From: Andrew Morton <akpm@linux-foundation.org>
To: "zhaoyang.huang" <zhaoyang.huang@unisoc.com>
Cc: Zhaoyang Huang <huangzhaoyang@gmail.com>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>, <ke.wang@unisoc.com>
Subject: Re: [PATCHv2] mm: No need to check pcp page when free it to buddy
Date: Thu, 15 Sep 2022 15:05:57 -0700 [thread overview]
Message-ID: <20220915150557.90323a44dd1f9d33e5100350@linux-foundation.org> (raw)
In-Reply-To: <1663209654-14727-1-git-send-email-zhaoyang.huang@unisoc.com>
On Thu, 15 Sep 2022 10:40:54 +0800 "zhaoyang.huang" <zhaoyang.huang@unisoc.com> wrote:
> From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
>
> The pages on pcp list have been checked the validity via bellowing call chain.
> It is no need to check it again when free them back to buddy by free_pcppages_bulk.
>
> free_unref_page\free_unref_page_list
> {
> ...
> //page's validity is checked here
> if (!free_unref_page_prepare(page, pfn, order))
> return;
> ...
> //page added to pcp->lists and status is ready for moving to buddy
> list_add(&page->lru, &pcp->lists[pindex]);
>
The comment over free_pcp_prepare():
/*
* With DEBUG_VM enabled, order-0 pages are checked immediately when being freed
* to pcp lists. With debug_pagealloc also enabled, they are also rechecked when
* moved from pcp lists to free lists.
*/
Which seems sensible - a page's state may have been messed up while
it's in the pcp lists.
prev parent reply other threads:[~2022-09-15 22:06 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-15 2:40 [PATCHv2] mm: No need to check pcp page when free it to buddy zhaoyang.huang
2022-09-15 22:05 ` Andrew Morton [this message]
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