGE_SIZE) for
> read, page cache read, and vm fault.
>
> This enables high order folios in the write and fallocate path once the
> folio order is calculated based on the length.
>
> Signed-off-by: Daniel Gomez <da.gomez@...sung.com>
> ---
> fs/xfs/scrub/xfile.c | 6 +++---
> fs/xfs/xfs_buf_mem.c | 3 ++-
> include/linux/shmem_fs.h | 2 +-
> mm/khugepaged.c | 3 ++-
> mm/shmem.c | 35 ++++++++++++++++++++---------------
> mm/userfaultfd.c | 2 +-
> 6 files changed, 29 insertions(+), 22 deletions(-)
>
> diff --git a/fs/xfs/scrub/xfile.c b/fs/xfs/scrub/xfile.c
> index 8cdd863db585..4905f5e4cb5d 100644
> --- a/fs/xfs/scrub/xfile.c
> +++ b/fs/xfs/scrub/xfile.c
> @@ -127,7 +127,7 @@ xfile_load(
> unsigned int offset;
>
> if (shmem_get_folio(inode, pos >> PAGE_SHIFT, &folio,
> - SGP_READ) < 0)
> + SGP_READ, PAGE_SIZE) < 0)
I suppose I /did/ say during LSFMM that for the current users of xfile.c
and xfs_buf_mem.c the order of the folio being returned doesn't really
matter, but why wouldn't the last argument here be "roundup_64(count,
PAGE_SIZE)" ? Shouldn't we at least hint to the page cache about the
folio order that we actually want instead of limiting it to order-0?
(Also it seems a little odd to me that the @index is in units of pgoff_t
but @len is in bytes.)
> break;
> if (!folio) {
> /*
> @@ -197,7 +197,7 @@ xfile_store(
> unsigned int offset;
>
> if (shmem_get_folio(inode, pos >> PAGE_SHIFT, &folio,
> - SGP_CACHE) < 0)
> + SGP_CACHE, PAGE_SIZE) < 0)
> break;
> if (filemap_check_wb_err(inode->i_mapping, 0)) {
> folio_unlock(folio);
> @@ -268,7 +268,7 @@ xfile_get_folio(
>
> pflags = memalloc_nofs_save();
> error = shmem_get_folio(inode, pos >> PAGE_SHIFT, &folio,
> - (flags & XFILE_ALLOC) ? SGP_CACHE : SGP_READ);
> + (flags & XFILE_ALLOC) ? SGP_CACHE : SGP_READ, PAGE_SIZE);
> memalloc_nofs_restore(pflags);
> if (error)
> return ERR_PTR(error);
> diff --git a/fs/xfs/xfs_buf_mem.c b/fs/xfs/xfs_buf_mem.c
> index 9bb2d24de709..784c81d35a1f 100644
> --- a/fs/xfs/xfs_buf_mem.c
> +++ b/fs/xfs/xfs_buf_mem.c
> @@ -149,7 +149,8 @@ xmbuf_map_page(
> return -ENOMEM;
> }
>
> - error = shmem_get_folio(inode, pos >> PAGE_SHIFT, &folio, SGP_CACHE);
> + error = shmem_get_folio(inode, pos >> PAGE_SHIFT, &folio, SGP_CACHE,
> + PAGE_SIZE);
This is ok unless someone wants to use a different XMBUF_BLOCKSIZE.
--D
> if (error)
> return error;
>
> diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
> index 3fb18f7eb73e..bc59b4a00228 100644
> --- a/include/linux/shmem_fs.h
> +++ b/include/linux/shmem_fs.h
> @@ -142,7 +142,7 @@ enum sgp_type {
> };
>
> int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
> - enum sgp_type sgp);
> + enum sgp_type sgp, size_t len);
> struct folio *shmem_read_folio_gfp(struct address_space *mapping,
> pgoff_t index, gfp_t gfp);
>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 38830174608f..947770ded68c 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -1863,7 +1863,8 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
> xas_unlock_irq(&xas);
> /* swap in or instantiate fallocated page */
> if (shmem_get_folio(mapping->host, index,
> - &folio, SGP_NOALLOC)) {
> + &folio, SGP_NOALLOC,
> + PAGE_SIZE)) {
> result = SCAN_FAIL;
> goto xa_unlocked;
> }
> diff --git a/mm/shmem.c b/mm/shmem.c
> index d531018ffece..fcd2c9befe19 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -1134,7 +1134,7 @@ static struct folio *shmem_get_partial_folio(struct inode *inode, pgoff_t index)
> * (although in some cases this is just a waste of time).
> */
> folio = NULL;
> - shmem_get_folio(inode, index, &folio, SGP_READ);
> + shmem_get_folio(inode, index, &folio, SGP_READ, PAGE_SIZE);
> return folio;
> }
>
> @@ -1844,7 +1844,7 @@ static struct folio *shmem_alloc_folio(gfp_t gfp, struct shmem_inode_info *info,
>
> static struct folio *shmem_alloc_and_add_folio(gfp_t gfp,
> struct inode *inode, pgoff_t index,
> - struct mm_struct *fault_mm, bool huge)
> + struct mm_struct *fault_mm, bool huge, size_t len)
> {
> struct address_space *mapping = inode->i_mapping;
> struct shmem_inode_info *info = SHMEM_I(inode);
> @@ -2173,7 +2173,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
> */
> static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index,
> struct folio **foliop, enum sgp_type sgp, gfp_t gfp,
> - struct vm_fault *vmf, vm_fault_t *fault_type)
> + struct vm_fault *vmf, vm_fault_t *fault_type, size_t len)
> {
> struct vm_area_struct *vma = vmf ? vmf->vma : NULL;
> struct mm_struct *fault_mm;
> @@ -2258,7 +2258,7 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index,
> huge_gfp = vma_thp_gfp_mask(vma);
> huge_gfp = limit_gfp_mask(huge_gfp, gfp);
> folio = shmem_alloc_and_add_folio(huge_gfp,
> - inode, index, fault_mm, true);
> + inode, index, fault_mm, true, len);
> if (!IS_ERR(folio)) {
> count_vm_event(THP_FILE_ALLOC);
> goto alloced;
> @@ -2267,7 +2267,8 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index,
> goto repeat;
> }
>
> - folio = shmem_alloc_and_add_folio(gfp, inode, index, fault_mm, false);
> + folio = shmem_alloc_and_add_folio(gfp, inode, index, fault_mm, false,
> + len);
> if (IS_ERR(folio)) {
> error = PTR_ERR(folio);
> if (error == -EEXIST)
> @@ -2377,10 +2378,10 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index,
> * Return: 0 if successful, else a negative error code.
> */
> int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
> - enum sgp_type sgp)
> + enum sgp_type sgp, size_t len)
> {
> return shmem_get_folio_gfp(inode, index, foliop, sgp,
> - mapping_gfp_mask(inode->i_mapping), NULL, NULL);
> + mapping_gfp_mask(inode->i_mapping), NULL, NULL, len);
> }
> EXPORT_SYMBOL_GPL(shmem_get_folio);
>
> @@ -2475,7 +2476,7 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf)
>
> WARN_ON_ONCE(vmf->page != NULL);
> err = shmem_get_folio_gfp(inode, vmf->pgoff, &folio, SGP_CACHE,
> - gfp, vmf, &ret);
> + gfp, vmf, &ret, PAGE_SIZE);
> if (err)
> return vmf_error(err);
> if (folio) {
> @@ -2954,6 +2955,9 @@ shmem_write_begin(struct file *file, struct address_space *mapping,
> struct folio *folio;
> int ret = 0;
>
> + if (!mapping_large_folio_support(mapping))
> + len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos));
> +
> /* i_rwsem is held by caller */
> if (unlikely(info->seals & (F_SEAL_GROW |
> F_SEAL_WRITE | F_SEAL_FUTURE_WRITE))) {
> @@ -2963,7 +2967,7 @@ shmem_write_begin(struct file *file, struct address_space *mapping,
> return -EPERM;
> }
>
> - ret = shmem_get_folio(inode, index, &folio, SGP_WRITE);
> + ret = shmem_get_folio(inode, index, &folio, SGP_WRITE, len);
> if (ret)
> return ret;
>
> @@ -3083,7 +3087,7 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> break;
> }
>
> - error = shmem_get_folio(inode, index, &folio, SGP_READ);
> + error = shmem_get_folio(inode, index, &folio, SGP_READ, PAGE_SIZE);
> if (error) {
> if (error == -EINVAL)
> error = 0;
> @@ -3260,7 +3264,7 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
> break;
>
> error = shmem_get_folio(inode, *ppos / PAGE_SIZE, &folio,
> - SGP_READ);
> + SGP_READ, PAGE_SIZE);
> if (error) {
> if (error == -EINVAL)
> error = 0;
> @@ -3469,7 +3473,8 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
> error = -ENOMEM;
> else
> error = shmem_get_folio(inode, index, &folio,
> - SGP_FALLOC);
> + SGP_FALLOC,
> + (end - index) << PAGE_SHIFT);
> if (error) {
> info->fallocend = undo_fallocend;
> /* Remove the !uptodate folios we added */
> @@ -3822,7 +3827,7 @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir,
> } else {
> inode_nohighmem(inode);
> inode->i_mapping->a_ops = &shmem_aops;
> - error = shmem_get_folio(inode, 0, &folio, SGP_WRITE);
> + error = shmem_get_folio(inode, 0, &folio, SGP_WRITE, PAGE_SIZE);
> if (error)
> goto out_remove_offset;
> inode->i_op = &shmem_symlink_inode_operations;
> @@ -3868,7 +3873,7 @@ static const char *shmem_get_link(struct dentry *dentry, struct inode *inode,
> return ERR_PTR(-ECHILD);
> }
> } else {
> - error = shmem_get_folio(inode, 0, &folio, SGP_READ);
> + error = shmem_get_folio(inode, 0, &folio, SGP_READ, PAGE_SIZE);
> if (error)
> return ERR_PTR(error);
> if (!folio)
> @@ -5255,7 +5260,7 @@ struct folio *shmem_read_folio_gfp(struct address_space *mapping,
> int error;
>
> error = shmem_get_folio_gfp(inode, index, &folio, SGP_CACHE,
> - gfp, NULL, NULL);
> + gfp, NULL, NULL, PAGE_SIZE);
> if (error)
> return ERR_PTR(error);
>
> diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
> index 3c3539c573e7..540a0c2d4325 100644
> --- a/mm/userfaultfd.c
> +++ b/mm/userfaultfd.c
> @@ -359,7 +359,7 @@ static int mfill_atomic_pte_continue(pmd_t *dst_pmd,
> struct page *page;
> int ret;
>
> - ret = shmem_get_folio(inode, pgoff, &folio, SGP_NOALLOC);
> + ret = shmem_get_folio(inode, pgoff, &folio, SGP_NOALLOC, PAGE_SIZE);
> /* Our caller expects us to return -EFAULT if we failed to find folio */
> if (ret == -ENOENT)
> ret = -EFAULT;
> --
> 2.43.0
>
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