From: Alex Shi <alex.shi@linux.alibaba.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Wei Yang <richard.weiyang@gmail.com>,
Hugh Dickins <hughd@google.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Andrea Arcangeli <aarcange@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH 4/4] mm/thp: narrow lru locking
Date: Sat, 1 Aug 2020 12:09:17 +0800 [thread overview]
Message-ID: <1596254957-22560-4-git-send-email-alex.shi@linux.alibaba.com> (raw)
In-Reply-To: <1596254957-22560-1-git-send-email-alex.shi@linux.alibaba.com>
lru_lock and page cache xa_lock have no reason with current sequence,
put them together isn't necessary. let's narrow the lru locking, but
left the local_irq_disable to block interrupt re-entry and statistic update.
Hugh Dickins point: split_huge_page_to_list() was already silly,to be
using the _irqsave variant: it's just been taking sleeping locks, so
would already be broken if entered with interrupts enabled.
so we can save passing flags argument down to __split_huge_page().
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
mm/huge_memory.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index dfe7378ab4be..070480e66bf4 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2398,7 +2398,7 @@ static void __split_huge_page_tail(struct page *head, int tail,
}
static void __split_huge_page(struct page *page, struct list_head *list,
- pgoff_t end, unsigned long flags)
+ pgoff_t end)
{
struct page *head = compound_head(page);
pg_data_t *pgdat = page_pgdat(head);
@@ -2407,8 +2407,6 @@ static void __split_huge_page(struct page *page, struct list_head *list,
unsigned long offset = 0;
int i;
- lruvec = mem_cgroup_page_lruvec(head, pgdat);
-
/* complete memcg works before add pages to LRU */
mem_cgroup_split_huge_fixup(head);
@@ -2420,6 +2418,11 @@ static void __split_huge_page(struct page *page, struct list_head *list,
xa_lock(&swap_cache->i_pages);
}
+ /* prevent PageLRU to go away from under us, and freeze lru stats */
+ spin_lock(&pgdat->lru_lock);
+
+ lruvec = mem_cgroup_page_lruvec(head, pgdat);
+
for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
__split_huge_page_tail(head, i, lruvec, list);
/* Some pages can be beyond i_size: drop them from page cache */
@@ -2439,6 +2442,8 @@ static void __split_huge_page(struct page *page, struct list_head *list,
}
ClearPageCompound(head);
+ spin_unlock(&pgdat->lru_lock);
+ /* Caller disabled irqs, so they are still disabled here */
split_page_owner(head, HPAGE_PMD_ORDER);
@@ -2456,8 +2461,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
page_ref_add(head, 2);
xa_unlock(&head->mapping->i_pages);
}
-
- spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+ local_irq_enable();
remap_page(head);
@@ -2596,12 +2600,10 @@ bool can_split_huge_page(struct page *page, int *pextra_pins)
int split_huge_page_to_list(struct page *page, struct list_head *list)
{
struct page *head = compound_head(page);
- struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
struct deferred_split *ds_queue = get_deferred_split_queue(head);
struct anon_vma *anon_vma = NULL;
struct address_space *mapping = NULL;
int count, mapcount, extra_pins, ret;
- unsigned long flags;
pgoff_t end;
VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
@@ -2662,9 +2664,8 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
unmap_page(head);
VM_BUG_ON_PAGE(compound_mapcount(head), head);
- /* prevent PageLRU to go away from under us, and freeze lru stats */
- spin_lock_irqsave(&pgdata->lru_lock, flags);
-
+ /* block interrupt reentry in xa_lock and spinlock */
+ local_irq_disable();
if (mapping) {
XA_STATE(xas, &mapping->i_pages, page_index(head));
@@ -2694,7 +2695,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
__dec_node_page_state(head, NR_FILE_THPS);
}
- __split_huge_page(page, list, end, flags);
+ __split_huge_page(page, list, end);
if (PageSwapCache(head)) {
swp_entry_t entry = { .val = page_private(head) };
@@ -2713,7 +2714,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
spin_unlock(&ds_queue->split_queue_lock);
fail: if (mapping)
xa_unlock(&mapping->i_pages);
- spin_unlock_irqrestore(&pgdata->lru_lock, flags);
+ local_irq_enable();
remap_page(head);
ret = -EBUSY;
}
--
1.8.3.1
next prev parent reply other threads:[~2020-08-01 4:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-01 4:09 [PATCH 1/4] mm/thp: move lru_add_page_tail func to huge_memory.c Alex Shi
2020-08-01 4:09 ` [PATCH 2/4] mm/thp: clean up lru_add_page_tail Alex Shi
2020-08-01 4:09 ` [PATCH 3/4] mm/thp: remove code path which never got into Alex Shi
2020-08-01 4:09 ` Alex Shi [this message]
2020-08-02 11:09 ` [PATCH 4/4] mm/thp: narrow lru locking Matthew Wilcox
2020-08-02 13:24 ` Alex Shi
2020-08-01 4:11 ` [PATCH 1/4] mm/thp: move lru_add_page_tail func to huge_memory.c Alex Shi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1596254957-22560-4-git-send-email-alex.shi@linux.alibaba.com \
--to=alex.shi@linux.alibaba.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=richard.weiyang@gmail.com \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).