From: Eric Dumazet <edumazet@google.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: [PATCH] dma-debug: increase HASH_SIZE
Date: Wed, 30 Oct 2019 11:48:44 -0700 [thread overview]
Message-ID: <20191030184844.84219-1-edumazet@google.com> (raw)
With modern NIC, it is not unusual having about ~256,000 active dma
mappings. Hash size of 1024 buckets is too small.
Forcing full cache line per bucket does not seem useful,
especially now that we have a contention on free_entries_lock
for allocations and freeing of entries. Better using space
to fit more buckets.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
---
kernel/dma/debug.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 4ad74f5987ea9e95f9bb5e2d1592254e367d24fb..35e2a853bff9c482d789ab331d79aaee07753a97 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -27,7 +27,7 @@
#include <asm/sections.h>
-#define HASH_SIZE 1024ULL
+#define HASH_SIZE 16384ULL
#define HASH_FN_SHIFT 13
#define HASH_FN_MASK (HASH_SIZE - 1)
@@ -87,7 +87,7 @@ typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
struct hash_bucket {
struct list_head list;
spinlock_t lock;
-} ____cacheline_aligned_in_smp;
+};
/* Hash list to save the allocated dma addresses */
static struct hash_bucket dma_entry_hash[HASH_SIZE];
--
2.24.0.rc0.303.g954a862665-goog
next reply other threads:[~2019-10-30 18:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-30 18:48 Eric Dumazet [this message]
2019-11-07 17:44 ` [PATCH] dma-debug: increase HASH_SIZE Christoph Hellwig
2019-12-10 14:55 ` Geert Uytterhoeven
2019-12-10 15:04 ` Eric Dumazet
2019-12-10 15:07 ` Geert Uytterhoeven
2020-01-30 16:27 ` Christoph Hellwig
2020-01-30 16:43 ` Eric Dumazet
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=20191030184844.84219-1-edumazet@google.com \
--to=edumazet@google.com \
--cc=eric.dumazet@gmail.com \
--cc=hch@lst.de \
--cc=linux-kernel@vger.kernel.org \
--cc=m.szyprowski@samsung.com \
/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).