mm: vmalloc: clean up vunmap to avoid pgtable ops twice
vunmap does page table clear operations twice in the case when DEBUG_PAGEALLOC_ENABLE_DEFAULT is enabled. So, clean up the code as that is unintended. As a perf gain, we save few us. Below ftrace data was obtained while doing 1 MB of vmalloc/vfree on ARM64 based SoC *without* this patch applied. After this patch, we can save ~3 us (on 1 extra vunmap_page_range). CPU DURATION FUNCTION CALLS | | | | | | | 6) | __vunmap() { 6) | vmap_debug_free_range() { 6) 3.281 us | vunmap_page_range(); 6) + 45.468 us | } 6) 2.760 us | vunmap_page_range(); 6) ! 505.105 us | } [cpandya@codeaurora.org: v3] Link: http://lkml.kernel.org/r/1525176960-18408-1-git-send-email-cpandya@codeaurora.org Link: http://lkml.kernel.org/r/1523876342-10545-1-git-send-email-cpandya@codeaurora.orgSigned-off-by: NChintan Pandya <cpandya@codeaurora.org> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Laura Abbott <labbott@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Yisheng Xie <xieyisheng1@huawei.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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