diff options
| author | Wei Yang <richard.weiyang@gmail.com> | 2025-10-21 21:21:42 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-11-16 17:28:19 -0800 |
| commit | f0b1602871f8506c5aa704e9641b004f21918759 (patch) | |
| tree | 749be8acdcfbf1f4b39a482ce582628c595f99ae /mm/huge_memory.c | |
| parent | fc4f15ee0bcd56f40ad1df723ac9889d7e82f5a0 (diff) | |
mm/huge_memory: optimize old_order derivation during folio splitting
Folio splitting requires both the folio's original order (@old_order) and
the new target order (@split_order).
In the current implementation, @old_order is repeatedly retrieved using
folio_order().
However, for every iteration after the first, the folio being split is the
result of the previous split, meaning its order is already known to be
equal to the previous iteration's @split_order.
This commit optimizes the logic:
* Instead of calling folio_order(), we now set @old_order directly to
the value of @split_order from the previous iteration.
This change avoids unnecessary function calls and simplifies the loop
setup.
Also it removes a check for non-existent case, since for uniform splitting
we only do split when @split_order == @new_order.
Link: https://lkml.kernel.org/r/20251021212142.25766-5-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: wang lian <lianux.mm@gmail.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 52c4114a17f2..0a521cf9b10a 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3402,8 +3402,8 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, struct address_space *mapping, bool uniform_split) { const bool is_anon = folio_test_anon(folio); - int order = folio_order(folio); - int start_order = uniform_split ? new_order : order - 1; + int old_order = folio_order(folio); + int start_order = uniform_split ? new_order : old_order - 1; int split_order; /* @@ -3413,14 +3413,11 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, for (split_order = start_order; split_order >= new_order; split_order--) { - int old_order = folio_order(folio); int nr_new_folios = 1UL << (old_order - split_order); /* order-1 anonymous folio is not supported */ if (is_anon && split_order == 1) continue; - if (uniform_split && split_order != new_order) - continue; if (mapping) { /* @@ -3447,7 +3444,13 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, mod_mthp_stat(old_order, MTHP_STAT_NR_ANON, -1); mod_mthp_stat(split_order, MTHP_STAT_NR_ANON, nr_new_folios); } + /* + * If uniform split, the process is complete. + * If non-uniform, continue splitting the folio at @split_at + * as long as the next @split_order is >= @new_order. + */ folio = page_folio(split_at); + old_order = split_order; } return 0; |