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Code Issues Releases Wiki Activity

mm/swap: avoid a xa load for swapout path 

A variable is never used for swapout path (shadowp is NULL) and compiler
is unable to optimize out the unneeded load since it's a function call.

The was introduced by 3852f6768e ("mm/swapcache: support to handle the
shadow entries").

Link: https://lkml.kernel.org/r/20231017011728.37508-1-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Kairui Song 2023-10-17 09:17:28 +08:00 committed by Andrew Morton
parent e56808fef8
commit e5b306a082
1 changed files with 3 additions and 3 deletions
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6
mm/swap_state.c
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@ -109,9 +109,9 @@ int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
goto unlock;
for (i = 0; i < nr; i++) {
VM_BUG_ON_FOLIO(xas.xa_index != idx + i, folio);
old = xas_load(&xas);
if (xa_is_value(old)) {
if (shadowp)
if (shadowp) {
old = xas_load(&xas);
if (xa_is_value(old))
*shadowp = old;
}
xas_store(&xas, folio);