From: Zhihong Wang <zhihong.wang@intel.com>
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH RFC v2 2/2] lib/librte_eal: Remove unnecessary hugepage zero-filling
Date: Thu, 19 Nov 2015 20:53:48 -0500 [thread overview]
Message-ID: <1447984428-137897-3-git-send-email-zhihong.wang@intel.com> (raw)
In-Reply-To: <1447984428-137897-1-git-send-email-zhihong.wang@intel.com>
The kernel fills new allocated (huge) pages with zeros.
DPDK just has to touch the pages to trigger the allocation.
Signed-off-by: Zhihong Wang <zhihong.wang@intel.com>
---
lib/librte_eal/linuxapp/eal/eal_memory.c | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)
diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index 0de75cd..21a5146 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -399,8 +399,10 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl,
return -1;
}
+ /* map the segment, and populate page tables,
+ * the kernel fills this segment with zeros */
virtaddr = mmap(vma_addr, hugepage_sz, PROT_READ | PROT_WRITE,
- MAP_SHARED, fd, 0);
+ MAP_SHARED | MAP_POPULATE, fd, 0);
if (virtaddr == MAP_FAILED) {
RTE_LOG(ERR, EAL, "%s(): mmap failed: %s\n", __func__,
strerror(errno));
@@ -410,7 +412,6 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl,
if (orig) {
hugepg_tbl[i].orig_va = virtaddr;
- memset(virtaddr, 0, hugepage_sz);
}
else {
hugepg_tbl[i].final_va = virtaddr;
@@ -529,22 +530,16 @@ remap_all_hugepages(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
old_addr = vma_addr;
- /* map new, bigger segment */
+ /* map new, bigger segment, and populate page tables,
+ * the kernel fills this segment with zeros */
vma_addr = mmap(vma_addr, total_size,
- PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+ PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, 0);
if (vma_addr == MAP_FAILED || vma_addr != old_addr) {
RTE_LOG(ERR, EAL, "%s(): mmap failed: %s\n", __func__, strerror(errno));
close(fd);
return -1;
}
-
- /* touch the page. this is needed because kernel postpones mapping
- * creation until the first page fault. with this, we pin down
- * the page and it is marked as used and gets into process' pagemap.
- */
- for (offset = 0; offset < total_size; offset += hugepage_sz)
- *((volatile uint8_t*) RTE_PTR_ADD(vma_addr, offset));
}
/* set shared flock on the file. */
@@ -592,9 +587,6 @@ remap_all_hugepages(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
}
}
- /* zero out the whole segment */
- memset(hugepg_tbl[page_idx].final_va, 0, total_size);
-
page_idx++;
}
--
2.5.0
next prev parent reply other threads:[~2015-11-20 8:56 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-20 1:53 [dpdk-dev] [PATCH RFC v2 0/2] Reduce DPDK initialization time Zhihong Wang
2015-11-20 1:53 ` [dpdk-dev] [PATCH RFC v2 1/2] lib/librte_eal: Reduce timer " Zhihong Wang
2015-11-20 16:31 ` Stephen Hemminger
2015-11-23 1:29 ` Wang, Zhihong
2015-11-20 1:53 ` Zhihong Wang [this message]
2015-11-20 16:32 ` [dpdk-dev] [PATCH RFC v2 2/2] lib/librte_eal: Remove unnecessary hugepage zero-filling Stephen Hemminger
2015-11-23 1:31 ` Wang, Zhihong
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=1447984428-137897-3-git-send-email-zhihong.wang@intel.com \
--to=zhihong.wang@intel.com \
--cc=dev@dpdk.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).