linux-kernel - Re: [PATCH uprobe, thp 2/4] uprobe: use original page when all uprobes are removed

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Message-ID: <20190530111739.r6b2hpzjadep4xr5@box>
Date:   Thu, 30 May 2019 14:17:39 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Song Liu <songliubraving@...com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org, namit@...are.com,
        peterz@...radead.org, oleg@...hat.com, rostedt@...dmis.org,
        mhiramat@...nel.org, matthew.wilcox@...cle.com,
        kirill.shutemov@...ux.intel.com, kernel-team@...com,
        william.kucharski@...cle.com, chad.mynhier@...cle.com,
        mike.kravetz@...cle.com
Subject: Re: [PATCH uprobe, thp 2/4] uprobe: use original page when all
 uprobes are removed

On Wed, May 29, 2019 at 02:20:47PM -0700, Song Liu wrote:
> @@ -501,6 +512,20 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
>  	copy_highpage(new_page, old_page);
>  	copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
>  
> +	index = vaddr_to_offset(vma, vaddr & PAGE_MASK) >> PAGE_SHIFT;
> +	orig_page = find_get_page(vma->vm_file->f_inode->i_mapping, index);
> +	if (orig_page) {
> +		if (memcmp(page_address(orig_page),
> +			   page_address(new_page), PAGE_SIZE) == 0) {

Does it work for highmem?


-- 
 Kirill A. Shutemov