From: Rik van Riel <riel@redhat.com> To: Leon Romanovsky <leon@leon.nu>, Ebru Akagunduz <ebru.akagunduz@gmail.com> Cc: Linux-MM <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com, aarcange <aarcange@redhat.com>, iamjoonsoo.kim@lge.com, Xiexiuqi <xiexiuqi@huawei.com>, gorcunov@openvz.org, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>, rientjes@google.com, Vlastimil Babka <vbabka@suse.cz>, aneesh.kumar@linux.vnet.ibm.com, hughd@google.com, Johannes Weiner <hannes@cmpxchg.org>, mhocko@suse.cz, boaz@plexistor.com, raindel@mellanox.com Subject: Re: [RFC 2/3] mm: make optimistic check for swapin readahead Date: Mon, 15 Jun 2015 01:43:03 -0400 [thread overview] Message-ID: <557E65E7.9010000@redhat.com> (raw) In-Reply-To: <CALq1K=JzAWt2NUB8SOitBcXeegFTA5OOUm7NsxE3RGTzkuWfuA@mail.gmail.com> On 06/15/2015 01:40 AM, Leon Romanovsky wrote: > On Sun, Jun 14, 2015 at 6:04 PM, Ebru Akagunduz > <ebru.akagunduz@gmail.com> wrote: >> This patch makes optimistic check for swapin readahead >> to increase thp collapse rate. Before getting swapped >> out pages to memory, checks them and allows up to a >> certain number. It also prints out using tracepoints >> amount of unmapped ptes. >> >> Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com> >> @@ -2639,11 +2640,11 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, >> { >> pmd_t *pmd; >> pte_t *pte, *_pte; >> - int ret = 0, none_or_zero = 0; >> + int ret = 0, none_or_zero = 0, unmapped = 0; >> struct page *page; >> unsigned long _address; >> spinlock_t *ptl; >> - int node = NUMA_NO_NODE; >> + int node = NUMA_NO_NODE, max_ptes_swap = HPAGE_PMD_NR/8; > Sorry for asking, my knoweldge of THP is very limited, but why did you > choose this default value? > From the discussion followed by your patch > (https://lkml.org/lkml/2015/2/27/432), I got an impression that it is > not necessary right value. I believe that Ebru's main focus for this initial version of the patch series was to get the _mechanism_ (patch 3) right, while having a fairly simple policy to drive it. Any suggestions on when it is a good idea to bring in pages from swap, and whether to treat resident-in-swap-cache pages differently from need-to-be-paged-in pages, and what other factors should be examined, are very welcome... -- All rights reversed
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com> To: Leon Romanovsky <leon@leon.nu>, Ebru Akagunduz <ebru.akagunduz@gmail.com> Cc: Linux-MM <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com, aarcange <aarcange@redhat.com>, iamjoonsoo.kim@lge.com, Xiexiuqi <xiexiuqi@huawei.com>, gorcunov@openvz.org, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>, rientjes@google.com, Vlastimil Babka <vbabka@suse.cz>, aneesh.kumar@linux.vnet.ibm.com, hughd@google.com, Johannes Weiner <hannes@cmpxchg.org>, mhocko@suse.cz, boaz@plexistor.com, raindel@mellanox.com Subject: Re: [RFC 2/3] mm: make optimistic check for swapin readahead Date: Mon, 15 Jun 2015 01:43:03 -0400 [thread overview] Message-ID: <557E65E7.9010000@redhat.com> (raw) In-Reply-To: <CALq1K=JzAWt2NUB8SOitBcXeegFTA5OOUm7NsxE3RGTzkuWfuA@mail.gmail.com> On 06/15/2015 01:40 AM, Leon Romanovsky wrote: > On Sun, Jun 14, 2015 at 6:04 PM, Ebru Akagunduz > <ebru.akagunduz@gmail.com> wrote: >> This patch makes optimistic check for swapin readahead >> to increase thp collapse rate. Before getting swapped >> out pages to memory, checks them and allows up to a >> certain number. It also prints out using tracepoints >> amount of unmapped ptes. >> >> Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com> >> @@ -2639,11 +2640,11 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, >> { >> pmd_t *pmd; >> pte_t *pte, *_pte; >> - int ret = 0, none_or_zero = 0; >> + int ret = 0, none_or_zero = 0, unmapped = 0; >> struct page *page; >> unsigned long _address; >> spinlock_t *ptl; >> - int node = NUMA_NO_NODE; >> + int node = NUMA_NO_NODE, max_ptes_swap = HPAGE_PMD_NR/8; > Sorry for asking, my knoweldge of THP is very limited, but why did you > choose this default value? > From the discussion followed by your patch > (https://lkml.org/lkml/2015/2/27/432), I got an impression that it is > not necessary right value. I believe that Ebru's main focus for this initial version of the patch series was to get the _mechanism_ (patch 3) right, while having a fairly simple policy to drive it. Any suggestions on when it is a good idea to bring in pages from swap, and whether to treat resident-in-swap-cache pages differently from need-to-be-paged-in pages, and what other factors should be examined, are very welcome... -- All rights reversed -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2015-06-15 5:43 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-06-14 15:04 [RFC 0/3] mm: make swapin readahead to gain more thp performance Ebru Akagunduz 2015-06-14 15:04 ` Ebru Akagunduz 2015-06-14 15:04 ` [RFC 1/3] mm: add tracepoint for scanning pages Ebru Akagunduz 2015-06-14 15:04 ` Ebru Akagunduz 2015-06-15 1:04 ` Rik van Riel 2015-06-15 1:04 ` Rik van Riel 2015-06-14 15:04 ` [RFC 2/3] mm: make optimistic check for swapin readahead Ebru Akagunduz 2015-06-14 15:04 ` Ebru Akagunduz 2015-06-15 5:40 ` Leon Romanovsky 2015-06-15 5:40 ` Leon Romanovsky 2015-06-15 5:43 ` Rik van Riel [this message] 2015-06-15 5:43 ` Rik van Riel 2015-06-15 6:08 ` Leon Romanovsky 2015-06-15 6:08 ` Leon Romanovsky 2015-06-15 6:35 ` Rik van Riel 2015-06-15 6:35 ` Rik van Riel 2015-06-15 14:05 ` Rik van Riel 2015-06-15 14:05 ` Rik van Riel 2015-06-15 16:07 ` Leon Romanovsky 2015-06-15 16:07 ` Leon Romanovsky 2015-06-14 15:04 ` [RFC 3/3] mm: make swapin readahead to improve thp collapse rate Ebru Akagunduz 2015-06-14 15:04 ` Ebru Akagunduz 2015-06-15 13:59 ` Rik van Riel 2015-06-15 13:59 ` Rik van Riel 2015-06-16 21:15 ` Andrew Morton 2015-06-16 21:15 ` Andrew Morton 2015-06-17 3:20 ` Rik van Riel 2015-06-17 3:20 ` Rik van Riel 2015-06-17 17:38 ` Ebru Akagunduz 2015-06-17 17:38 ` Ebru Akagunduz
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