admin/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2025-12-07 20:06:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

mm/huge_memory: update folio stat after successful split

Browse Source 
The current implementation complicates this process:

  * It iterates over the resulting new folios.
  * It uses a flag (@stop_split) to conditionally skip updating the stat
    for the folio at @split_at during the loop.
  * It then attempts to update the skipped stat on a subsequent failure
    path.

This logic is unnecessarily hard to follow.

This commit refactors the code to update the folio statistics only after a
successful split.  This makes the logic much cleaner and sets the stage
for further simplification of the stat-handling code.

Link: https://lkml.kernel.org/r/20251021212142.25766-3-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: wang lian <lianux.mm@gmail.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.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>
This commit is contained in:
Wei Yang
2025-10-21 21:21:40 +00:00
committed by Andrew Morton
parent ef0258857d
commit 092ef38997
1 changed files with 11 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

44
mm/huge_memory.c
View File

@@ -3404,20 +3404,15 @@ static int __split_unmapped_folio(struct folio *folio, int new_order,
const bool is_anon = folio_test_anon(folio);
int order = folio_order(folio);
int start_order = uniform_split ? new_order : order - 1;
bool stop_split = false;
struct folio *next;
int split_order;
int ret = 0;
if (is_anon)
mod_mthp_stat(order, MTHP_STAT_NR_ANON, -1);
/*
* split to new_order one order at a time. For uniform split,
* folio is split to new_order directly.
*/
for (split_order = start_order;
split_order >= new_order && !stop_split;
split_order >= new_order;
split_order--) {
struct folio *end_folio = folio_next(folio);
int old_order = folio_order(folio);
@@ -3440,49 +3435,32 @@ static int __split_unmapped_folio(struct folio *folio, int new_order,
else {
xas_set_order(xas, folio->index, split_order);
xas_try_split(xas, folio, old_order);
if (xas_error(xas)) {
ret = xas_error(xas);
stop_split = true;
}
if (xas_error(xas))
return xas_error(xas);
}
}
if (!stop_split) {
folio_split_memcg_refs(folio, old_order, split_order);
split_page_owner(&folio->page, old_order, split_order);
pgalloc_tag_split(folio, old_order, split_order);
__split_folio_to_order(folio, old_order, split_order);
}
folio_split_memcg_refs(folio, old_order, split_order);
split_page_owner(&folio->page, old_order, split_order);
pgalloc_tag_split(folio, old_order, split_order);
__split_folio_to_order(folio, old_order, split_order);
if (is_anon)
mod_mthp_stat(old_order, MTHP_STAT_NR_ANON, -1);
/*
* Iterate through after-split folios and update folio stats.
* But in buddy allocator like split, the folio
* containing the specified page is skipped until its order
* is new_order, since the folio will be worked on in next
* iteration.
*/
for (new_folio = folio; new_folio != end_folio; new_folio = next) {
next = folio_next(new_folio);
/*
* for buddy allocator like split, new_folio containing
* @split_at page could be split again, thus do not
* change stats yet. Wait until new_folio's order is
* @new_order or stop_split is set to true by the above
* xas_split() failure.
*/
if (new_folio == page_folio(split_at)) {
if (new_folio == page_folio(split_at))
folio = new_folio;
if (split_order != new_order && !stop_split)
continue;
}
if (is_anon)
mod_mthp_stat(folio_order(new_folio),
MTHP_STAT_NR_ANON, 1);
}
}
return ret;
return 0;
}
bool non_uniform_split_supported(struct folio *folio, unsigned int new_order,