LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Muchun Song <songmuchun@bytedance.com>
To: guro@fb.com, hannes@cmpxchg.org, mhocko@kernel.org,
	akpm@linux-foundation.org, shakeelb@google.com,
	vdavydov.dev@gmail.com, willy@infradead.org
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH] mm: introduce PAGEFLAGS_MASK to replace ((1UL << NR_PAGEFLAGS) - 1)
Date: Tue, 17 Aug 2021 11:30:32 +0800	[thread overview]
Message-ID: <20210817033032.76089-1-songmuchun@bytedance.com> (raw)

Instead of hard-coding ((1UL << NR_PAGEFLAGS) - 1) everywhere, introducing
PAGEFLAGS_MASK to make the code clear to get the page flags.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 include/linux/page-flags.h      | 4 +++-
 include/trace/events/page_ref.h | 4 ++--
 lib/test_printf.c               | 2 +-
 lib/vsprintf.c                  | 2 +-
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 54c4af35c628..1f951ac24a5e 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -180,6 +180,8 @@ enum pageflags {
 	PG_reported = PG_uptodate,
 };
 
+#define PAGEFLAGS_MASK		(~((1UL << NR_PAGEFLAGS) - 1))
+
 #ifndef __GENERATING_BOUNDS_H
 
 static inline unsigned long _compound_head(const struct page *page)
@@ -975,7 +977,7 @@ static inline void ClearPageSlabPfmemalloc(struct page *page)
  * alloc-free cycle to prevent from reusing the page.
  */
 #define PAGE_FLAGS_CHECK_AT_PREP	\
-	(((1UL << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
+	(~(PAGEFLAGS_MASK | __PG_HWPOISON))
 
 #define PAGE_FLAGS_PRIVATE				\
 	(1UL << PG_private | 1UL << PG_private_2)
diff --git a/include/trace/events/page_ref.h b/include/trace/events/page_ref.h
index 5d2ea93956ce..643b1b4e9f27 100644
--- a/include/trace/events/page_ref.h
+++ b/include/trace/events/page_ref.h
@@ -38,7 +38,7 @@ DECLARE_EVENT_CLASS(page_ref_mod_template,
 
 	TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%d val=%d",
 		__entry->pfn,
-		show_page_flags(__entry->flags & ((1UL << NR_PAGEFLAGS) - 1)),
+		show_page_flags(__entry->flags & ~PAGEFLAGS_MASK),
 		__entry->count,
 		__entry->mapcount, __entry->mapping, __entry->mt,
 		__entry->val)
@@ -88,7 +88,7 @@ DECLARE_EVENT_CLASS(page_ref_mod_and_test_template,
 
 	TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%d val=%d ret=%d",
 		__entry->pfn,
-		show_page_flags(__entry->flags & ((1UL << NR_PAGEFLAGS) - 1)),
+		show_page_flags(__entry->flags & ~PAGEFLAGS_MASK),
 		__entry->count,
 		__entry->mapcount, __entry->mapping, __entry->mt,
 		__entry->val, __entry->ret)
diff --git a/lib/test_printf.c b/lib/test_printf.c
index 8ac71aee46af..eadcc6458b10 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -614,7 +614,7 @@ page_flags_test(int section, int node, int zone, int last_cpupid,
 	bool append = false;
 	int i;
 
-	flags &= BIT(NR_PAGEFLAGS) - 1;
+	flags &= ~PAGEFLAGS_MASK;
 	if (flags) {
 		page_flags |= flags;
 		snprintf(cmp_buf + size, BUF_SIZE - size, "%s", name);
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index dd006adfe853..ff7c180a2971 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2019,7 +2019,7 @@ static const struct page_flags_fields pff[] = {
 static
 char *format_page_flags(char *buf, char *end, unsigned long flags)
 {
-	unsigned long main_flags = flags & (BIT(NR_PAGEFLAGS) - 1);
+	unsigned long main_flags = flags & ~PAGEFLAGS_MASK;
 	bool append = false;
 	int i;
 
-- 
2.11.0


             reply	other threads:[~2021-08-17  3:31 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17  3:30 Muchun Song [this message]
2021-08-18  2:16 ` Roman Gushchin
2021-08-18  4:35   ` Muchun Song
2021-08-18  4:44     ` Roman Gushchin
2021-08-18  5:32       ` Muchun Song
2021-08-18  7:39       ` Andrew Morton
2021-08-19  6:33         ` Muchun Song
2021-08-19 11:18           ` Johannes Weiner
2021-08-19 15:05             ` Muchun Song

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=20210817033032.76089-1-songmuchun@bytedance.com \
    --to=songmuchun@bytedance.com \
    --cc=akpm@linux-foundation.org \
    --cc=guro@fb.com \
    --cc=hannes@cmpxchg.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=shakeelb@google.com \
    --cc=vdavydov.dev@gmail.com \
    --cc=willy@infradead.org \
    --subject='Re: [PATCH] mm: introduce PAGEFLAGS_MASK to replace ((1UL << NR_PAGEFLAGS) - 1)' \
    /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

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).