mm: reduce deferred struct page init ifdeffery

Patch series "mm: Fix several issues with unaccepted memory", v2.

The patchset addresses several issues related to unaccepted memory.

Pacth 1/7 preparatory cleanup.

Patch 2/7 ensures that __alloc_pages_bulk() will not exhaust all
accepted memory without accepting more.

Patches 3/7-5/7 are preparations for patch 6/7, which fixes
alloc_config_page() on machines with unaccepted memory.  This allows, for
example, the allocation of gigantic pages at runtime.

Patch 7/7 enables the kernel to accept memory up to the promo watermark.

This patch (of 7):

Add dummy _deferred_grow_zone() for !DEFERRED_STRUCT_PAGE_INIT and remove
#ifdefs in two places.

No functional changes.

Link: https://lkml.kernel.org/r/20240809114854.3745464-1-kirill.shutemov@linux.intel.com
Link: https://lkml.kernel.org/r/20240809114854.3745464-3-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 60742d057b0583a4a5edbd736d1937e8a47a722f..006cab0d2f2fc149af0c35c9d14f0be130f90e23 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -322,6 +322,11 @@ static inline bool deferred_pages_enabled(void)
 {
        return false;
 }
+
+static inline bool _deferred_grow_zone(struct zone *zone, unsigned int order)
+{
+       return false;
+}
 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
 
 /* Return a pointer to the bitmap storing bits affecting a block of pages */
@@ -3395,7 +3400,6 @@ check_alloc_wmark:
                        if (cond_accept_memory(zone, order))
                                goto try_this_zone;
 
-#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
                        /*
                         * Watermark failed for this zone, but see if we can
                         * grow this zone if it contains deferred pages.
@@ -3404,7 +3408,6 @@ check_alloc_wmark:
                                if (_deferred_grow_zone(zone, order))
                                        goto try_this_zone;
                        }
-#endif
                        /* Checked here to keep the fast path fast */
                        BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
                        if (alloc_flags & ALLOC_NO_WATERMARKS)
@@ -3450,13 +3453,11 @@ try_this_zone:
                        if (cond_accept_memory(zone, order))
                                goto try_this_zone;
 
-#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
                        /* Try again if zone has deferred pages */
                        if (deferred_pages_enabled()) {
                                if (_deferred_grow_zone(zone, order))
                                        goto try_this_zone;
                        }
-#endif
                }
        }