| Message ID | d8e75079-af2d-8519-56df-6be1dccc247a@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: shmem: fix minor off-by-one in shrinkable calculation | expand |
On 26.08.24 00:42, Hugh Dickins wrote: > There has been a long-standing and very minor off-by-one, where > shmem_get_folio_gfp() decides if a large folio extends beyond i_size > far enough to leave a page or more for freeing later under pressure. > > This is not something needed for stable: but it will be proportionately > more significant as support for smaller large folios is added, and is > best fixed before duplicating the check in other places. > > Fixes: 779750d20b93 ("shmem: split huge pages beyond i_size under memory pressure") > Signed-off-by: Hugh Dickins <hughd@google.com> > --- > mm/shmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index 85e3bd3e709e..37c300f69baf 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -2326,7 +2326,7 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, > alloced = true; > if (folio_test_large(folio) && > DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < > - folio_next_index(folio) - 1) { > + folio_next_index(folio)) { > struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); > struct shmem_inode_info *info = SHMEM_I(inode); > /* Reviewed-by: David Hildenbrand <david@redhat.com>
On 2024/8/26 06:42, Hugh Dickins wrote: > There has been a long-standing and very minor off-by-one, where > shmem_get_folio_gfp() decides if a large folio extends beyond i_size > far enough to leave a page or more for freeing later under pressure. > > This is not something needed for stable: but it will be proportionately > more significant as support for smaller large folios is added, and is > best fixed before duplicating the check in other places. > > Fixes: 779750d20b93 ("shmem: split huge pages beyond i_size under memory pressure") > Signed-off-by: Hugh Dickins <hughd@google.com> LGTM. Feel free to add: Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> > --- > mm/shmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index 85e3bd3e709e..37c300f69baf 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -2326,7 +2326,7 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, > alloced = true; > if (folio_test_large(folio) && > DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < > - folio_next_index(folio) - 1) { > + folio_next_index(folio)) { > struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); > struct shmem_inode_info *info = SHMEM_I(inode); > /*
diff --git a/mm/shmem.c b/mm/shmem.c index 85e3bd3e709e..37c300f69baf 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2326,7 +2326,7 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, alloced = true; if (folio_test_large(folio) && DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < - folio_next_index(folio) - 1) { + folio_next_index(folio)) { struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); struct shmem_inode_info *info = SHMEM_I(inode); /*
There has been a long-standing and very minor off-by-one, where shmem_get_folio_gfp() decides if a large folio extends beyond i_size far enough to leave a page or more for freeing later under pressure. This is not something needed for stable: but it will be proportionately more significant as support for smaller large folios is added, and is best fixed before duplicating the check in other places. Fixes: 779750d20b93 ("shmem: split huge pages beyond i_size under memory pressure") Signed-off-by: Hugh Dickins <hughd@google.com> --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)