linux-kernel - Re: [PATCH v11 2/4] uprobe: use original page when all uprobes are removed

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Date:   Wed, 31 Jul 2019 12:10:12 +0530
From:   Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:     Song Liu <songliubraving@...com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        akpm@...ux-foundation.org, matthew.wilcox@...cle.com,
        kirill.shutemov@...ux.intel.com, oleg@...hat.com,
        kernel-team@...com, william.kucharski@...cle.com
Subject: Re: [PATCH v11 2/4] uprobe: use original page when all uprobes are
 removed

* Song Liu <songliubraving@...com> [2019-07-30 12:30:59]:

> Currently, uprobe swaps the target page with a anonymous page in both
> install_breakpoint() and remove_breakpoint(). When all uprobes on a page
> are removed, the given mm is still using an anonymous page (not the
> original page).
> 
> This patch allows uprobe to use original page when possible (all uprobes
> on the page are already removed, and the original page is in page cache
> and uptodate).
> 
> As suggested by Oleg, we unmap the old_page and let the original page
> fault in.
> 
> Suggested-by: Oleg Nesterov <oleg@...hat.com>
> Signed-off-by: Song Liu <songliubraving@...com>

Looks good to me.

Reviewed-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>

-- 
Thanks and Regards
Srikar Dronamraju