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Message-ID: <20250113093453.1932083-9-kirill.shutemov@linux.intel.com>
Date: Mon, 13 Jan 2025 11:34:53 +0200
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
"Matthew Wilcox (Oracle)" <willy@...radead.org>,
Jens Axboe <axboe@...nel.dk>
Cc: "Jason A. Donenfeld" <Jason@...c4.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Andi Shyti <andi.shyti@...ux.intel.com>,
Chengming Zhou <chengming.zhou@...ux.dev>,
Christian Brauner <brauner@...nel.org>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Dan Carpenter <dan.carpenter@...aro.org>,
David Airlie <airlied@...il.com>,
David Hildenbrand <david@...hat.com>,
Hao Ge <gehao@...inos.cn>,
Jani Nikula <jani.nikula@...ux.intel.com>,
Johannes Weiner <hannes@...xchg.org>,
Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
Josef Bacik <josef@...icpanda.com>,
Masami Hiramatsu <mhiramat@...nel.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Miklos Szeredi <miklos@...redi.hu>,
Nhat Pham <nphamcs@...il.com>,
Oscar Salvador <osalvador@...e.de>,
Ran Xiaokai <ran.xiaokai@....com.cn>,
Rodrigo Vivi <rodrigo.vivi@...el.com>,
Simona Vetter <simona@...ll.ch>,
Steven Rostedt <rostedt@...dmis.org>,
Tvrtko Ursulin <tursulin@...ulin.net>,
Vlastimil Babka <vbabka@...e.cz>,
Yosry Ahmed <yosryahmed@...gle.com>,
Yu Zhao <yuzhao@...gle.com>,
intel-gfx@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org,
linux-kernel@...r.kernel.org,
linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org,
linux-trace-kernel@...r.kernel.org
Subject: [PATCH 8/8] mm: Remove PG_reclaim
Nobody sets the flag anymore.
Remove the PG_reclaim, making PG_readhead exclusive user of the page
flag bit.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
fs/fuse/dev.c | 2 +-
fs/proc/page.c | 2 +-
include/linux/mm_inline.h | 1 -
include/linux/page-flags.h | 15 +++++----------
include/trace/events/mmflags.h | 2 +-
include/uapi/linux/kernel-page-flags.h | 2 +-
mm/filemap.c | 12 ------------
mm/migrate.c | 10 ++--------
mm/page-writeback.c | 16 +---------------
mm/page_io.c | 15 +++++----------
mm/swap.c | 16 ----------------
mm/vmscan.c | 7 -------
tools/mm/page-types.c | 8 +-------
13 files changed, 18 insertions(+), 90 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 27ccae63495d..20005e2e1d28 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -827,7 +827,7 @@ static int fuse_check_folio(struct folio *folio)
1 << PG_lru |
1 << PG_active |
1 << PG_workingset |
- 1 << PG_reclaim |
+ 1 << PG_readahead |
1 << PG_waiters |
LRU_GEN_MASK | LRU_REFS_MASK))) {
dump_page(&folio->page, "fuse: trying to steal weird page");
diff --git a/fs/proc/page.c b/fs/proc/page.c
index a55f5acefa97..59860ba2393c 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -189,7 +189,7 @@ u64 stable_page_flags(const struct page *page)
u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
- u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
+ u |= kpf_copy_bit(k, KPF_READAHEAD, PG_readahead);
#define SWAPCACHE ((1 << PG_swapbacked) | (1 << PG_swapcache))
if ((k & SWAPCACHE) == SWAPCACHE)
diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index f353d3c610ac..269acf1f77b4 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -270,7 +270,6 @@ static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio,
set_mask_bits(&folio->flags, LRU_GEN_MASK | BIT(PG_active), flags);
lru_gen_update_size(lruvec, folio, -1, gen);
- /* for folio_rotate_reclaimable() */
if (reclaiming)
list_add_tail(&folio->lru, &lrugen->folios[gen][type][zone]);
else
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 2414e7921eea..8f59fd8b86c9 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -63,8 +63,8 @@
* might lose their PG_swapbacked flag when they simply can be dropped (e.g. as
* a result of MADV_FREE).
*
- * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
- * file-backed pagecache (see mm/vmscan.c).
+ * PG_referenced is used for page reclaim for anonymous and file-backed
+ * pagecache (see mm/vmscan.c).
*
* PG_arch_1 is an architecture specific page state bit. The generic code
* guarantees that this bit is cleared for a page when it first is entered into
@@ -107,7 +107,7 @@ enum pageflags {
PG_reserved,
PG_private, /* If pagecache, has fs-private data */
PG_private_2, /* If pagecache, has fs aux data */
- PG_reclaim, /* To be reclaimed asap */
+ PG_readahead,
PG_swapbacked, /* Page is backed by RAM/swap */
PG_unevictable, /* Page is "unevictable" */
PG_dropbehind, /* drop pages on IO completion */
@@ -129,8 +129,6 @@ enum pageflags {
#endif
__NR_PAGEFLAGS,
- PG_readahead = PG_reclaim,
-
/* Anonymous memory (and shmem) */
PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */
/* Some filesystems */
@@ -168,7 +166,7 @@ enum pageflags {
PG_xen_remapped = PG_owner_priv_1,
/* non-lru isolated movable page */
- PG_isolated = PG_reclaim,
+ PG_isolated = PG_readahead,
/* Only valid for buddy pages. Used to track pages that are reported */
PG_reported = PG_uptodate,
@@ -187,7 +185,7 @@ enum pageflags {
/* At least one page in this folio has the hwpoison flag set */
PG_has_hwpoisoned = PG_active,
PG_large_rmappable = PG_workingset, /* anon or file-backed */
- PG_partially_mapped = PG_reclaim, /* was identified to be partially mapped */
+ PG_partially_mapped = PG_readahead, /* was identified to be partially mapped */
};
#define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1)
@@ -594,9 +592,6 @@ TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
FOLIO_FLAG(mappedtodisk, FOLIO_HEAD_PAGE)
-/* PG_readahead is only used for reads; PG_reclaim is only for writes */
-PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
- TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
FOLIO_FLAG(readahead, FOLIO_HEAD_PAGE)
FOLIO_TEST_CLEAR_FLAG(readahead, FOLIO_HEAD_PAGE)
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 3bc8656c8359..15d92784a745 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -114,7 +114,7 @@
DEF_PAGEFLAG_NAME(private_2), \
DEF_PAGEFLAG_NAME(writeback), \
DEF_PAGEFLAG_NAME(head), \
- DEF_PAGEFLAG_NAME(reclaim), \
+ DEF_PAGEFLAG_NAME(readahead), \
DEF_PAGEFLAG_NAME(swapbacked), \
DEF_PAGEFLAG_NAME(unevictable), \
DEF_PAGEFLAG_NAME(dropbehind) \
diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h
index ff8032227876..e5a9a113e079 100644
--- a/include/uapi/linux/kernel-page-flags.h
+++ b/include/uapi/linux/kernel-page-flags.h
@@ -15,7 +15,7 @@
#define KPF_ACTIVE 6
#define KPF_SLAB 7
#define KPF_WRITEBACK 8
-#define KPF_RECLAIM 9
+#define KPF_READAHEAD 9
#define KPF_BUDDY 10
/* 11-20: new additions in 2.6.31 */
diff --git a/mm/filemap.c b/mm/filemap.c
index 5ca26f5e7238..8951c37c8a38 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1624,18 +1624,6 @@ void folio_end_writeback(struct folio *folio)
VM_BUG_ON_FOLIO(!folio_test_writeback(folio), folio);
- /*
- * folio_test_clear_reclaim() could be used here but it is an
- * atomic operation and overkill in this particular case. Failing
- * to shuffle a folio marked for immediate reclaim is too mild
- * a gain to justify taking an atomic operation penalty at the
- * end of every folio writeback.
- */
- if (folio_test_reclaim(folio)) {
- folio_clear_reclaim(folio);
- folio_rotate_reclaimable(folio);
- }
-
/*
* Writeback does not hold a folio reference of its own, relying
* on truncation to wait for the clearing of PG_writeback.
diff --git a/mm/migrate.c b/mm/migrate.c
index caadbe393aa2..beba72da5e33 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -686,6 +686,8 @@ void folio_migrate_flags(struct folio *newfolio, struct folio *folio)
folio_set_young(newfolio);
if (folio_test_idle(folio))
folio_set_idle(newfolio);
+ if (folio_test_readahead(folio))
+ folio_set_readahead(newfolio);
folio_migrate_refs(newfolio, folio);
/*
@@ -728,14 +730,6 @@ void folio_migrate_flags(struct folio *newfolio, struct folio *folio)
if (folio_test_writeback(newfolio))
folio_end_writeback(newfolio);
- /*
- * PG_readahead shares the same bit with PG_reclaim. The above
- * end_page_writeback() may clear PG_readahead mistakenly, so set the
- * bit after that.
- */
- if (folio_test_readahead(folio))
- folio_set_readahead(newfolio);
-
folio_copy_owner(newfolio, folio);
pgalloc_tag_swap(newfolio, folio);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 4f5970723cf2..f2b94a2cbfcf 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2888,22 +2888,8 @@ bool folio_mark_dirty(struct folio *folio)
{
struct address_space *mapping = folio_mapping(folio);
- if (likely(mapping)) {
- /*
- * readahead/folio_deactivate could remain
- * PG_readahead/PG_reclaim due to race with folio_end_writeback
- * About readahead, if the folio is written, the flags would be
- * reset. So no problem.
- * About folio_deactivate, if the folio is redirtied,
- * the flag will be reset. So no problem. but if the
- * folio is used by readahead it will confuse readahead
- * and make it restart the size rampup process. But it's
- * a trivial problem.
- */
- if (folio_test_reclaim(folio))
- folio_clear_reclaim(folio);
+ if (likely(mapping))
return mapping->a_ops->dirty_folio(mapping, folio);
- }
return noop_dirty_folio(mapping, folio);
}
diff --git a/mm/page_io.c b/mm/page_io.c
index 9b983de351f9..0cb71f318fb1 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -37,14 +37,11 @@ static void __end_swap_bio_write(struct bio *bio)
* Re-dirty the page in order to avoid it being reclaimed.
* Also print a dire warning that things will go BAD (tm)
* very quickly.
- *
- * Also clear PG_reclaim to avoid folio_rotate_reclaimable()
*/
folio_mark_dirty(folio);
pr_alert_ratelimited("Write-error on swap-device (%u:%u:%llu)\n",
MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
(unsigned long long)bio->bi_iter.bi_sector);
- folio_clear_reclaim(folio);
}
folio_end_writeback(folio);
}
@@ -350,19 +347,17 @@ static void sio_write_complete(struct kiocb *iocb, long ret)
if (ret != sio->len) {
/*
- * In the case of swap-over-nfs, this can be a
- * temporary failure if the system has limited
- * memory for allocating transmit buffers.
- * Mark the page dirty and avoid
- * folio_rotate_reclaimable but rate-limit the
- * messages.
+ * In the case of swap-over-nfs, this can be a temporary failure
+ * if the system has limited memory for allocating transmit
+ * buffers.
+ *
+ * Mark the page dirty but rate-limit the messages.
*/
pr_err_ratelimited("Write error %ld on dio swapfile (%llu)\n",
ret, swap_dev_pos(page_swap_entry(page)));
for (p = 0; p < sio->pages; p++) {
page = sio->bvec[p].bv_page;
set_page_dirty(page);
- ClearPageReclaim(page);
}
}
diff --git a/mm/swap.c b/mm/swap.c
index 4eb33b4804a8..5b94f13821e3 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -221,22 +221,6 @@ static void lru_move_tail(struct lruvec *lruvec, struct folio *folio)
__count_vm_events(PGROTATED, folio_nr_pages(folio));
}
-/*
- * Writeback is about to end against a folio which has been marked for
- * immediate reclaim. If it still appears to be reclaimable, move it
- * to the tail of the inactive list.
- *
- * folio_rotate_reclaimable() must disable IRQs, to prevent nasty races.
- */
-void folio_rotate_reclaimable(struct folio *folio)
-{
- if (folio_test_locked(folio) || folio_test_dirty(folio) ||
- folio_test_unevictable(folio))
- return;
-
- folio_batch_add_and_move(folio, lru_move_tail, true);
-}
-
void lru_note_cost(struct lruvec *lruvec, bool file,
unsigned int nr_io, unsigned int nr_rotated)
{
diff --git a/mm/vmscan.c b/mm/vmscan.c
index bb5ec22f97b5..e61e88e63511 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3216,9 +3216,6 @@ static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclai
new_flags = old_flags & ~(LRU_GEN_MASK | LRU_REFS_FLAGS);
new_flags |= (new_gen + 1UL) << LRU_GEN_PGOFF;
- /* for folio_end_writeback() */
- if (reclaiming)
- new_flags |= BIT(PG_reclaim);
} while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));
lru_gen_update_size(lruvec, folio, old_gen, new_gen);
@@ -4460,9 +4457,6 @@ static bool isolate_folio(struct lruvec *lruvec, struct folio *folio, struct sca
if (!folio_test_referenced(folio))
set_mask_bits(&folio->flags, LRU_REFS_MASK, 0);
- /* for shrink_folio_list() */
- folio_clear_reclaim(folio);
-
success = lru_gen_del_folio(lruvec, folio, true);
VM_WARN_ON_ONCE_FOLIO(!success, folio);
@@ -4659,7 +4653,6 @@ static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap
continue;
}
- /* retry folios that may have missed folio_rotate_reclaimable() */
if (!skip_retry && !folio_test_active(folio) && !folio_mapped(folio) &&
!folio_test_dirty(folio) && !folio_test_writeback(folio)) {
list_move(&folio->lru, &clean);
diff --git a/tools/mm/page-types.c b/tools/mm/page-types.c
index bcac7ebfb51f..c06647501370 100644
--- a/tools/mm/page-types.c
+++ b/tools/mm/page-types.c
@@ -85,7 +85,6 @@
* not part of kernel API
*/
#define KPF_ANON_EXCLUSIVE 47
-#define KPF_READAHEAD 48
#define KPF_SLUB_FROZEN 50
#define KPF_SLUB_DEBUG 51
#define KPF_FILE 61
@@ -108,7 +107,7 @@ static const char * const page_flag_names[] = {
[KPF_ACTIVE] = "A:active",
[KPF_SLAB] = "S:slab",
[KPF_WRITEBACK] = "W:writeback",
- [KPF_RECLAIM] = "I:reclaim",
+ [KPF_READAHEAD] = "I:readahead",
[KPF_BUDDY] = "B:buddy",
[KPF_MMAP] = "M:mmap",
@@ -139,7 +138,6 @@ static const char * const page_flag_names[] = {
[KPF_ARCH_2] = "H:arch_2",
[KPF_ANON_EXCLUSIVE] = "d:anon_exclusive",
- [KPF_READAHEAD] = "I:readahead",
[KPF_SLUB_FROZEN] = "A:slub_frozen",
[KPF_SLUB_DEBUG] = "E:slub_debug",
@@ -484,10 +482,6 @@ static uint64_t expand_overloaded_flags(uint64_t flags, uint64_t pme)
flags ^= BIT(ERROR) | BIT(SLUB_DEBUG);
}
- /* PG_reclaim is overloaded as PG_readahead in the read path */
- if ((flags & (BIT(RECLAIM) | BIT(WRITEBACK))) == BIT(RECLAIM))
- flags ^= BIT(RECLAIM) | BIT(READAHEAD);
-
if (pme & PM_SOFT_DIRTY)
flags |= BIT(SOFTDIRTY);
if (pme & PM_FILE)
--
2.45.2
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